postgresql/src/backend/commands/dbcommands.c

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/*-------------------------------------------------------------------------
*
* dbcommands.c
Clean up various to-do items associated with system indexes: pg_database now has unique indexes on oid and on datname. pg_shadow now has unique indexes on usename and on usesysid. pg_am now has unique index on oid. pg_opclass now has unique index on oid. pg_amproc now has unique index on amid+amopclaid+amprocnum. Remove pg_rewrite's unnecessary index on oid, delete unused RULEOID syscache. Remove index on pg_listener and associated syscache for performance reasons (caching rows that are certain to change before you need 'em again is rather pointless). Change pg_attrdef's nonunique index on adrelid into a unique index on adrelid+adnum. Fix various incorrect settings of pg_class.relisshared, make that the primary reference point for whether a relation is shared or not. IsSharedSystemRelationName() is now only consulted to initialize relisshared during initial creation of tables and indexes. In theory we might now support shared user relations, though it's not clear how one would get entries for them into pg_class &etc of multiple databases. Fix recently reported bug that pg_attribute rows created for an index all have the same OID. (Proof that non-unique OID doesn't matter unless it's actually used to do lookups ;-)) There's no need to treat pg_trigger, pg_attrdef, pg_relcheck as bootstrap relations. Convert them into plain system catalogs without hardwired entries in pg_class and friends. Unify global.bki and template1.bki into a single init script postgres.bki, since the alleged distinction between them was misleading and pointless. Not to mention that it didn't work for setting up indexes on shared system relations. Rationalize locking of pg_shadow, pg_group, pg_attrdef (no need to use AccessExclusiveLock where ExclusiveLock or even RowExclusiveLock will do). Also, hold locks until transaction commit where necessary.
2001-06-12 07:55:50 +02:00
* Database management commands (create/drop database).
*
* Note: database creation/destruction commands use exclusive locks on
* the database objects (as expressed by LockSharedObject()) to avoid
* stepping on each others' toes. Formerly we used table-level locks
* on pg_database, but that's too coarse-grained.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
2010-09-20 22:08:53 +02:00
* src/backend/commands/dbcommands.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
2003-06-27 16:45:32 +02:00
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/multixact.h"
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
#include "access/tableam.h"
#include "access/xact.h"
#include "access/xloginsert.h"
#include "access/xlogutils.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_database.h"
#include "catalog/pg_db_role_setting.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "commands/comment.h"
#include "commands/dbcommands.h"
#include "commands/dbcommands_xlog.h"
#include "commands/defrem.h"
#include "commands/seclabel.h"
#include "commands/tablespace.h"
#include "mb/pg_wchar.h"
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#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/bgwriter.h"
#include "replication/slot.h"
#include "storage/copydir.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lmgr.h"
#include "storage/md.h"
#include "storage/procarray.h"
#include "storage/smgr.h"
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#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/pg_locale.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
typedef struct
{
Oid src_dboid; /* source (template) DB */
Oid dest_dboid; /* DB we are trying to create */
} createdb_failure_params;
typedef struct
{
Oid dest_dboid; /* DB we are trying to move */
Oid dest_tsoid; /* tablespace we are trying to move to */
} movedb_failure_params;
/* non-export function prototypes */
static void createdb_failure_callback(int code, Datum arg);
static void movedb(const char *dbname, const char *tblspcname);
static void movedb_failure_callback(int code, Datum arg);
static bool get_db_info(const char *name, LOCKMODE lockmode,
Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP, TransactionId *dbFrozenXidP,
MultiXactId *dbMinMultiP,
Oid *dbTablespace, char **dbCollate, char **dbCtype);
static bool have_createdb_privilege(void);
static void remove_dbtablespaces(Oid db_id);
static bool check_db_file_conflict(Oid db_id);
static int errdetail_busy_db(int notherbackends, int npreparedxacts);
/*
* CREATE DATABASE
*/
Oid
createdb(ParseState *pstate, const CreatedbStmt *stmt)
{
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
TableScanDesc scan;
Relation rel;
Oid src_dboid;
Oid src_owner;
int src_encoding = -1;
char *src_collate = NULL;
char *src_ctype = NULL;
bool src_istemplate;
bool src_allowconn;
Oid src_lastsysoid = InvalidOid;
TransactionId src_frozenxid = InvalidTransactionId;
MultiXactId src_minmxid = InvalidMultiXactId;
Oid src_deftablespace;
volatile Oid dst_deftablespace;
Relation pg_database_rel;
HeapTuple tuple;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
Oid dboid;
Oid datdba;
ListCell *option;
2004-08-29 07:07:03 +02:00
DefElem *dtablespacename = NULL;
DefElem *downer = NULL;
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DefElem *dtemplate = NULL;
DefElem *dencoding = NULL;
DefElem *dlocale = NULL;
DefElem *dcollate = NULL;
DefElem *dctype = NULL;
DefElem *distemplate = NULL;
DefElem *dallowconnections = NULL;
DefElem *dconnlimit = NULL;
char *dbname = stmt->dbname;
char *dbowner = NULL;
const char *dbtemplate = NULL;
char *dbcollate = NULL;
char *dbctype = NULL;
char *canonname;
int encoding = -1;
bool dbistemplate = false;
bool dballowconnections = true;
int dbconnlimit = -1;
int notherbackends;
int npreparedxacts;
createdb_failure_params fparms;
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
if (strcmp(defel->defname, "tablespace") == 0)
{
if (dtablespacename)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtablespacename = defel;
}
else if (strcmp(defel->defname, "owner") == 0)
{
if (downer)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
downer = defel;
}
else if (strcmp(defel->defname, "template") == 0)
{
if (dtemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtemplate = defel;
}
else if (strcmp(defel->defname, "encoding") == 0)
{
if (dencoding)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dencoding = defel;
}
else if (strcmp(defel->defname, "locale") == 0)
{
if (dlocale)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dlocale = defel;
}
else if (strcmp(defel->defname, "lc_collate") == 0)
{
if (dcollate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dcollate = defel;
}
else if (strcmp(defel->defname, "lc_ctype") == 0)
{
if (dctype)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dctype = defel;
}
else if (strcmp(defel->defname, "is_template") == 0)
{
if (distemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
distemplate = defel;
}
else if (strcmp(defel->defname, "allow_connections") == 0)
{
if (dallowconnections)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dallowconnections = defel;
}
else if (strcmp(defel->defname, "connection_limit") == 0)
{
if (dconnlimit)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dconnlimit = defel;
}
else if (strcmp(defel->defname, "location") == 0)
{
ereport(WARNING,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("LOCATION is not supported anymore"),
errhint("Consider using tablespaces instead."),
parser_errposition(pstate, defel->location)));
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("option \"%s\" not recognized", defel->defname),
parser_errposition(pstate, defel->location)));
}
if (dlocale && (dcollate || dctype))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
errdetail("LOCALE cannot be specified together with LC_COLLATE or LC_CTYPE.")));
if (downer && downer->arg)
dbowner = defGetString(downer);
if (dtemplate && dtemplate->arg)
dbtemplate = defGetString(dtemplate);
if (dencoding && dencoding->arg)
{
const char *encoding_name;
if (IsA(dencoding->arg, Integer))
{
encoding = defGetInt32(dencoding);
encoding_name = pg_encoding_to_char(encoding);
if (strcmp(encoding_name, "") == 0 ||
pg_valid_server_encoding(encoding_name) < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%d is not a valid encoding code",
encoding),
parser_errposition(pstate, dencoding->location)));
}
else
{
encoding_name = defGetString(dencoding);
Fix the inadvertent libpq ABI breakage discovered by Martin Pitt: the renumbering of encoding IDs done between 8.2 and 8.3 turns out to break 8.2 initdb and psql if they are run with an 8.3beta1 libpq.so. For the moment we can rearrange the order of enum pg_enc to keep the same number for everything except PG_JOHAB, which isn't a problem since there are no direct references to it in the 8.2 programs anyway. (This does force initdb unfortunately.) Going forward, we want to fix things so that encoding IDs can be changed without an ABI break, and this commit includes the changes needed to allow libpq's encoding IDs to be treated as fully independent of the backend's. The main issue is that libpq clients should not include pg_wchar.h or otherwise assume they know the specific values of libpq's encoding IDs, since they might encounter version skew between pg_wchar.h and the libpq.so they are using. To fix, have libpq officially export functions needed for encoding name<=>ID conversion and validity checking; it was doing this anyway unofficially. It's still the case that we can't renumber backend encoding IDs until the next bump in libpq's major version number, since doing so will break the 8.2-era client programs. However the code is now prepared to avoid this type of problem in future. Note that initdb is no longer a libpq client: we just pull in the two source files we need directly. The patch also fixes a few places that were being sloppy about checking for an unrecognized encoding name.
