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postgresql/src/backend/catalog/heap.c

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/*-------------------------------------------------------------------------
*
* heap.c
* code to create and destroy POSTGRES heap relations
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.319 2007/05/11 17:57:11 tgl Exp $
*
*
* INTERFACE ROUTINES
* heap_create() - Create an uncataloged heap relation
* heap_create_with_catalog() - Create a cataloged relation
* heap_drop_with_catalog() - Removes named relation from catalogs
*
* NOTES
* this code taken from access/heap/create.c, which contains
* the old heap_create_with_catalog, amcreate, and amdestroy.
* those routines will soon call these routines using the function
* manager,
* just like the poorly named "NewXXX" routines do. The
* "New" routines are all going to die soon, once and for all!
* -cim 1/13/91
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_type.h"
#include "commands/tablecmds.h"
#include "commands/typecmds.h"
#include "miscadmin.h"
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "storage/smgr.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
static void AddNewRelationTuple(Relation pg_class_desc,
Relation new_rel_desc,
Oid new_rel_oid, Oid new_type_oid,
Oid relowner,
char relkind,
Datum reloptions);
static Oid AddNewRelationType(const char *typeName,
Oid typeNamespace,
Oid new_rel_oid,
char new_rel_kind,
Oid new_array_type);
static void RelationRemoveInheritance(Oid relid);
static void StoreRelCheck(Relation rel, char *ccname, char *ccbin);
static void StoreConstraints(Relation rel, TupleDesc tupdesc);
static void SetRelationNumChecks(Relation rel, int numchecks);
static List *insert_ordered_unique_oid(List *list, Oid datum);
/* ----------------------------------------------------------------
* XXX UGLY HARD CODED BADNESS FOLLOWS XXX
*
* these should all be moved to someplace in the lib/catalog
* module, if not obliterated first.
* ----------------------------------------------------------------
*/
/*
* Note:
* Should the system special case these attributes in the future?
* Advantage: consume much less space in the ATTRIBUTE relation.
* Disadvantage: special cases will be all over the place.
*/
static FormData_pg_attribute a1 = {
0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
SelfItemPointerAttributeNumber, 0, -1, -1,
false, 'p', 's', true, false, false, true, 0
};
static FormData_pg_attribute a2 = {
0, {"oid"}, OIDOID, 0, sizeof(Oid),
ObjectIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a3 = {
0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
MinTransactionIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a4 = {
0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
MinCommandIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a5 = {
0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
MaxTransactionIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static FormData_pg_attribute a6 = {
0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
MaxCommandIdAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
/*
* We decided to call this attribute "tableoid" rather than say
* "classoid" on the basis that in the future there may be more than one
* table of a particular class/type. In any case table is still the word
* used in SQL.
*/
static FormData_pg_attribute a7 = {
0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
TableOidAttributeNumber, 0, -1, -1,
true, 'p', 'i', true, false, false, true, 0
};
static const Form_pg_attribute SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6, &a7};
/*
* This function returns a Form_pg_attribute pointer for a system attribute.
* Note that we elog if the presented attno is invalid, which would only
* happen if there's a problem upstream.
*/
Form_pg_attribute
SystemAttributeDefinition(AttrNumber attno, bool relhasoids)
{
if (attno >= 0 || attno < -(int) lengthof(SysAtt))
elog(ERROR, "invalid system attribute number %d", attno);
if (attno == ObjectIdAttributeNumber && !relhasoids)
elog(ERROR, "invalid system attribute number %d", attno);
return SysAtt[-attno - 1];
}
/*
* If the given name is a system attribute name, return a Form_pg_attribute
* pointer for a prototype definition. If not, return NULL.
*/
Form_pg_attribute
SystemAttributeByName(const char *attname, bool relhasoids)
{
int j;
for (j = 0; j < (int) lengthof(SysAtt); j++)
{
Form_pg_attribute att = SysAtt[j];
if (relhasoids || att->attnum != ObjectIdAttributeNumber)
{
if (strcmp(NameStr(att->attname), attname) == 0)
return att;
}
}
return NULL;
}
/* ----------------------------------------------------------------
* XXX END OF UGLY HARD CODED BADNESS XXX
* ---------------------------------------------------------------- */
/* ----------------------------------------------------------------
* heap_create - Create an uncataloged heap relation
*
* Note API change: the caller must now always provide the OID
* to use for the relation.
*
* rel->rd_rel is initialized by RelationBuildLocalRelation,
* and is mostly zeroes at return.
* ----------------------------------------------------------------
*/
Relation
heap_create(const char *relname,
Oid relnamespace,
Oid reltablespace,
Oid relid,
TupleDesc tupDesc,
char relkind,
bool shared_relation,
bool allow_system_table_mods)
{
bool create_storage;
Relation rel;
/* The caller must have provided an OID for the relation. */
Assert(OidIsValid(relid));
/*
* sanity checks
*/
if (!allow_system_table_mods &&
(IsSystemNamespace(relnamespace) || IsToastNamespace(relnamespace)) &&
IsNormalProcessingMode())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied to create \"%s.%s\"",
get_namespace_name(relnamespace), relname),
errdetail("System catalog modifications are currently disallowed.")));
/*
* Decide if we need storage or not, and handle a couple other special
* cases for particular relkinds.
*/
switch (relkind)
{
case RELKIND_VIEW:
case RELKIND_COMPOSITE_TYPE:
create_storage = false;
/*
* Force reltablespace to zero if the relation has no physical
* storage. This is mainly just for cleanliness' sake.
*/
reltablespace = InvalidOid;
break;
case RELKIND_SEQUENCE:
create_storage = true;
/*
* Force reltablespace to zero for sequences, since we don't
* support moving them around into different tablespaces.