2007-10-13 22:18:42 +02:00
encoding = pg_valid_server_encoding(encoding_name);
if (encoding < 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("%s is not a valid encoding name",
encoding_name),
parser_errposition(pstate, dencoding->location)));
}
}
if (dlocale && dlocale->arg)
{
dbcollate = defGetString(dlocale);
dbctype = defGetString(dlocale);
}
if (dcollate && dcollate->arg)
dbcollate = defGetString(dcollate);
if (dctype && dctype->arg)
dbctype = defGetString(dctype);
if (distemplate && distemplate->arg)
dbistemplate = defGetBoolean(distemplate);
if (dallowconnections && dallowconnections->arg)
dballowconnections = defGetBoolean(dallowconnections);
if (dconnlimit && dconnlimit->arg)
{
dbconnlimit = defGetInt32(dconnlimit);
if (dbconnlimit < -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid connection limit: %d", dbconnlimit)));
}
/* obtain OID of proposed owner */
if (dbowner)
datdba = get_role_oid(dbowner, false);
else
datdba = GetUserId();
/*
2005-10-15 04:49:52 +02:00
* To create a database, must have createdb privilege and must be able to
* become the target role (this does not imply that the target role itself
* must have createdb privilege). The latter provision guards against
* "giveaway" attacks. Note that a superuser will always have both of
2005-10-15 04:49:52 +02:00
* these privileges a fortiori.
*/
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create database")));
check_is_member_of_role(GetUserId(), datdba);
/*
* Lookup database (template) to be cloned, and obtain share lock on it.
* ShareLock allows two CREATE DATABASEs to work from the same template
* concurrently, while ensuring no one is busy dropping it in parallel
* (which would be Very Bad since we'd likely get an incomplete copy
* without knowing it). This also prevents any new connections from being
* made to the source until we finish copying it, so we can be sure it
* won't change underneath us.
*/
if (!dbtemplate)
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:18:54 +02:00
dbtemplate = "template1"; /* Default template database name */
if (!get_db_info(dbtemplate, ShareLock,
&src_dboid, &src_owner, &src_encoding,
&src_istemplate, &src_allowconn, &src_lastsysoid,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
&src_frozenxid, &src_minmxid, &src_deftablespace,
&src_collate, &src_ctype))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("template database \"%s\" does not exist",
dbtemplate)));
2001-03-22 05:01:46 +01:00
/*
2001-03-22 05:01:46 +01:00
* Permission check: to copy a DB that's not marked datistemplate, you
* must be superuser or the owner thereof.
*/
if (!src_istemplate)
{
if (!pg_database_ownercheck(src_dboid, GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to copy database \"%s\"",
dbtemplate)));
}
2001-03-22 05:01:46 +01:00
/* If encoding or locales are defaulted, use source's setting */
if (encoding < 0)
encoding = src_encoding;
if (dbcollate == NULL)
dbcollate = src_collate;
if (dbctype == NULL)
dbctype = src_ctype;
Commit Karel's patch. ------------------------------------------------------------------- Subject: Re: [PATCHES] encoding names From: Karel Zak <zakkr@zf.jcu.cz> To: Peter Eisentraut <peter_e@gmx.net> Cc: pgsql-patches <pgsql-patches@postgresql.org> Date: Fri, 31 Aug 2001 17:24:38 +0200 On Thu, Aug 30, 2001 at 01:30:40AM +0200, Peter Eisentraut wrote: > > - convert encoding 'name' to 'id' > > I thought we decided not to add functions returning "new" names until we > know exactly what the new names should be, and pending schema Ok, the patch not to add functions. > better > > ...(): encoding name too long Fixed. I found new bug in command/variable.c in parse_client_encoding(), nobody probably never see this error: if (pg_set_client_encoding(encoding)) { elog(ERROR, "Conversion between %s and %s is not supported", value, GetDatabaseEncodingName()); } because pg_set_client_encoding() returns -1 for error and 0 as true. It's fixed too. IMHO it can be apply. Karel PS: * following files are renamed: src/utils/mb/Unicode/KOI8_to_utf8.map --> src/utils/mb/Unicode/koi8r_to_utf8.map src/utils/mb/Unicode/WIN_to_utf8.map --> src/utils/mb/Unicode/win1251_to_utf8.map src/utils/mb/Unicode/utf8_to_KOI8.map --> src/utils/mb/Unicode/utf8_to_koi8r.map src/utils/mb/Unicode/utf8_to_WIN.map --> src/utils/mb/Unicode/utf8_to_win1251.map * new file: src/utils/mb/encname.c * removed file: src/utils/mb/common.c -- Karel Zak <zakkr@zf.jcu.cz> http://home.zf.jcu.cz/~zakkr/ C, PostgreSQL, PHP, WWW, http://docs.linux.cz, http://mape.jcu.cz
2001-09-06 06:57:30 +02:00
/* Some encodings are client only */
if (!PG_VALID_BE_ENCODING(encoding))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid server encoding %d", encoding)));
/* Check that the chosen locales are valid, and get canonical spellings */
if (!check_locale(LC_COLLATE, dbcollate, &canonname))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid locale name: \"%s\"", dbcollate)));
dbcollate = canonname;
if (!check_locale(LC_CTYPE, dbctype, &canonname))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("invalid locale name: \"%s\"", dbctype)));
dbctype = canonname;
check_encoding_locale_matches(encoding, dbcollate, dbctype);
/*
* Check that the new encoding and locale settings match the source
* database. We insist on this because we simply copy the source data ---
* any non-ASCII data would be wrongly encoded, and any indexes sorted
* according to the source locale would be wrong.
*
* However, we assume that template0 doesn't contain any non-ASCII data
* nor any indexes that depend on collation or ctype, so template0 can be
* used as template for creating a database with any encoding or locale.
*/
if (strcmp(dbtemplate, "template0") != 0)
{
if (encoding != src_encoding)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new encoding (%s) is incompatible with the encoding of the template database (%s)",
pg_encoding_to_char(encoding),
pg_encoding_to_char(src_encoding)),
errhint("Use the same encoding as in the template database, or use template0 as template.")));
if (strcmp(dbcollate, src_collate) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new collation (%s) is incompatible with the collation of the template database (%s)",
dbcollate, src_collate),
2009-04-15 23:36:12 +02:00
errhint("Use the same collation as in the template database, or use template0 as template.")));
if (strcmp(dbctype, src_ctype) != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("new LC_CTYPE (%s) is incompatible with the LC_CTYPE of the template database (%s)",
dbctype, src_ctype),
2009-04-15 23:36:12 +02:00
errhint("Use the same LC_CTYPE as in the template database, or use template0 as template.")));
}
/* Resolve default tablespace for new database */
if (dtablespacename && dtablespacename->arg)
{
char *tablespacename;
2004-08-29 07:07:03 +02:00
AclResult aclresult;
tablespacename = defGetString(dtablespacename);
dst_deftablespace = get_tablespace_oid(tablespacename, false);
/* check permissions */
2004-08-29 07:07:03 +02:00
aclresult = pg_tablespace_aclcheck(dst_deftablespace, GetUserId(),
ACL_CREATE);
2004-08-29 07:07:03 +02:00
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_TABLESPACE,
2004-08-29 07:07:03 +02:00
tablespacename);
/* pg_global must never be the default tablespace */
if (dst_deftablespace == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("pg_global cannot be used as default tablespace")));
/*
* If we are trying to change the default tablespace of the template,
* we require that the template not have any files in the new default
* tablespace. This is necessary because otherwise the copied
* database would contain pg_class rows that refer to its default
* tablespace both explicitly (by OID) and implicitly (as zero), which
* would cause problems. For example another CREATE DATABASE using
* the copied database as template, and trying to change its default
* tablespace again, would yield outright incorrect results (it would
* improperly move tables to the new default tablespace that should
* stay in the same tablespace).
*/
if (dst_deftablespace != src_deftablespace)
{
char *srcpath;
struct stat st;
srcpath = GetDatabasePath(src_dboid, dst_deftablespace);
if (stat(srcpath, &st) == 0 &&
S_ISDIR(st.st_mode) &&
!directory_is_empty(srcpath))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot assign new default tablespace \"%s\"",
tablespacename),
errdetail("There is a conflict because database \"%s\" already has some tables in this tablespace.",
dbtemplate)));
pfree(srcpath);
}
}
else
{
/* Use template database's default tablespace */
dst_deftablespace = src_deftablespace;
/* Note there is no additional permission check in this path */
}
Add an enforcement mechanism for global object names in regression tests. In commit 18555b132 we tentatively established a rule that regression tests should use names containing "regression" for databases, and names starting with "regress_" for all other globally-visible object names, so as to circumscribe the side-effects that "make installcheck" could have on an existing installation. This commit adds a simple enforcement mechanism for that rule: if the code is compiled with ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS defined, it will emit a warning (not an error) whenever a database, role, tablespace, subscription, or replication origin name is created that doesn't obey the rule. Running one or more buildfarm members with that symbol defined should be enough to catch new violations, at least in the regular regression tests. Most TAP tests wouldn't notice such warnings, but that's actually fine because TAP tests don't execute against an existing server anyway. Since it's already the case that running src/test/modules/ tests in installcheck mode is deprecated, we can use that as a home for tests that seem unsafe to run against an existing server, such as tests that might have side-effects on existing roles. Document that (though this commit doesn't in itself make it any less safe than before). Update regress.sgml to define these restrictions more clearly, and to clean up assorted lack-of-up-to-date-ness in its descriptions of the available regression tests. Discussion: https://postgr.es/m/16638.1468620817@sss.pgh.pa.us
2019-06-29 17:34:00 +02:00
/*
* If built with appropriate switch, whine when regression-testing
* conventions for database names are violated. But don't complain during
* initdb.
*/
#ifdef ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS
if (IsUnderPostmaster && strstr(dbname, "regression") == NULL)
elog(WARNING, "databases created by regression test cases should have names including \"regression\"");
#endif
2001-03-22 05:01:46 +01:00
/*
* Check for db name conflict. This is just to give a more friendly error
2006-10-04 02:30:14 +02:00
* message than "unique index violation". There's a race condition but
* we're willing to accept the less friendly message in that case.
*/
if (OidIsValid(get_database_oid(dbname, true)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", dbname)));
/*
* The source DB can't have any active backends, except this one
* (exception is to allow CREATE DB while connected to template1).
* Otherwise we might copy inconsistent data.
*
* This should be last among the basic error checks, because it involves
* potential waiting; we may as well throw an error first if we're gonna
* throw one.
*/
if (CountOtherDBBackends(src_dboid, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("source database \"%s\" is being accessed by other users",
dbtemplate),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
2007-11-15 22:14:46 +01:00
* Select an OID for the new database, checking that it doesn't have a
* filename conflict with anything already existing in the tablespace
* directories.
*/
pg_database_rel = table_open(DatabaseRelationId, RowExclusiveLock);
do
{
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
dboid = GetNewOidWithIndex(pg_database_rel, DatabaseOidIndexId,
Anum_pg_database_oid);
} while (check_db_file_conflict(dboid));
/*
2006-10-04 02:30:14 +02:00
* Insert a new tuple into pg_database. This establishes our ownership of
* the new database name (anyone else trying to insert the same name will
* block on the unique index, and fail after we commit).
*/
/* Form tuple */
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
new_record[Anum_pg_database_oid - 1] = ObjectIdGetDatum(dboid);
new_record[Anum_pg_database_datname - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbname));
new_record[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(datdba);
new_record[Anum_pg_database_encoding - 1] = Int32GetDatum(encoding);
new_record[Anum_pg_database_datcollate - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbcollate));
new_record[Anum_pg_database_datctype - 1] =
DirectFunctionCall1(namein, CStringGetDatum(dbctype));
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(dbistemplate);
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(dballowconnections);
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record[Anum_pg_database_datlastsysoid - 1] = ObjectIdGetDatum(src_lastsysoid);
new_record[Anum_pg_database_datfrozenxid - 1] = TransactionIdGetDatum(src_frozenxid);
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
new_record[Anum_pg_database_datminmxid - 1] = TransactionIdGetDatum(src_minmxid);
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_deftablespace);
/*
* We deliberately set datacl to default (NULL), rather than copying it
* from the template database. Copying it would be a bad idea when the
* owner is not the same as the template's owner.
*/
new_record_nulls[Anum_pg_database_datacl - 1] = true;
tuple = heap_form_tuple(RelationGetDescr(pg_database_rel),
new_record, new_record_nulls);
CatalogTupleInsert(pg_database_rel, tuple);
/*
* Now generate additional catalog entries associated with the new DB
*/
/* Register owner dependency */
recordDependencyOnOwner(DatabaseRelationId, dboid, datdba);
/* Create pg_shdepend entries for objects within database */
copyTemplateDependencies(src_dboid, dboid);
/* Post creation hook for new database */
InvokeObjectPostCreateHook(DatabaseRelationId, dboid, 0);
/*
* Force a checkpoint before starting the copy. This will force all dirty
* buffers, including those of unlogged tables, out to disk, to ensure
* source database is up-to-date on disk for the copy.
2015-05-24 03:35:49 +02:00
* FlushDatabaseBuffers() would suffice for that, but we also want to
* process any pending unlink requests. Otherwise, if a checkpoint
* happened while we're copying files, a file might be deleted just when
* we're about to copy it, causing the lstat() call in copydir() to fail
* with ENOENT.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT
| CHECKPOINT_FLUSH_ALL);
/*
2005-10-15 04:49:52 +02:00
* Once we start copying subdirectories, we need to be able to clean 'em
* up if we fail. Use an ENSURE block to make sure this happens. (This
2005-10-15 04:49:52 +02:00
* is not a 100% solution, because of the possibility of failure during
* transaction commit after we leave this routine, but it should handle
* most scenarios.)
*/
fparms.src_dboid = src_dboid;
fparms.dest_dboid = dboid;
PG_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
PointerGetDatum(&fparms));
{
/*
2005-10-15 04:49:52 +02:00
* Iterate through all tablespaces of the template database, and copy
* each one to the new database.
*/
rel = table_open(TableSpaceRelationId, AccessShareLock);
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
scan = table_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
Form_pg_tablespace spaceform = (Form_pg_tablespace) GETSTRUCT(tuple);
Oid srctablespace = spaceform->oid;
Oid dsttablespace;
char *srcpath;
char *dstpath;
struct stat st;
/* No need to copy global tablespace */
if (srctablespace == GLOBALTABLESPACE_OID)
continue;
srcpath = GetDatabasePath(src_dboid, srctablespace);
if (stat(srcpath, &st) < 0 || !S_ISDIR(st.st_mode) ||
directory_is_empty(srcpath))
{
/* Assume we can ignore it */
pfree(srcpath);
continue;
}
if (srctablespace == src_deftablespace)
dsttablespace = dst_deftablespace;
else
dsttablespace = srctablespace;
dstpath = GetDatabasePath(dboid, dsttablespace);
/*
* Copy this subdirectory to the new location
*
* We don't need to copy subdirectories
*/
copydir(srcpath, dstpath, false);
/* Record the filesystem change in XLOG */
{
xl_dbase_create_rec xlrec;
xlrec.db_id = dboid;
xlrec.tablespace_id = dsttablespace;
xlrec.src_db_id = src_dboid;
xlrec.src_tablespace_id = srctablespace;
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_create_rec));
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_CREATE | XLR_SPECIAL_REL_UPDATE);
}
}
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
table_endscan(scan);
table_close(rel, AccessShareLock);
2004-08-29 07:07:03 +02:00
/*
* We force a checkpoint before committing. This effectively means
* that committed XLOG_DBASE_CREATE operations will never need to be
2005-10-15 04:49:52 +02:00
* replayed (at least not in ordinary crash recovery; we still have to
* make the XLOG entry for the benefit of PITR operations). This
* avoids two nasty scenarios:
*
* #1: When PITR is off, we don't XLOG the contents of newly created
* indexes; therefore the drop-and-recreate-whole-directory behavior
* of DBASE_CREATE replay would lose such indexes.
*
* #2: Since we have to recopy the source database during DBASE_CREATE
2005-10-15 04:49:52 +02:00
* replay, we run the risk of copying changes in it that were
* committed after the original CREATE DATABASE command but before the
* system crash that led to the replay. This is at least unexpected
* and at worst could lead to inconsistencies, eg duplicate table
* names.
*
* (Both of these were real bugs in releases 8.0 through 8.0.3.)
*
* In PITR replay, the first of these isn't an issue, and the second
* is only a risk if the CREATE DATABASE and subsequent template
* database change both occur while a base backup is being taken.
* There doesn't seem to be much we can do about that except document
* it as a limitation.
*
* Perhaps if we ever implement CREATE DATABASE in a less cheesy way,
* we can avoid this.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Close pg_database, but keep lock till commit.