*/
reltablespace = InvalidOid;
break;
default:
create_storage = true;
break;
}
/*
* Never allow a pg_class entry to explicitly specify the database's
* default tablespace in reltablespace; force it to zero instead. This
* ensures that if the database is cloned with a different default
* tablespace, the pg_class entry will still match where CREATE DATABASE
* will put the physically copied relation.
*
* Yes, this is a bit of a hack.
*/
if (reltablespace == MyDatabaseTableSpace)
reltablespace = InvalidOid;
/*
* build the relcache entry.
*/
rel = RelationBuildLocalRelation(relname,
relnamespace,
tupDesc,
relid,
reltablespace,
shared_relation);
/*
* have the storage manager create the relation's disk file, if needed.
*/
if (create_storage)
{
Assert(rel->rd_smgr == NULL);
RelationOpenSmgr(rel);
smgrcreate(rel->rd_smgr, rel->rd_istemp, false);
}
return rel;
}
/* ----------------------------------------------------------------
* heap_create_with_catalog - Create a cataloged relation
*
* this is done in multiple steps:
*
* 1) CheckAttributeNamesTypes() is used to make certain the tuple
* descriptor contains a valid set of attribute names and types
*
* 2) pg_class is opened and get_relname_relid()
* performs a scan to ensure that no relation with the
* same name already exists.
*
* 3) heap_create() is called to create the new relation on disk.
*
* 4) TypeCreate() is called to define a new type corresponding
* to the new relation.
*
* 5) AddNewRelationTuple() is called to register the
* relation in pg_class.
*
* 6) AddNewAttributeTuples() is called to register the
* new relation's schema in pg_attribute.
*
* 7) StoreConstraints is called () - vadim 08/22/97
*
* 8) the relations are closed and the new relation's oid
* is returned.
*
* ----------------------------------------------------------------
*/
/* --------------------------------
* CheckAttributeNamesTypes
*
* this is used to make certain the tuple descriptor contains a
* valid set of attribute names and datatypes. a problem simply
* generates ereport(ERROR) which aborts the current transaction.
* --------------------------------
*/
void
CheckAttributeNamesTypes(TupleDesc tupdesc, char relkind)
{
int i;
int j;
int natts = tupdesc->natts;
/* Sanity check on column count */
if (natts < 0 || natts > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
/*
* first check for collision with system attribute names
*
* Skip this for a view or type relation, since those don't have system
* attributes.
*/
if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
{
for (i = 0; i < natts; i++)
{
if (SystemAttributeByName(NameStr(tupdesc->attrs[i]->attname),
tupdesc->tdhasoid) != NULL)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column name \"%s\" conflicts with a system column name",
NameStr(tupdesc->attrs[i]->attname))));
}
}
/*
* next check for repeated attribute names
*/
for (i = 1; i < natts; i++)
{
for (j = 0; j < i; j++)
{
if (strcmp(NameStr(tupdesc->attrs[j]->attname),
NameStr(tupdesc->attrs[i]->attname)) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column name \"%s\" is duplicated",
NameStr(tupdesc->attrs[j]->attname))));
}
}
/*
* next check the attribute types
*/
for (i = 0; i < natts; i++)
{
CheckAttributeType(NameStr(tupdesc->attrs[i]->attname),
tupdesc->attrs[i]->atttypid);
}
}
/* --------------------------------
* CheckAttributeType
*
* Verify that the proposed datatype of an attribute is legal.
* This is needed because there are types (and pseudo-types)
* in the catalogs that we do not support as elements of real tuples.
* --------------------------------
*/
void
CheckAttributeType(const char *attname, Oid atttypid)
{
char att_typtype = get_typtype(atttypid);
if (atttypid == UNKNOWNOID)
{
/*
* Warn user, but don't fail, if column to be created has UNKNOWN type
* (usually as a result of a 'retrieve into' - jolly)
*/
ereport(WARNING,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" has type \"unknown\"", attname),
errdetail("Proceeding with relation creation anyway.")));
}
else if (att_typtype == TYPTYPE_PSEUDO)
{
/*
* Refuse any attempt to create a pseudo-type column, except for
* a special hack for pg_statistic: allow ANYARRAY during initdb
*/
if (atttypid != ANYARRAYOID || IsUnderPostmaster)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" has pseudo-type %s",
attname, format_type_be(atttypid))));
}
else if (att_typtype == TYPTYPE_COMPOSITE)
{
/*
* For a composite type, recurse into its attributes. You might
* think this isn't necessary, but since we allow system catalogs
* to break the rule, we have to guard against the case.
*/
Relation relation;
TupleDesc tupdesc;
int i;
relation = relation_open(get_typ_typrelid(atttypid), AccessShareLock);
tupdesc = RelationGetDescr(relation);
for (i = 0; i < tupdesc->natts; i++)
{
Form_pg_attribute attr = tupdesc->attrs[i];
if (attr->attisdropped)
continue;
CheckAttributeType(NameStr(attr->attname), attr->atttypid);
}
relation_close(relation, AccessShareLock);
}
}
/* --------------------------------
* AddNewAttributeTuples
*
* this registers the new relation's schema by adding
* tuples to pg_attribute.
* --------------------------------
*/
static void
AddNewAttributeTuples(Oid new_rel_oid,
TupleDesc tupdesc,
char relkind,
bool oidislocal,
int oidinhcount)
{
const Form_pg_attribute *dpp;
int i;
HeapTuple tup;
Relation rel;
CatalogIndexState indstate;
int natts = tupdesc->natts;
ObjectAddress myself,
referenced;
/*
* open pg_attribute and its indexes.