*/
table_close(pg_database_rel, NoLock);
/*
* Force synchronous commit, thus minimizing the window between
* creation of the database files and committal of the transaction. If
2007-11-15 22:14:46 +01:00
* we crash before committing, we'll have a DB that's taking up disk
* space but is not in pg_database, which is not good.
*/
ForceSyncCommit();
}
PG_END_ENSURE_ERROR_CLEANUP(createdb_failure_callback,
PointerGetDatum(&fparms));
return dboid;
}
/*
* Check whether chosen encoding matches chosen locale settings. This
* restriction is necessary because libc's locale-specific code usually
* fails when presented with data in an encoding it's not expecting. We
* allow mismatch in four cases:
*
* 1. locale encoding = SQL_ASCII, which means that the locale is C/POSIX
* which works with any encoding.
*
* 2. locale encoding = -1, which means that we couldn't determine the
* locale's encoding and have to trust the user to get it right.
*
* 3. selected encoding is UTF8 and platform is win32. This is because
* UTF8 is a pseudo codepage that is supported in all locales since it's
* converted to UTF16 before being used.
*
* 4. selected encoding is SQL_ASCII, but only if you're a superuser. This
* is risky but we have historically allowed it --- notably, the
* regression tests require it.
*
* Note: if you change this policy, fix initdb to match.
*/
void
check_encoding_locale_matches(int encoding, const char *collate, const char *ctype)
{
2011-04-10 17:42:00 +02:00
int ctype_encoding = pg_get_encoding_from_locale(ctype, true);
int collate_encoding = pg_get_encoding_from_locale(collate, true);
if (!(ctype_encoding == encoding ||
ctype_encoding == PG_SQL_ASCII ||
ctype_encoding == -1 ||
#ifdef WIN32
encoding == PG_UTF8 ||
#endif
(encoding == PG_SQL_ASCII && superuser())))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("encoding \"%s\" does not match locale \"%s\"",
pg_encoding_to_char(encoding),
ctype),
errdetail("The chosen LC_CTYPE setting requires encoding \"%s\".",
pg_encoding_to_char(ctype_encoding))));
if (!(collate_encoding == encoding ||
collate_encoding == PG_SQL_ASCII ||
collate_encoding == -1 ||
#ifdef WIN32
encoding == PG_UTF8 ||
#endif
(encoding == PG_SQL_ASCII && superuser())))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("encoding \"%s\" does not match locale \"%s\"",
pg_encoding_to_char(encoding),
collate),
errdetail("The chosen LC_COLLATE setting requires encoding \"%s\".",
pg_encoding_to_char(collate_encoding))));
}
/* Error cleanup callback for createdb */
static void
createdb_failure_callback(int code, Datum arg)
{
createdb_failure_params *fparms = (createdb_failure_params *) DatumGetPointer(arg);
/*
* Release lock on source database before doing recursive remove. This is
* not essential but it seems desirable to release the lock as soon as
* possible.
*/
UnlockSharedObject(DatabaseRelationId, fparms->src_dboid, 0, ShareLock);
/* Throw away any successfully copied subdirectories */
remove_dbtablespaces(fparms->dest_dboid);
}
/*
* DROP DATABASE
*/
void
2005-11-22 16:24:18 +01:00
dropdb(const char *dbname, bool missing_ok)
{
Oid db_id;
bool db_istemplate;
Relation pgdbrel;
HeapTuple tup;
int notherbackends;
int npreparedxacts;
int nslots,
nslots_active;
int nsubscriptions;
/*
2006-10-04 02:30:14 +02:00
* Look up the target database's OID, and get exclusive lock on it. We
* need this to ensure that no new backend starts up in the target
* database while we are deleting it (see postinit.c), and that no one is
* using it as a CREATE DATABASE template or trying to delete it for
* themselves.
*/
pgdbrel = table_open(DatabaseRelationId, RowExclusiveLock);
if (!get_db_info(dbname, AccessExclusiveLock, &db_id, NULL, NULL,
&db_istemplate, NULL, NULL, NULL, NULL, NULL, NULL, NULL))
2005-11-22 16:24:18 +01:00
{
if (!missing_ok)
2005-11-22 16:24:18 +01:00
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
2005-11-22 16:24:18 +01:00
}
else
{
/* Close pg_database, release the lock, since we changed nothing */
table_close(pgdbrel, RowExclusiveLock);
ereport(NOTICE,
(errmsg("database \"%s\" does not exist, skipping",
2005-11-22 16:24:18 +01:00
dbname)));
return;
}
}
/*
* Permission checks
*/
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/* DROP hook for the database being removed */
InvokeObjectDropHook(DatabaseRelationId, db_id, 0);
/*
2001-03-22 05:01:46 +01:00
* Disallow dropping a DB that is marked istemplate. This is just to
2005-10-15 04:49:52 +02:00
* prevent people from accidentally dropping template0 or template1; they
* can do so if they're really determined ...
*/
if (db_istemplate)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot drop a template database")));
/* Obviously can't drop my own database */
if (db_id == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot drop the currently open database")));
/*
* Check whether there are active logical slots that refer to the
* to-be-dropped database. The database lock we are holding prevents the
* creation of new slots using the database or existing slots becoming
* active.
*/
(void) ReplicationSlotsCountDBSlots(db_id, &nslots, &nslots_active);
if (nslots_active)
{
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is used by an active logical replication slot",
dbname),
2018-02-18 23:16:11 +01:00
errdetail_plural("There is %d active slot.",
"There are %d active slots.",
nslots_active, nslots_active)));
}
/*
* Check if there are subscriptions defined in the target database.
*
* We can't drop them automatically because they might be holding
* resources in other databases/instances.
*/
if ((nsubscriptions = CountDBSubscriptions(db_id)) > 0)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being used by logical replication subscription",
dbname),
errdetail_plural("There is %d subscription.",
"There are %d subscriptions.",
nsubscriptions, nsubscriptions)));
/*
* Check for other backends in the target database. (Because we hold the
* database lock, no new ones can start after this.)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
dbname),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Remove the database's tuple from pg_database.
*/
tup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(db_id));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for database %u", db_id);
CatalogTupleDelete(pgdbrel, &tup->t_self);
ReleaseSysCache(tup);
/*
* Delete any comments or security labels associated with the database.
*/
DeleteSharedComments(db_id, DatabaseRelationId);
DeleteSharedSecurityLabel(db_id, DatabaseRelationId);
/*
* Remove settings associated with this database
*/
DropSetting(db_id, InvalidOid);
/*
* Remove shared dependency references for the database.
*/
dropDatabaseDependencies(db_id);
/*
* Drop db-specific replication slots.
*/
ReplicationSlotsDropDBSlots(db_id);
/*
2005-10-15 04:49:52 +02:00
* Drop pages for this database that are in the shared buffer cache. This
* is important to ensure that no remaining backend tries to write out a
* dirty buffer to the dead database later...
*/
DropDatabaseBuffers(db_id);
/*
* Tell the stats collector to forget it immediately, too.
*/
pgstat_drop_database(db_id);
/*
* Tell checkpointer to forget any pending fsync and unlink requests for
* files in the database; else the fsyncs will fail at next checkpoint, or
* worse, it will delete files that belong to a newly created database
* with the same OID.
*/
ForgetDatabaseSyncRequests(db_id);
/*
* Force a checkpoint to make sure the checkpointer has received the
* message sent by ForgetDatabaseSyncRequests. On Windows, this also
* ensures that background procs don't hold any open files, which would
* cause rmdir() to fail.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Remove all tablespace subdirs belonging to the database.
*/
remove_dbtablespaces(db_id);
/*
* Close pg_database, but keep lock till commit.
*/
table_close(pgdbrel, NoLock);
/*
2010-02-26 03:01:40 +01:00
* Force synchronous commit, thus minimizing the window between removal of
* the database files and committal of the transaction. If we crash before
2010-02-26 03:01:40 +01:00
* committing, we'll have a DB that's gone on disk but still there
2007-11-15 22:14:46 +01:00
* according to pg_database, which is not good.
*/
ForceSyncCommit();
}
2003-06-27 16:45:32 +02:00
/*
* Rename database
*/
ObjectAddress
2003-06-27 16:45:32 +02:00
RenameDatabase(const char *oldname, const char *newname)
{
Oid db_id;
HeapTuple newtup;
2003-06-27 16:45:32 +02:00
Relation rel;
int notherbackends;
int npreparedxacts;
ObjectAddress address;
2003-06-27 16:45:32 +02:00
/*
2006-10-04 02:30:14 +02:00
* Look up the target database's OID, and get exclusive lock on it. We
* need this for the same reasons as DROP DATABASE.
2003-06-27 16:45:32 +02:00
*/
rel = table_open(DatabaseRelationId, RowExclusiveLock);
2003-06-27 16:45:32 +02:00
if (!get_db_info(oldname, AccessExclusiveLock, &db_id, NULL, NULL,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL))
2003-06-27 16:45:32 +02:00
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
2003-06-27 16:45:32 +02:00
errmsg("database \"%s\" does not exist", oldname)));
/* must be owner */
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
oldname);
/* must have createdb rights */
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to rename database")));
Add an enforcement mechanism for global object names in regression tests. In commit 18555b132 we tentatively established a rule that regression tests should use names containing "regression" for databases, and names starting with "regress_" for all other globally-visible object names, so as to circumscribe the side-effects that "make installcheck" could have on an existing installation. This commit adds a simple enforcement mechanism for that rule: if the code is compiled with ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS defined, it will emit a warning (not an error) whenever a database, role, tablespace, subscription, or replication origin name is created that doesn't obey the rule. Running one or more buildfarm members with that symbol defined should be enough to catch new violations, at least in the regular regression tests. Most TAP tests wouldn't notice such warnings, but that's actually fine because TAP tests don't execute against an existing server anyway. Since it's already the case that running src/test/modules/ tests in installcheck mode is deprecated, we can use that as a home for tests that seem unsafe to run against an existing server, such as tests that might have side-effects on existing roles. Document that (though this commit doesn't in itself make it any less safe than before). Update regress.sgml to define these restrictions more clearly, and to clean up assorted lack-of-up-to-date-ness in its descriptions of the available regression tests. Discussion: https://postgr.es/m/16638.1468620817@sss.pgh.pa.us
2019-06-29 17:34:00 +02:00
/*
* If built with appropriate switch, whine when regression-testing
* conventions for database names are violated.
*/
#ifdef ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS
if (strstr(newname, "regression") == NULL)
elog(WARNING, "databases created by regression test cases should have names including \"regression\"");
#endif
/*
* Make sure the new name doesn't exist. See notes for same error in
* CREATE DATABASE.
*/
if (OidIsValid(get_database_oid(newname, true)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_DATABASE),
errmsg("database \"%s\" already exists", newname)));
2003-06-27 16:45:32 +02:00
/*
2005-10-15 04:49:52 +02:00
* XXX Client applications probably store the current database somewhere,
* so renaming it could cause confusion. On the other hand, there may not
* be an actual problem besides a little confusion, so think about this
* and decide.
2003-06-27 16:45:32 +02:00
*/
if (db_id == MyDatabaseId)
2003-06-27 16:45:32 +02:00
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("current database cannot be renamed")));
2003-06-27 16:45:32 +02:00
/*
2006-10-04 02:30:14 +02:00
* Make sure the database does not have active sessions. This is the same
* concern as above, but applied to other sessions.
*
* As in CREATE DATABASE, check this after other error conditions.
2003-06-27 16:45:32 +02:00
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
2005-10-15 04:49:52 +02:00
errmsg("database \"%s\" is being accessed by other users",
oldname),
errdetail_busy_db(notherbackends, npreparedxacts)));
2003-06-27 16:45:32 +02:00
/* rename */
newtup = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(db_id));
if (!HeapTupleIsValid(newtup))
elog(ERROR, "cache lookup failed for database %u", db_id);
2003-06-27 16:45:32 +02:00
namestrcpy(&(((Form_pg_database) GETSTRUCT(newtup))->datname), newname);
CatalogTupleUpdate(rel, &newtup->t_self, newtup);
2003-06-27 16:45:32 +02:00
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
ObjectAddressSet(address, DatabaseRelationId, db_id);
/*
* Close pg_database, but keep lock till commit.
*/
table_close(rel, NoLock);
return address;
2003-06-27 16:45:32 +02:00
}
/*
* ALTER DATABASE SET TABLESPACE
*/
static void
movedb(const char *dbname, const char *tblspcname)
{
Oid db_id;
Relation pgdbrel;
int notherbackends;
int npreparedxacts;
HeapTuple oldtuple,
newtuple;
Oid src_tblspcoid,
dst_tblspcoid;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
bool new_record_repl[Natts_pg_database];
ScanKeyData scankey;
SysScanDesc sysscan;
AclResult aclresult;
char *src_dbpath;
char *dst_dbpath;
DIR *dstdir;
struct dirent *xlde;
movedb_failure_params fparms;
/*
* Look up the target database's OID, and get exclusive lock on it. We
* need this to ensure that no new backend starts up in the database while
* we are moving it, and that no one is using it as a CREATE DATABASE
* template or trying to delete it.
*/
pgdbrel = table_open(DatabaseRelationId, RowExclusiveLock);
if (!get_db_info(dbname, AccessExclusiveLock, &db_id, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, &src_tblspcoid, NULL, NULL))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
/*
* We actually need a session lock, so that the lock will persist across
* the commit/restart below. (We could almost get away with letting the
* lock be released at commit, except that someone could try to move
* relations of the DB back into the old directory while we rmtree() it.)
*/
LockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
/*
* Permission checks
*/
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/*
* Obviously can't move the tables of my own database
*/
if (db_id == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("cannot change the tablespace of the currently open database")));
/*
* Get tablespace's oid
*/
dst_tblspcoid = get_tablespace_oid(tblspcname, false);
/*
* Permission checks
*/
aclresult = pg_tablespace_aclcheck(dst_tblspcoid, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_TABLESPACE,
tblspcname);
/*
* pg_global must never be the default tablespace
*/
if (dst_tblspcoid == GLOBALTABLESPACE_OID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("pg_global cannot be used as default tablespace")));
/*
* No-op if same tablespace
*/
if (src_tblspcoid == dst_tblspcoid)
{
table_close(pgdbrel, NoLock);
UnlockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
return;
}
/*
* Check for other backends in the target database. (Because we hold the
* database lock, no new ones can start after this.)
*
* As in CREATE DATABASE, check this after other error conditions.
*/
if (CountOtherDBBackends(db_id, &notherbackends, &npreparedxacts))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("database \"%s\" is being accessed by other users",
dbname),
errdetail_busy_db(notherbackends, npreparedxacts)));
/*
* Get old and new database paths
*/
src_dbpath = GetDatabasePath(db_id, src_tblspcoid);
dst_dbpath = GetDatabasePath(db_id, dst_tblspcoid);
/*
* Force a checkpoint before proceeding. This will force all dirty
* buffers, including those of unlogged tables, out to disk, to ensure
* source database is up-to-date on disk for the copy.
* FlushDatabaseBuffers() would suffice for that, but we also want to
* process any pending unlink requests. Otherwise, the check for existing
* files in the target directory might fail unnecessarily, not to mention
* that the copy might fail due to source files getting deleted under it.
* On Windows, this also ensures that background procs don't hold any open
* files, which would cause rmdir() to fail.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT
| CHECKPOINT_FLUSH_ALL);
/*
* Now drop all buffers holding data of the target database; they should
* no longer be dirty so DropDatabaseBuffers is safe.
*
* It might seem that we could just let these buffers age out of shared
* buffers naturally, since they should not get referenced anymore. The
* problem with that is that if the user later moves the database back to
* its original tablespace, any still-surviving buffers would appear to
* contain valid data again --- but they'd be missing any changes made in
* the database while it was in the new tablespace. In any case, freeing
* buffers that should never be used again seems worth the cycles.
*
* Note: it'd be sufficient to get rid of buffers matching db_id and
* src_tblspcoid, but bufmgr.c presently provides no API for that.
*/
DropDatabaseBuffers(db_id);
/*
* Check for existence of files in the target directory, i.e., objects of
* this database that are already in the target tablespace. We can't
* allow the move in such a case, because we would need to change those
* relations' pg_class.reltablespace entries to zero, and we don't have
* access to the DB's pg_class to do so.
*/
dstdir = AllocateDir(dst_dbpath);
if (dstdir != NULL)
{
while ((xlde = ReadDir(dstdir, dst_dbpath)) != NULL)
{
if (strcmp(xlde->d_name, ".") == 0 ||
strcmp(xlde->d_name, "..") == 0)
continue;
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("some relations of database \"%s\" are already in tablespace \"%s\"",
dbname, tblspcname),
errhint("You must move them back to the database's default tablespace before using this command.")));
}
FreeDir(dstdir);
/*
* The directory exists but is empty. We must remove it before using
* the copydir function.