*/
rel = heap_open(AttributeRelationId, RowExclusiveLock);
indstate = CatalogOpenIndexes(rel);
/*
* First we add the user attributes. This is also a convenient place to
* add dependencies on their datatypes.
*/
dpp = tupdesc->attrs;
for (i = 0; i < natts; i++)
{
/* Fill in the correct relation OID */
(*dpp)->attrelid = new_rel_oid;
/* Make sure these are OK, too */
(*dpp)->attstattarget = -1;
(*dpp)->attcacheoff = -1;
tup = heap_addheader(Natts_pg_attribute,
false,
ATTRIBUTE_TUPLE_SIZE,
(void *) *dpp);
simple_heap_insert(rel, tup);
CatalogIndexInsert(indstate, tup);
heap_freetuple(tup);
myself.classId = RelationRelationId;
myself.objectId = new_rel_oid;
myself.objectSubId = i + 1;
referenced.classId = TypeRelationId;
referenced.objectId = (*dpp)->atttypid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
dpp++;
}
/*
* Next we add the system attributes. Skip OID if rel has no OIDs. Skip
* all for a view or type relation. We don't bother with making datatype
* dependencies here, since presumably all these types are pinned.
*/
if (relkind != RELKIND_VIEW && relkind != RELKIND_COMPOSITE_TYPE)
{
dpp = SysAtt;
for (i = 0; i < -1 - FirstLowInvalidHeapAttributeNumber; i++)
{
if (tupdesc->tdhasoid ||
(*dpp)->attnum != ObjectIdAttributeNumber)
{
Form_pg_attribute attStruct;
tup = heap_addheader(Natts_pg_attribute,
false,
ATTRIBUTE_TUPLE_SIZE,
(void *) *dpp);
attStruct = (Form_pg_attribute) GETSTRUCT(tup);
/* Fill in the correct relation OID in the copied tuple */
attStruct->attrelid = new_rel_oid;
/* Fill in correct inheritance info for the OID column */
if (attStruct->attnum == ObjectIdAttributeNumber)
{
attStruct->attislocal = oidislocal;
attStruct->attinhcount = oidinhcount;
}
/*
* Unneeded since they should be OK in the constant data
* anyway
*/
/* attStruct->attstattarget = 0; */
/* attStruct->attcacheoff = -1; */
simple_heap_insert(rel, tup);
CatalogIndexInsert(indstate, tup);
heap_freetuple(tup);
}
dpp++;
}
}
/*
* clean up
*/
CatalogCloseIndexes(indstate);
heap_close(rel, RowExclusiveLock);
}
/* --------------------------------
* InsertPgClassTuple
*
* Construct and insert a new tuple in pg_class.
*
* Caller has already opened and locked pg_class.
* Tuple data is taken from new_rel_desc->rd_rel, except for the
* variable-width fields which are not present in a cached reldesc.
* We always initialize relacl to NULL (i.e., default permissions),
* and reloptions is set to the passed-in text array (if any).
* --------------------------------
*/
void
InsertPgClassTuple(Relation pg_class_desc,
Relation new_rel_desc,
Oid new_rel_oid,
Datum reloptions)
{
Form_pg_class rd_rel = new_rel_desc->rd_rel;
Datum values[Natts_pg_class];
char nulls[Natts_pg_class];
HeapTuple tup;
/* This is a tad tedious, but way cleaner than what we used to do... */
memset(values, 0, sizeof(values));
memset(nulls, ' ', sizeof(nulls));
values[Anum_pg_class_relname - 1] = NameGetDatum(&rd_rel->relname);
values[Anum_pg_class_relnamespace - 1] = ObjectIdGetDatum(rd_rel->relnamespace);
values[Anum_pg_class_reltype - 1] = ObjectIdGetDatum(rd_rel->reltype);
values[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(rd_rel->relowner);
values[Anum_pg_class_relam - 1] = ObjectIdGetDatum(rd_rel->relam);
values[Anum_pg_class_relfilenode - 1] = ObjectIdGetDatum(rd_rel->relfilenode);
values[Anum_pg_class_reltablespace - 1] = ObjectIdGetDatum(rd_rel->reltablespace);
values[Anum_pg_class_relpages - 1] = Int32GetDatum(rd_rel->relpages);
values[Anum_pg_class_reltuples - 1] = Float4GetDatum(rd_rel->reltuples);
values[Anum_pg_class_reltoastrelid - 1] = ObjectIdGetDatum(rd_rel->reltoastrelid);
values[Anum_pg_class_reltoastidxid - 1] = ObjectIdGetDatum(rd_rel->reltoastidxid);
values[Anum_pg_class_relhasindex - 1] = BoolGetDatum(rd_rel->relhasindex);
values[Anum_pg_class_relisshared - 1] = BoolGetDatum(rd_rel->relisshared);
values[Anum_pg_class_relkind - 1] = CharGetDatum(rd_rel->relkind);
values[Anum_pg_class_relnatts - 1] = Int16GetDatum(rd_rel->relnatts);
values[Anum_pg_class_relchecks - 1] = Int16GetDatum(rd_rel->relchecks);
values[Anum_pg_class_reltriggers - 1] = Int16GetDatum(rd_rel->reltriggers);
values[Anum_pg_class_relukeys - 1] = Int16GetDatum(rd_rel->relukeys);
values[Anum_pg_class_relfkeys - 1] = Int16GetDatum(rd_rel->relfkeys);
values[Anum_pg_class_relrefs - 1] = Int16GetDatum(rd_rel->relrefs);
values[Anum_pg_class_relhasoids - 1] = BoolGetDatum(rd_rel->relhasoids);
values[Anum_pg_class_relhaspkey - 1] = BoolGetDatum(rd_rel->relhaspkey);
values[Anum_pg_class_relhasrules - 1] = BoolGetDatum(rd_rel->relhasrules);
values[Anum_pg_class_relhassubclass - 1] = BoolGetDatum(rd_rel->relhassubclass);
values[Anum_pg_class_relfrozenxid - 1] = TransactionIdGetDatum(rd_rel->relfrozenxid);
/* start out with empty permissions */
nulls[Anum_pg_class_relacl - 1] = 'n';
if (reloptions != (Datum) 0)
values[Anum_pg_class_reloptions - 1] = reloptions;
else
nulls[Anum_pg_class_reloptions - 1] = 'n';
tup = heap_formtuple(RelationGetDescr(pg_class_desc), values, nulls);
/*
* The new tuple must have the oid already chosen for the rel. Sure would
* be embarrassing to do this sort of thing in polite company.