*/
if (rmdir(dst_dbpath) != 0)
elog(ERROR, "could not remove directory \"%s\": %m",
dst_dbpath);
}
/*
* Use an ENSURE block to make sure we remove the debris if the copy fails
* (eg, due to out-of-disk-space). This is not a 100% solution, because
* of the possibility of failure during transaction commit, but it should
* handle most scenarios.
*/
fparms.dest_dboid = db_id;
fparms.dest_tsoid = dst_tblspcoid;
PG_ENSURE_ERROR_CLEANUP(movedb_failure_callback,
PointerGetDatum(&fparms));
{
/*
* Copy files from the old tablespace to the new one
*/
copydir(src_dbpath, dst_dbpath, false);
/*
* Record the filesystem change in XLOG
*/
{
xl_dbase_create_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = dst_tblspcoid;
xlrec.src_db_id = db_id;
xlrec.src_tablespace_id = src_tblspcoid;
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_create_rec));
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_CREATE | XLR_SPECIAL_REL_UPDATE);
}
/*
* Update the database's pg_database tuple
*/
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
sysscan = systable_beginscan(pgdbrel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
oldtuple = systable_getnext(sysscan);
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
2017-06-21 21:18:54 +02:00
if (!HeapTupleIsValid(oldtuple)) /* shouldn't happen... */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
MemSet(new_record_repl, false, sizeof(new_record_repl));
new_record[Anum_pg_database_dattablespace - 1] = ObjectIdGetDatum(dst_tblspcoid);
new_record_repl[Anum_pg_database_dattablespace - 1] = true;
newtuple = heap_modify_tuple(oldtuple, RelationGetDescr(pgdbrel),
new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(pgdbrel, &oldtuple->t_self, newtuple);
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
systable_endscan(sysscan);
/*
* Force another checkpoint here. As in CREATE DATABASE, this is to
* ensure that we don't have to replay a committed XLOG_DBASE_CREATE
* operation, which would cause us to lose any unlogged operations
* done in the new DB tablespace before the next checkpoint.
*/
RequestCheckpoint(CHECKPOINT_IMMEDIATE | CHECKPOINT_FORCE | CHECKPOINT_WAIT);
/*
* Force synchronous commit, thus minimizing the window between
* copying the database files and committal of the transaction. If we
* crash before committing, we'll leave an orphaned set of files on
* disk, which is not fatal but not good either.
*/
ForceSyncCommit();
/*
* Close pg_database, but keep lock till commit.
*/
table_close(pgdbrel, NoLock);
}
PG_END_ENSURE_ERROR_CLEANUP(movedb_failure_callback,
PointerGetDatum(&fparms));
/*
* Commit the transaction so that the pg_database update is committed. If
* we crash while removing files, the database won't be corrupt, we'll
* just leave some orphaned files in the old directory.
*
* (This is OK because we know we aren't inside a transaction block.)
*
* XXX would it be safe/better to do this inside the ensure block? Not
* convinced it's a good idea; consider elog just after the transaction
* really commits.
*/
PopActiveSnapshot();
CommitTransactionCommand();
/* Start new transaction for the remaining work; don't need a snapshot */
StartTransactionCommand();
/*
* Remove files from the old tablespace
*/
if (!rmtree(src_dbpath, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
src_dbpath)));
/*
* Record the filesystem change in XLOG
*/
{
xl_dbase_drop_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = src_tblspcoid;
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_drop_rec));
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_DROP | XLR_SPECIAL_REL_UPDATE);
}
/* Now it's safe to release the database lock */
UnlockSharedObjectForSession(DatabaseRelationId, db_id, 0,
AccessExclusiveLock);
}
/* Error cleanup callback for movedb */
static void
movedb_failure_callback(int code, Datum arg)
{
movedb_failure_params *fparms = (movedb_failure_params *) DatumGetPointer(arg);
char *dstpath;
/* Get rid of anything we managed to copy to the target directory */
dstpath = GetDatabasePath(fparms->dest_dboid, fparms->dest_tsoid);
(void) rmtree(dstpath, true);
}
/*
* ALTER DATABASE name ...
*/
Oid
AlterDatabase(ParseState *pstate, AlterDatabaseStmt *stmt, bool isTopLevel)
{
Relation rel;
Oid dboid;
HeapTuple tuple,
newtuple;
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
Form_pg_database datform;
ScanKeyData scankey;
SysScanDesc scan;
ListCell *option;
bool dbistemplate = false;
bool dballowconnections = true;
int dbconnlimit = -1;
DefElem *distemplate = NULL;
DefElem *dallowconnections = NULL;
DefElem *dconnlimit = NULL;
DefElem *dtablespace = NULL;
Datum new_record[Natts_pg_database];
bool new_record_nulls[Natts_pg_database];
bool new_record_repl[Natts_pg_database];
/* Extract options from the statement node tree */
foreach(option, stmt->options)
{
DefElem *defel = (DefElem *) lfirst(option);
if (strcmp(defel->defname, "is_template") == 0)
{
if (distemplate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
distemplate = defel;
}
else if (strcmp(defel->defname, "allow_connections") == 0)
{
if (dallowconnections)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dallowconnections = defel;
}
else if (strcmp(defel->defname, "connection_limit") == 0)
{
if (dconnlimit)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dconnlimit = defel;
}
else if (strcmp(defel->defname, "tablespace") == 0)
{
if (dtablespace)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("conflicting or redundant options"),
parser_errposition(pstate, defel->location)));
dtablespace = defel;
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("option \"%s\" not recognized", defel->defname),
parser_errposition(pstate, defel->location)));
}
if (dtablespace)
{
/*
* While the SET TABLESPACE syntax doesn't allow any other options,
* somebody could write "WITH TABLESPACE ...". Forbid any other
* options from being specified in that case.
*/
if (list_length(stmt->options) != 1)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("option \"%s\" cannot be specified with other options",
dtablespace->defname),
parser_errposition(pstate, dtablespace->location)));
/* this case isn't allowed within a transaction block */
PreventInTransactionBlock(isTopLevel, "ALTER DATABASE SET TABLESPACE");
movedb(stmt->dbname, defGetString(dtablespace));
return InvalidOid;
}
if (distemplate && distemplate->arg)
dbistemplate = defGetBoolean(distemplate);
if (dallowconnections && dallowconnections->arg)
dballowconnections = defGetBoolean(dallowconnections);
if (dconnlimit && dconnlimit->arg)
{
dbconnlimit = defGetInt32(dconnlimit);
if (dbconnlimit < -1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid connection limit: %d", dbconnlimit)));
}
/*
* Get the old tuple. We don't need a lock on the database per se,
* because we're not going to do anything that would mess up incoming
* connections.
*/
rel = table_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(stmt->dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", stmt->dbname)));
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
datform = (Form_pg_database) GETSTRUCT(tuple);
dboid = datform->oid;
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
if (!pg_database_ownercheck(dboid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
stmt->dbname);
/*
* In order to avoid getting locked out and having to go through
* standalone mode, we refuse to disallow connections to the database
* we're currently connected to. Lockout can still happen with concurrent
* sessions but the likeliness of that is not high enough to worry about.
*/
if (!dballowconnections && dboid == MyDatabaseId)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("cannot disallow connections for current database")));
/*
* Build an updated tuple, perusing the information just obtained
*/
MemSet(new_record, 0, sizeof(new_record));
MemSet(new_record_nulls, false, sizeof(new_record_nulls));
MemSet(new_record_repl, false, sizeof(new_record_repl));
if (distemplate)
{
new_record[Anum_pg_database_datistemplate - 1] = BoolGetDatum(dbistemplate);
new_record_repl[Anum_pg_database_datistemplate - 1] = true;
}
if (dallowconnections)
{
new_record[Anum_pg_database_datallowconn - 1] = BoolGetDatum(dballowconnections);
new_record_repl[Anum_pg_database_datallowconn - 1] = true;
}
if (dconnlimit)
{
new_record[Anum_pg_database_datconnlimit - 1] = Int32GetDatum(dbconnlimit);
new_record_repl[Anum_pg_database_datconnlimit - 1] = true;
}
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel), new_record,
new_record_nulls, new_record_repl);
CatalogTupleUpdate(rel, &tuple->t_self, newtuple);
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
InvokeObjectPostAlterHook(DatabaseRelationId, dboid, 0);
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
table_close(rel, NoLock);
return dboid;
}
/*
* ALTER DATABASE name SET ...
*/
Oid
AlterDatabaseSet(AlterDatabaseSetStmt *stmt)
{
Oid datid = get_database_oid(stmt->dbname, false);
2010-02-26 03:01:40 +01:00
/*
* Obtain a lock on the database and make sure it didn't go away in the
* meantime.