*/
HeapTupleSetOid(tup, new_rel_oid);
/* finally insert the new tuple, update the indexes, and clean up */
simple_heap_insert(pg_class_desc, tup);
CatalogUpdateIndexes(pg_class_desc, tup);
heap_freetuple(tup);
}
/* --------------------------------
* AddNewRelationTuple
*
* this registers the new relation in the catalogs by
* adding a tuple to pg_class.
* --------------------------------
*/
static void
AddNewRelationTuple(Relation pg_class_desc,
Relation new_rel_desc,
Oid new_rel_oid,
Oid new_type_oid,
Oid relowner,
char relkind,
Datum reloptions)
{
Form_pg_class new_rel_reltup;
/*
* first we update some of the information in our uncataloged relation's
* relation descriptor.
*/
new_rel_reltup = new_rel_desc->rd_rel;
switch (relkind)
{
case RELKIND_RELATION:
case RELKIND_INDEX:
case RELKIND_TOASTVALUE:
/* The relation is real, but as yet empty */
new_rel_reltup->relpages = 0;
new_rel_reltup->reltuples = 0;
break;
case RELKIND_SEQUENCE:
/* Sequences always have a known size */
new_rel_reltup->relpages = 1;
new_rel_reltup->reltuples = 1;
break;
default:
/* Views, etc, have no disk storage */
new_rel_reltup->relpages = 0;
new_rel_reltup->reltuples = 0;
break;
}
/* Initialize relfrozenxid */
if (relkind == RELKIND_RELATION ||
relkind == RELKIND_TOASTVALUE)
{
/*
* Initialize to the minimum XID that could put tuples in the table.
* We know that no xacts older than RecentXmin are still running,
* so that will do.
*/
if (!IsBootstrapProcessingMode())
new_rel_reltup->relfrozenxid = RecentXmin;
else
new_rel_reltup->relfrozenxid = FirstNormalTransactionId;
}
else
{
/*
* Other relation types will not contain XIDs, so set relfrozenxid
* to InvalidTransactionId. (Note: a sequence does contain a tuple,
* but we force its xmin to be FrozenTransactionId always; see
* commands/sequence.c.)
*/
new_rel_reltup->relfrozenxid = InvalidTransactionId;
}
new_rel_reltup->relowner = relowner;
new_rel_reltup->reltype = new_type_oid;
new_rel_reltup->relkind = relkind;
new_rel_desc->rd_att->tdtypeid = new_type_oid;
/* Now build and insert the tuple */
InsertPgClassTuple(pg_class_desc, new_rel_desc, new_rel_oid, reloptions);
}
/* --------------------------------
* AddNewRelationType -
*
* define a composite type corresponding to the new relation
* --------------------------------
*/
static Oid
AddNewRelationType(const char *typeName,
Oid typeNamespace,
Oid new_rel_oid,
char new_rel_kind,
Oid new_array_type)
{
return
TypeCreate(InvalidOid, /* no predetermined OID */
typeName, /* type name */
typeNamespace, /* type namespace */
new_rel_oid, /* relation oid */
new_rel_kind, /* relation kind */
-1, /* internal size (varlena) */
TYPTYPE_COMPOSITE, /* type-type (composite) */
DEFAULT_TYPDELIM, /* default array delimiter */
F_RECORD_IN, /* input procedure */
F_RECORD_OUT, /* output procedure */
F_RECORD_RECV, /* receive procedure */
F_RECORD_SEND, /* send procedure */
InvalidOid, /* typmodin procedure - none */
InvalidOid, /* typmodout procedure - none */
InvalidOid, /* analyze procedure - default */
InvalidOid, /* array element type - irrelevant */
false, /* this is not an array type */
new_array_type, /* array type if any */
InvalidOid, /* domain base type - irrelevant */
NULL, /* default value - none */
NULL, /* default binary representation */
false, /* passed by reference */
'd', /* alignment - must be the largest! */
'x', /* fully TOASTable */
-1, /* typmod */
0, /* array dimensions for typBaseType */
false); /* Type NOT NULL */
}
/* --------------------------------
* heap_create_with_catalog
*
* creates a new cataloged relation. see comments above.
* --------------------------------
*/
Oid
heap_create_with_catalog(const char *relname,
Oid relnamespace,
Oid reltablespace,
Oid relid,
Oid ownerid,
TupleDesc tupdesc,
char relkind,
bool shared_relation,
bool oidislocal,
int oidinhcount,
OnCommitAction oncommit,
Datum reloptions,
bool allow_system_table_mods)
{
Relation pg_class_desc;
Relation new_rel_desc;
Oid new_type_oid;
Oid new_array_oid = InvalidOid;
pg_class_desc = heap_open(RelationRelationId, RowExclusiveLock);
/*
* sanity checks
*/
Assert(IsNormalProcessingMode() || IsBootstrapProcessingMode());
CheckAttributeNamesTypes(tupdesc, relkind);
if (get_relname_relid(relname, relnamespace))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists", relname)));
/*
* Allocate an OID for the relation, unless we were told what to use.
*
* The OID will be the relfilenode as well, so make sure it doesn't
* collide with either pg_class OIDs or existing physical files.
*/
if (!OidIsValid(relid))
relid = GetNewRelFileNode(reltablespace, shared_relation,
pg_class_desc);
/*
* Create the relcache entry (mostly dummy at this point) and the physical
* disk file. (If we fail further down, it's the smgr's responsibility to
* remove the disk file again.)
*/
new_rel_desc = heap_create(relname,
relnamespace,
reltablespace,
relid,
tupdesc,
relkind,
shared_relation,
allow_system_table_mods);
Assert(relid == RelationGetRelid(new_rel_desc));
/*
* Decide whether to create an array type over the relation's rowtype.
* We do not create any array types for system catalogs (ie, those made
* during initdb). We create array types for regular relations, views,
* and composite types ... but not, eg, for toast tables or sequences.
*/
if (IsUnderPostmaster && (relkind == RELKIND_RELATION ||
relkind == RELKIND_VIEW ||
relkind == RELKIND_COMPOSITE_TYPE))
{
/* OK, so pre-assign a type OID for the array type */
Relation pg_type = heap_open(TypeRelationId, AccessShareLock);
new_array_oid = GetNewOid(pg_type);
heap_close(pg_type, AccessShareLock);
}
/*
* Since defining a relation also defines a complex type, we add a new
* system type corresponding to the new relation.
*
* NOTE: we could get a unique-index failure here, in case the same name
* has already been used for a type.
*/
new_type_oid = AddNewRelationType(relname,
relnamespace,
relid,
relkind,
new_array_oid);
/*
* Now make the array type if wanted.
*/
if (OidIsValid(new_array_oid))
{
char *relarrayname;
relarrayname = makeArrayTypeName(relname, relnamespace);
TypeCreate(new_array_oid, /* force the type's OID to this */
relarrayname, /* Array type name */
relnamespace, /* Same namespace as parent */
InvalidOid, /* Not composite, no relationOid */
0, /* relkind, also N/A here */
-1, /* Internal size (varlena) */
TYPTYPE_BASE, /* Not composite - typelem is */
DEFAULT_TYPDELIM, /* default array delimiter */
F_ARRAY_IN, /* array input proc */
F_ARRAY_OUT, /* array output proc */
F_ARRAY_RECV, /* array recv (bin) proc */
F_ARRAY_SEND, /* array send (bin) proc */
InvalidOid, /* typmodin procedure - none */
InvalidOid, /* typmodout procedure - none */
InvalidOid, /* analyze procedure - default */
new_type_oid, /* array element type - the rowtype */
true, /* yes, this is an array type */
InvalidOid, /* this has no array type */
InvalidOid, /* domain base type - irrelevant */
NULL, /* default value - none */
NULL, /* default binary representation */
false, /* passed by reference */
'd', /* alignment - must be the largest! */
'x', /* fully TOASTable */
-1, /* typmod */
0, /* array dimensions for typBaseType */
false); /* Type NOT NULL */
pfree(relarrayname);
}
/*
* now create an entry in pg_class for the relation.
*
* NOTE: we could get a unique-index failure here, in case someone else is
* creating the same relation name in parallel but hadn't committed yet
* when we checked for a duplicate name above.
*/
AddNewRelationTuple(pg_class_desc,
new_rel_desc,
relid,
new_type_oid,
ownerid,
relkind,
reloptions);
/*
* now add tuples to pg_attribute for the attributes in our new relation.
*/
AddNewAttributeTuples(relid, new_rel_desc->rd_att, relkind,
oidislocal, oidinhcount);
/*
* Make a dependency link to force the relation to be deleted if its
* namespace is. Also make a dependency link to its owner.
*
* For composite types, these dependencies are tracked for the pg_type
* entry, so we needn't record them here. Also, skip this in bootstrap
* mode, since we don't make dependencies while bootstrapping.
*/
if (relkind != RELKIND_COMPOSITE_TYPE &&
!IsBootstrapProcessingMode())
{
ObjectAddress myself,
referenced;
myself.classId = RelationRelationId;
myself.objectId = relid;
myself.objectSubId = 0;
referenced.classId = NamespaceRelationId;
referenced.objectId = relnamespace;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
recordDependencyOnOwner(RelationRelationId, relid, ownerid);
}
/*
* store constraints and defaults passed in the tupdesc, if any.
*
* NB: this may do a CommandCounterIncrement and rebuild the relcache
* entry, so the relation must be valid and self-consistent at this point.
* In particular, there are not yet constraints and defaults anywhere.
*/
StoreConstraints(new_rel_desc, tupdesc);
/*
* If there's a special on-commit action, remember it
*/
if (oncommit != ONCOMMIT_NOOP)
register_on_commit_action(relid, oncommit);
/*
* ok, the relation has been cataloged, so close our relations and return
* the OID of the newly created relation.
*/
heap_close(new_rel_desc, NoLock); /* do not unlock till end of xact */
heap_close(pg_class_desc, RowExclusiveLock);
return relid;
}
/*
* RelationRemoveInheritance
*
* Formerly, this routine checked for child relations and aborted the
* deletion if any were found. Now we rely on the dependency mechanism
* to check for or delete child relations. By the time we get here,
* there are no children and we need only remove any pg_inherits rows
* linking this relation to its parent(s).