*/
shdepLockAndCheckObject(DatabaseRelationId, datid);
if (!pg_database_ownercheck(datid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
2010-02-26 03:01:40 +01:00
stmt->dbname);
AlterSetting(datid, InvalidOid, stmt->setstmt);
2010-02-26 03:01:40 +01:00
UnlockSharedObject(DatabaseRelationId, datid, 0, AccessShareLock);
return datid;
}
/*
* ALTER DATABASE name OWNER TO newowner
*/
ObjectAddress
AlterDatabaseOwner(const char *dbname, Oid newOwnerId)
{
Oid db_id;
HeapTuple tuple;
Relation rel;
ScanKeyData scankey;
SysScanDesc scan;
2004-08-29 07:07:03 +02:00
Form_pg_database datForm;
ObjectAddress address;
/*
* Get the old tuple. We don't need a lock on the database per se,
* because we're not going to do anything that would mess up incoming
* connections.
*/
rel = table_open(DatabaseRelationId, RowExclusiveLock);
ScanKeyInit(&scankey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(rel, DatabaseNameIndexId, true,
NULL, 1, &scankey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist", dbname)));
datForm = (Form_pg_database) GETSTRUCT(tuple);
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
db_id = datForm->oid;
2004-08-29 07:07:03 +02:00
/*
* If the new owner is the same as the existing owner, consider the
2004-08-29 07:07:03 +02:00
* command to have succeeded. This is to be consistent with other
* objects.
*/
if (datForm->datdba != newOwnerId)
{
Datum repl_val[Natts_pg_database];
bool repl_null[Natts_pg_database];
bool repl_repl[Natts_pg_database];
2004-08-29 07:07:03 +02:00
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* Otherwise, must be owner of the existing object */
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
if (!pg_database_ownercheck(db_id, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE,
dbname);
/* Must be able to become new owner */
check_is_member_of_role(GetUserId(), newOwnerId);
/*
2005-10-15 04:49:52 +02:00
* must have createdb rights
*
2005-10-15 04:49:52 +02:00
* NOTE: This is different from other alter-owner checks in that the
* current user is checked for createdb privileges instead of the
* destination owner. This is consistent with the CREATE case for
* databases. Because superusers will always have this right, we need
* no special case for them.
*/
if (!have_createdb_privilege())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to change owner of database")));
memset(repl_null, false, sizeof(repl_null));
memset(repl_repl, false, sizeof(repl_repl));
repl_repl[Anum_pg_database_datdba - 1] = true;
repl_val[Anum_pg_database_datdba - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = heap_getattr(tuple,
2004-08-29 07:07:03 +02:00
Anum_pg_database_datacl,
RelationGetDescr(rel),
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
datForm->datdba, newOwnerId);
repl_repl[Anum_pg_database_datacl - 1] = true;
repl_val[Anum_pg_database_datacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modify_tuple(tuple, RelationGetDescr(rel), repl_val, repl_null, repl_repl);
CatalogTupleUpdate(rel, &newtuple->t_self, newtuple);
heap_freetuple(newtuple);
/* Update owner dependency reference */
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
changeDependencyOnOwner(DatabaseRelationId, db_id, newOwnerId);
}
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
InvokeObjectPostAlterHook(DatabaseRelationId, db_id, 0);
ObjectAddressSet(address, DatabaseRelationId, db_id);
systable_endscan(scan);
/* Close pg_database, but keep lock till commit */
table_close(rel, NoLock);
return address;
}
/*
* Helper functions
*/
/*
* Look up info about the database named "name". If the database exists,
* obtain the specified lock type on it, fill in any of the remaining
* parameters that aren't NULL, and return true. If no such database,
* return false.
*/
static bool
get_db_info(const char *name, LOCKMODE lockmode,
Oid *dbIdP, Oid *ownerIdP,
int *encodingP, bool *dbIsTemplateP, bool *dbAllowConnP,
Oid *dbLastSysOidP, TransactionId *dbFrozenXidP,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
MultiXactId *dbMinMultiP,
Oid *dbTablespace, char **dbCollate, char **dbCtype)
{
bool result = false;
Relation relation;
AssertArg(name);
/* Caller may wish to grab a better lock on pg_database beforehand... */
relation = table_open(DatabaseRelationId, AccessShareLock);
/*
2006-10-04 02:30:14 +02:00
* Loop covers the rare case where the database is renamed before we can
* lock it. We try again just in case we can find a new one of the same
* name.
*/
for (;;)
{
ScanKeyData scanKey;
SysScanDesc scan;
HeapTuple tuple;
Oid dbOid;
/*
2006-10-04 02:30:14 +02:00
* there's no syscache for database-indexed-by-name, so must do it the
* hard way
*/
ScanKeyInit(&scanKey,
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(name));
scan = systable_beginscan(relation, DatabaseNameIndexId, true,
NULL, 1, &scanKey);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
{
/* definitely no database of that name */
systable_endscan(scan);
break;
}
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
dbOid = ((Form_pg_database) GETSTRUCT(tuple))->oid;
systable_endscan(scan);
/*
* Now that we have a database OID, we can try to lock the DB.
*/
if (lockmode != NoLock)
LockSharedObject(DatabaseRelationId, dbOid, 0, lockmode);
/*
* And now, re-fetch the tuple by OID. If it's still there and still
2006-10-04 02:30:14 +02:00
* the same name, we win; else, drop the lock and loop back to try
* again.
*/
tuple = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(dbOid));
if (HeapTupleIsValid(tuple))
{
Form_pg_database dbform = (Form_pg_database) GETSTRUCT(tuple);
if (strcmp(name, NameStr(dbform->datname)) == 0)
{
/* oid of the database */
if (dbIdP)
*dbIdP = dbOid;
/* oid of the owner */
if (ownerIdP)
*ownerIdP = dbform->datdba;
/* character encoding */
if (encodingP)
*encodingP = dbform->encoding;
/* allowed as template? */
if (dbIsTemplateP)
*dbIsTemplateP = dbform->datistemplate;
/* allowing connections? */
if (dbAllowConnP)
*dbAllowConnP = dbform->datallowconn;
/* last system OID used in database */
if (dbLastSysOidP)
*dbLastSysOidP = dbform->datlastsysoid;
/* limit of frozen XIDs */
if (dbFrozenXidP)
*dbFrozenXidP = dbform->datfrozenxid;
/* minimum MultiXactId */
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
if (dbMinMultiP)
*dbMinMultiP = dbform->datminmxid;
/* default tablespace for this database */
if (dbTablespace)
*dbTablespace = dbform->dattablespace;
/* default locale settings for this database */
if (dbCollate)
*dbCollate = pstrdup(NameStr(dbform->datcollate));
if (dbCtype)
*dbCtype = pstrdup(NameStr(dbform->datctype));
ReleaseSysCache(tuple);
result = true;
break;
}
/* can only get here if it was just renamed */
ReleaseSysCache(tuple);
}
if (lockmode != NoLock)
UnlockSharedObject(DatabaseRelationId, dbOid, 0, lockmode);
}
table_close(relation, AccessShareLock);
return result;
}
/* Check if current user has createdb privileges */
static bool
have_createdb_privilege(void)
{
bool result = false;
HeapTuple utup;
/* Superusers can always do everything */
if (superuser())
return true;
utup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(GetUserId()));
if (HeapTupleIsValid(utup))
{
result = ((Form_pg_authid) GETSTRUCT(utup))->rolcreatedb;
ReleaseSysCache(utup);
}
return result;
}
/*
* Remove tablespace directories
*
* We don't know what tablespaces db_id is using, so iterate through all
* tablespaces removing <tablespace>/db_id
*/
static void
remove_dbtablespaces(Oid db_id)
{
2004-08-29 07:07:03 +02:00
Relation rel;
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
TableScanDesc scan;
2004-08-29 07:07:03 +02:00
HeapTuple tuple;
rel = table_open(TableSpaceRelationId, AccessShareLock);
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
scan = table_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
Form_pg_tablespace spcform = (Form_pg_tablespace) GETSTRUCT(tuple);
Oid dsttablespace = spcform->oid;
2004-08-29 07:07:03 +02:00
char *dstpath;
struct stat st;
/* Don't mess with the global tablespace */
if (dsttablespace == GLOBALTABLESPACE_OID)
continue;
dstpath = GetDatabasePath(db_id, dsttablespace);
if (lstat(dstpath, &st) < 0 || !S_ISDIR(st.st_mode))
{
/* Assume we can ignore it */
pfree(dstpath);
continue;
}
2004-08-01 08:19:26 +02:00
if (!rmtree(dstpath, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dstpath)));
/* Record the filesystem change in XLOG */
{
xl_dbase_drop_rec xlrec;
xlrec.db_id = db_id;
xlrec.tablespace_id = dsttablespace;
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_dbase_drop_rec));
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
(void) XLogInsert(RM_DBASE_ID,
XLOG_DBASE_DROP | XLR_SPECIAL_REL_UPDATE);
}
pfree(dstpath);
}
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
table_endscan(scan);
table_close(rel, AccessShareLock);
}
/*
* Check for existing files that conflict with a proposed new DB OID;
* return true if there are any
*
* If there were a subdirectory in any tablespace matching the proposed new
* OID, we'd get a create failure due to the duplicate name ... and then we'd
* try to remove that already-existing subdirectory during the cleanup in
* remove_dbtablespaces. Nuking existing files seems like a bad idea, so
* instead we make this extra check before settling on the OID of the new
* database. This exactly parallels what GetNewRelFileNode() does for table
* relfilenode values.