*/
static void
RelationRemoveInheritance(Oid relid)
{
Relation catalogRelation;
SysScanDesc scan;
ScanKeyData key;
HeapTuple tuple;
catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
ScanKeyInit(&key,
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
simple_heap_delete(catalogRelation, &tuple->t_self);
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
}
/*
* DeleteRelationTuple
*
* Remove pg_class row for the given relid.
*
* Note: this is shared by relation deletion and index deletion. It's
* not intended for use anyplace else.
*/
void
DeleteRelationTuple(Oid relid)
{
Relation pg_class_desc;
HeapTuple tup;
/* Grab an appropriate lock on the pg_class relation */
pg_class_desc = heap_open(RelationRelationId, RowExclusiveLock);
tup = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for relation %u", relid);
/* delete the relation tuple from pg_class, and finish up */
simple_heap_delete(pg_class_desc, &tup->t_self);
ReleaseSysCache(tup);
heap_close(pg_class_desc, RowExclusiveLock);
}
/*
* DeleteAttributeTuples
*
* Remove pg_attribute rows for the given relid.
*
* Note: this is shared by relation deletion and index deletion. It's
* not intended for use anyplace else.
*/
void
DeleteAttributeTuples(Oid relid)
{
Relation attrel;
SysScanDesc scan;
ScanKeyData key[1];
HeapTuple atttup;
/* Grab an appropriate lock on the pg_attribute relation */
attrel = heap_open(AttributeRelationId, RowExclusiveLock);
/* Use the index to scan only attributes of the target relation */
ScanKeyInit(&key[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
scan = systable_beginscan(attrel, AttributeRelidNumIndexId, true,
SnapshotNow, 1, key);
/* Delete all the matching tuples */
while ((atttup = systable_getnext(scan)) != NULL)
simple_heap_delete(attrel, &atttup->t_self);
/* Clean up after the scan */
systable_endscan(scan);
heap_close(attrel, RowExclusiveLock);
}
/*
* RemoveAttributeById
*
* This is the guts of ALTER TABLE DROP COLUMN: actually mark the attribute
* deleted in pg_attribute. We also remove pg_statistic entries for it.
* (Everything else needed, such as getting rid of any pg_attrdef entry,
* is handled by dependency.c.)
*/
void
RemoveAttributeById(Oid relid, AttrNumber attnum)
{
Relation rel;
Relation attr_rel;
HeapTuple tuple;
Form_pg_attribute attStruct;
char newattname[NAMEDATALEN];
/*
* Grab an exclusive lock on the target table, which we will NOT release
* until end of transaction. (In the simple case where we are directly
* dropping this column, AlterTableDropColumn already did this ... but
* when cascading from a drop of some other object, we may not have any
* lock.)
*/
rel = relation_open(relid, AccessExclusiveLock);
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(relid),
Int16GetDatum(attnum),
0, 0);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, relid);
attStruct = (Form_pg_attribute) GETSTRUCT(tuple);
if (attnum < 0)
{
/* System attribute (probably OID) ... just delete the row */
simple_heap_delete(attr_rel, &tuple->t_self);
}
else
{
/* Dropping user attributes is lots harder */
/* Mark the attribute as dropped */
attStruct->attisdropped = true;
/*
* Set the type OID to invalid. A dropped attribute's type link
* cannot be relied on (once the attribute is dropped, the type might
* be too). Fortunately we do not need the type row --- the only
* really essential information is the type's typlen and typalign,
* which are preserved in the attribute's attlen and attalign. We set
* atttypid to zero here as a means of catching code that incorrectly
* expects it to be valid.
*/
attStruct->atttypid = InvalidOid;
/* Remove any NOT NULL constraint the column may have */
attStruct->attnotnull = false;
/* We don't want to keep stats for it anymore */
attStruct->attstattarget = 0;
/*
* Change the column name to something that isn't likely to conflict
*/
snprintf(newattname, sizeof(newattname),
"........pg.dropped.%d........", attnum);
namestrcpy(&(attStruct->attname), newattname);
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
}
/*
* Because updating the pg_attribute row will trigger a relcache flush for
* the target relation, we need not do anything else to notify other
* backends of the change.
*/
heap_close(attr_rel, RowExclusiveLock);
if (attnum > 0)
RemoveStatistics(relid, attnum);
relation_close(rel, NoLock);
}
/*
* RemoveAttrDefault
*
* If the specified relation/attribute has a default, remove it.
* (If no default, raise error if complain is true, else return quietly.)
*/
void
RemoveAttrDefault(Oid relid, AttrNumber attnum,
DropBehavior behavior, bool complain)
{
Relation attrdef_rel;
ScanKeyData scankeys[2];
SysScanDesc scan;
HeapTuple tuple;
bool found = false;
attrdef_rel = heap_open(AttrDefaultRelationId, RowExclusiveLock);
ScanKeyInit(&scankeys[0],
Anum_pg_attrdef_adrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
ScanKeyInit(&scankeys[1],
Anum_pg_attrdef_adnum,
BTEqualStrategyNumber, F_INT2EQ,
Int16GetDatum(attnum));
scan = systable_beginscan(attrdef_rel, AttrDefaultIndexId, true,
SnapshotNow, 2, scankeys);
/* There should be at most one matching tuple, but we loop anyway */
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
{
ObjectAddress object;
object.classId = AttrDefaultRelationId;
object.objectId = HeapTupleGetOid(tuple);
object.objectSubId = 0;
performDeletion(&object, behavior);
found = true;
}
systable_endscan(scan);
heap_close(attrdef_rel, RowExclusiveLock);
if (complain && !found)
elog(ERROR, "could not find attrdef tuple for relation %u attnum %d",
relid, attnum);
}
/*
* RemoveAttrDefaultById
*
* Remove a pg_attrdef entry specified by OID. This is the guts of
* attribute-default removal. Note it should be called via performDeletion,
* not directly.
*/
void
RemoveAttrDefaultById(Oid attrdefId)
{
Relation attrdef_rel;
Relation attr_rel;
Relation myrel;
ScanKeyData scankeys[1];
SysScanDesc scan;
HeapTuple tuple;
Oid myrelid;
AttrNumber myattnum;
/* Grab an appropriate lock on the pg_attrdef relation */
attrdef_rel = heap_open(AttrDefaultRelationId, RowExclusiveLock);
/* Find the pg_attrdef tuple */
ScanKeyInit(&scankeys[0],
ObjectIdAttributeNumber,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(attrdefId));
scan = systable_beginscan(attrdef_rel, AttrDefaultOidIndexId, true,
SnapshotNow, 1, scankeys);
tuple = systable_getnext(scan);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "could not find tuple for attrdef %u", attrdefId);
myrelid = ((Form_pg_attrdef) GETSTRUCT(tuple))->adrelid;
myattnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
/* Get an exclusive lock on the relation owning the attribute */
myrel = relation_open(myrelid, AccessExclusiveLock);
/* Now we can delete the pg_attrdef row */
simple_heap_delete(attrdef_rel, &tuple->t_self);
systable_endscan(scan);
heap_close(attrdef_rel, RowExclusiveLock);
/* Fix the pg_attribute row */
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(myrelid),
Int16GetDatum(myattnum),
0, 0);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
myattnum, myrelid);
((Form_pg_attribute) GETSTRUCT(tuple))->atthasdef = false;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/*
* Our update of the pg_attribute row will force a relcache rebuild, so
* there's nothing else to do here.
*/
heap_close(attr_rel, RowExclusiveLock);
/* Keep lock on attribute's rel until end of xact */
relation_close(myrel, NoLock);
}
/*
* heap_drop_with_catalog - removes specified relation from catalogs
*
* Note that this routine is not responsible for dropping objects that are
* linked to the pg_class entry via dependencies (for example, indexes and
* constraints). Those are deleted by the dependency-tracing logic in
* dependency.c before control gets here. In general, therefore, this routine
* should never be called directly; go through performDeletion() instead.
*/
void
heap_drop_with_catalog(Oid relid)
{
Relation rel;
/*
* Open and lock the relation.
*/
rel = relation_open(relid, AccessExclusiveLock);
/*
* Schedule unlinking of the relation's physical file at commit.
*/
if (rel->rd_rel->relkind != RELKIND_VIEW &&
rel->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
{
RelationOpenSmgr(rel);
smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
}
/*
* Close relcache entry, but *keep* AccessExclusiveLock on the relation
* until transaction commit. This ensures no one else will try to do
* something with the doomed relation.
*/
relation_close(rel, NoLock);
/*
* Forget any ON COMMIT action for the rel
*/
remove_on_commit_action(relid);
/*
* Flush the relation from the relcache. We want to do this before
* starting to remove catalog entries, just to be certain that no relcache
* entry rebuild will happen partway through. (That should not really
* matter, since we don't do CommandCounterIncrement here, but let's be
* safe.)
*/
RelationForgetRelation(relid);
/*
* remove inheritance information
*/
RelationRemoveInheritance(relid);
/*
* delete statistics
*/
RemoveStatistics(relid, 0);
/*
* delete attribute tuples
*/
DeleteAttributeTuples(relid);
/*
* delete relation tuple
*/
DeleteRelationTuple(relid);
}
/*
* Store a default expression for column attnum of relation rel.
* The expression must be presented as a nodeToString() string.
*/
void
StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
{
Node *expr;
char *adsrc;
Relation adrel;
HeapTuple tuple;
Datum values[4];
static char nulls[4] = {' ', ' ', ' ', ' '};
Relation attrrel;
HeapTuple atttup;
Form_pg_attribute attStruct;
Oid attrdefOid;
ObjectAddress colobject,
defobject;
/*
* Need to construct source equivalent of given node-string.
*/
expr = stringToNode(adbin);
/*
* deparse it
*/
adsrc = deparse_expression(expr,
deparse_context_for(RelationGetRelationName(rel),
RelationGetRelid(rel)),
false, false);
/*
* Make the pg_attrdef entry.
*/
values[Anum_pg_attrdef_adrelid - 1] = RelationGetRelid(rel);
values[Anum_pg_attrdef_adnum - 1] = attnum;
values[Anum_pg_attrdef_adbin - 1] = DirectFunctionCall1(textin,
CStringGetDatum(adbin));
values[Anum_pg_attrdef_adsrc - 1] = DirectFunctionCall1(textin,
CStringGetDatum(adsrc));
adrel = heap_open(AttrDefaultRelationId, RowExclusiveLock);
tuple = heap_formtuple(adrel->rd_att, values, nulls);
attrdefOid = simple_heap_insert(adrel, tuple);
CatalogUpdateIndexes(adrel, tuple);
defobject.classId = AttrDefaultRelationId;
defobject.objectId = attrdefOid;
defobject.objectSubId = 0;
heap_close(adrel, RowExclusiveLock);
/* now can free some of the stuff allocated above */
pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1]));
pfree(DatumGetPointer(values[Anum_pg_attrdef_adsrc - 1]));
heap_freetuple(tuple);
pfree(adsrc);
/*
* Update the pg_attribute entry for the column to show that a default
* exists.
*/
attrrel = heap_open(AttributeRelationId, RowExclusiveLock);
atttup = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(RelationGetRelid(rel)),
Int16GetDatum(attnum),
0, 0);
if (!HeapTupleIsValid(atttup))
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
attnum, RelationGetRelid(rel));
attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
if (!attStruct->atthasdef)
{
attStruct->atthasdef = true;
simple_heap_update(attrrel, &atttup->t_self, atttup);
/* keep catalog indexes current */
CatalogUpdateIndexes(attrrel, atttup);
}
heap_close(attrrel, RowExclusiveLock);
heap_freetuple(atttup);
/*
* Make a dependency so that the pg_attrdef entry goes away if the column
* (or whole table) is deleted.