*/
static bool
check_db_file_conflict(Oid db_id)
{
bool result = false;
Relation rel;
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
TableScanDesc scan;
HeapTuple tuple;
rel = table_open(TableSpaceRelationId, AccessShareLock);
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
scan = table_beginscan_catalog(rel, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
Remove WITH OIDS support, change oid catalog column visibility. Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-21 00:36:57 +01:00
Form_pg_tablespace spcform = (Form_pg_tablespace) GETSTRUCT(tuple);
Oid dsttablespace = spcform->oid;
char *dstpath;
struct stat st;
/* Don't mess with the global tablespace */
if (dsttablespace == GLOBALTABLESPACE_OID)
continue;
dstpath = GetDatabasePath(db_id, dsttablespace);
if (lstat(dstpath, &st) == 0)
{
/* Found a conflicting file (or directory, whatever) */
pfree(dstpath);
result = true;
break;
}
pfree(dstpath);
}
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
table_endscan(scan);
table_close(rel, AccessShareLock);
return result;
}
/*
* Issue a suitable errdetail message for a busy database
*/
static int
errdetail_busy_db(int notherbackends, int npreparedxacts)
{
if (notherbackends > 0 && npreparedxacts > 0)
/*
* We don't deal with singular versus plural here, since gettext
* doesn't support multiple plurals in one string.
*/
errdetail("There are %d other session(s) and %d prepared transaction(s) using the database.",
notherbackends, npreparedxacts);
else if (notherbackends > 0)
errdetail_plural("There is %d other session using the database.",
"There are %d other sessions using the database.",
notherbackends,
notherbackends);
else
errdetail_plural("There is %d prepared transaction using the database.",
"There are %d prepared transactions using the database.",
npreparedxacts,
npreparedxacts);
return 0; /* just to keep ereport macro happy */
}
/*
* get_database_oid - given a database name, look up the OID
*
* If missing_ok is false, throw an error if database name not found. If
* true, just return InvalidOid.
*/
Oid
get_database_oid(const char *dbname, bool missing_ok)
{
Relation pg_database;
ScanKeyData entry[1];
2003-08-04 02:43:34 +02:00
SysScanDesc scan;
HeapTuple dbtuple;
Oid oid;
/*
2006-10-04 02:30:14 +02:00
* There's no syscache for pg_database indexed by name, so we must look
* the hard way.
*/
pg_database = table_open(DatabaseRelationId, AccessShareLock);
ScanKeyInit(&entry[0],
Anum_pg_database_datname,
BTEqualStrategyNumber, F_NAMEEQ,
CStringGetDatum(dbname));
scan = systable_beginscan(pg_database, DatabaseNameIndexId, true,
NULL, 1, entry);
2003-06-27 16:45:32 +02:00
dbtuple = systable_getnext(scan);
/* We assume that there can be at most one matching tuple */
if (HeapTupleIsValid(dbtuple))
oid = ((Form_pg_database) GETSTRUCT(dbtuple))->oid;
else
oid = InvalidOid;
2003-06-27 16:45:32 +02:00
systable_endscan(scan);
table_close(pg_database, AccessShareLock);
if (!OidIsValid(oid) && !missing_ok)
2011-04-10 17:42:00 +02:00
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_DATABASE),
errmsg("database \"%s\" does not exist",
dbname)));
return oid;
}
2003-06-27 16:45:32 +02:00
/*
2003-06-27 16:45:32 +02:00
* get_database_name - given a database OID, look up the name
*
* Returns a palloc'd string, or NULL if no such database.
*/
2003-06-27 16:45:32 +02:00
char *
get_database_name(Oid dbid)
{
HeapTuple dbtuple;
2003-06-27 16:45:32 +02:00
char *result;
dbtuple = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(dbid));
2003-06-27 16:45:32 +02:00
if (HeapTupleIsValid(dbtuple))
{
2003-06-27 16:45:32 +02:00
result = pstrdup(NameStr(((Form_pg_database) GETSTRUCT(dbtuple))->datname));
ReleaseSysCache(dbtuple);
}
2003-06-27 16:45:32 +02:00
else
result = NULL;
2003-06-27 16:45:32 +02:00
return result;
}
/*
* DATABASE resource manager's routines
*/
void
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
dbase_redo(XLogReaderState *record)
{
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
uint8 info = XLogRecGetInfo(record) & ~XLR_INFO_MASK;
/* Backup blocks are not used in dbase records */
Revamp the WAL record format. Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
2014-11-20 16:56:26 +01:00
Assert(!XLogRecHasAnyBlockRefs(record));
if (info == XLOG_DBASE_CREATE)
{
xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) XLogRecGetData(record);
char *src_path;
char *dst_path;
struct stat st;
src_path = GetDatabasePath(xlrec->src_db_id, xlrec->src_tablespace_id);
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
/*
2005-10-15 04:49:52 +02:00
* Our theory for replaying a CREATE is to forcibly drop the target
* subdirectory if present, then re-copy the source data. This may be
* more work than needed, but it is simple to implement.
*/
if (stat(dst_path, &st) == 0 && S_ISDIR(st.st_mode))
{
if (!rmtree(dst_path, true))
/* If this failed, copydir() below is going to error. */
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dst_path)));
}
/*
* Force dirty buffers out to disk, to ensure source database is
* up-to-date for the copy.
*/
FlushDatabaseBuffers(xlrec->src_db_id);
/*
* Copy this subdirectory to the new location
*
* We don't need to copy subdirectories
*/
copydir(src_path, dst_path, false);
}
else if (info == XLOG_DBASE_DROP)
{
xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) XLogRecGetData(record);
char *dst_path;
dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
if (InHotStandby)
{
/*
2010-02-26 03:01:40 +01:00
* Lock database while we resolve conflicts to ensure that
* InitPostgres() cannot fully re-execute concurrently. This
* avoids backends re-connecting automatically to same database,
* which can happen in some cases.
*
* This will lock out walsenders trying to connect to db-specific
* slots for logical decoding too, so it's safe for us to drop
* slots.
*/
LockSharedObjectForSession(DatabaseRelationId, xlrec->db_id, 0, AccessExclusiveLock);
ResolveRecoveryConflictWithDatabase(xlrec->db_id);
}
Allow read only connections during recovery, known as Hot Standby. Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record. New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far. This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required. Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit. Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.
2009-12-19 02:32:45 +01:00
/* Drop any database-specific replication slots */
ReplicationSlotsDropDBSlots(xlrec->db_id);
/* Drop pages for this database that are in the shared buffer cache */
DropDatabaseBuffers(xlrec->db_id);
/* Also, clean out any fsync requests that might be pending in md.c */
ForgetDatabaseSyncRequests(xlrec->db_id);
/* Clean out the xlog relcache too */
XLogDropDatabase(xlrec->db_id);
/* And remove the physical files */
if (!rmtree(dst_path, true))
ereport(WARNING,
(errmsg("some useless files may be left behind in old database directory \"%s\"",
dst_path)));
if (InHotStandby)
{
/*
2010-02-26 03:01:40 +01:00
* Release locks prior to commit. XXX There is a race condition
* here that may allow backends to reconnect, but the window for
* this is small because the gap between here and commit is mostly
* fairly small and it is unlikely that people will be dropping
* databases that we are trying to connect to anyway.
*/
UnlockSharedObjectForSession(DatabaseRelationId, xlrec->db_id, 0, AccessExclusiveLock);
}
}
else
elog(PANIC, "dbase_redo: unknown op code %u", info);
}