*/
colobject.classId = RelationRelationId;
colobject.objectId = RelationGetRelid(rel);
colobject.objectSubId = attnum;
recordDependencyOn(&defobject, &colobject, DEPENDENCY_AUTO);
/*
* Record dependencies on objects used in the expression, too.
*/
recordDependencyOnExpr(&defobject, expr, NIL, DEPENDENCY_NORMAL);
}
/*
* Store a check-constraint expression for the given relation.
* The expression must be presented as a nodeToString() string.
*
* Caller is responsible for updating the count of constraints
* in the pg_class entry for the relation.
*/
static void
StoreRelCheck(Relation rel, char *ccname, char *ccbin)
{
Node *expr;
char *ccsrc;
List *varList;
int keycount;
int16 *attNos;
/*
* Convert condition to an expression tree.
*/
expr = stringToNode(ccbin);
/*
* deparse it
*/
ccsrc = deparse_expression(expr,
deparse_context_for(RelationGetRelationName(rel),
RelationGetRelid(rel)),
false, false);
/*
* Find columns of rel that are used in ccbin
*
* NB: pull_var_clause is okay here only because we don't allow subselects
* in check constraints; it would fail to examine the contents of
* subselects.
*/
varList = pull_var_clause(expr, false);
keycount = list_length(varList);
if (keycount > 0)
{
ListCell *vl;
int i = 0;
attNos = (int16 *) palloc(keycount * sizeof(int16));
foreach(vl, varList)
{
Var *var = (Var *) lfirst(vl);
int j;
for (j = 0; j < i; j++)
if (attNos[j] == var->varattno)
break;
if (j == i)
attNos[i++] = var->varattno;
}
keycount = i;
}
else
attNos = NULL;
/*
* Create the Check Constraint
*/
CreateConstraintEntry(ccname, /* Constraint Name */
RelationGetNamespace(rel), /* namespace */
CONSTRAINT_CHECK, /* Constraint Type */
false, /* Is Deferrable */
false, /* Is Deferred */
RelationGetRelid(rel), /* relation */
attNos, /* attrs in the constraint */
keycount, /* # attrs in the constraint */
InvalidOid, /* not a domain constraint */
InvalidOid, /* Foreign key fields */
NULL,
NULL,
NULL,
NULL,
0,
' ',
' ',
' ',
InvalidOid, /* no associated index */
expr, /* Tree form check constraint */
ccbin, /* Binary form check constraint */
ccsrc); /* Source form check constraint */
pfree(ccsrc);
}
/*
* Store defaults and constraints passed in via the tuple constraint struct.
*
* NOTE: only pre-cooked expressions will be passed this way, which is to
* say expressions inherited from an existing relation. Newly parsed
* expressions can be added later, by direct calls to StoreAttrDefault
* and StoreRelCheck (see AddRelationRawConstraints()).
*/
static void
StoreConstraints(Relation rel, TupleDesc tupdesc)
{
TupleConstr *constr = tupdesc->constr;
int i;
if (!constr)
return; /* nothing to do */
/*
* Deparsing of constraint expressions will fail unless the just-created
* pg_attribute tuples for this relation are made visible. So, bump the
* command counter. CAUTION: this will cause a relcache entry rebuild.
*/
CommandCounterIncrement();
for (i = 0; i < constr->num_defval; i++)
StoreAttrDefault(rel, constr->defval[i].adnum,
constr->defval[i].adbin);
for (i = 0; i < constr->num_check; i++)
StoreRelCheck(rel, constr->check[i].ccname,
constr->check[i].ccbin);
if (constr->num_check > 0)
SetRelationNumChecks(rel, constr->num_check);
}
/*
* AddRelationRawConstraints
*
* Add raw (not-yet-transformed) column default expressions and/or constraint
* check expressions to an existing relation. This is defined to do both
* for efficiency in DefineRelation, but of course you can do just one or
* the other by passing empty lists.
*
* rel: relation to be modified
* rawColDefaults: list of RawColumnDefault structures
* rawConstraints: list of Constraint nodes
*
* All entries in rawColDefaults will be processed. Entries in rawConstraints
* will be processed only if they are CONSTR_CHECK type and contain a "raw"
* expression.
*
* Returns a list of CookedConstraint nodes that shows the cooked form of
* the default and constraint expressions added to the relation.
*
* NB: caller should have opened rel with AccessExclusiveLock, and should
* hold that lock till end of transaction. Also, we assume the caller has
* done a CommandCounterIncrement if necessary to make the relation's catalog
* tuples visible.
*/
List *
AddRelationRawConstraints(Relation rel,
List *rawColDefaults,
List *rawConstraints)
{
List *cookedConstraints = NIL;
TupleDesc tupleDesc;
TupleConstr *oldconstr;
int numoldchecks;
ParseState *pstate;
RangeTblEntry *rte;
int numchecks;
List *checknames;
ListCell *cell;
Node *expr;
CookedConstraint *cooked;
/*
* Get info about existing constraints.
*/
tupleDesc = RelationGetDescr(rel);
oldconstr = tupleDesc->constr;
if (oldconstr)
numoldchecks = oldconstr->num_check;
else
numoldchecks = 0;
/*
* Create a dummy ParseState and insert the target relation as its sole
* rangetable entry. We need a ParseState for transformExpr.
*/
pstate = make_parsestate(NULL);
rte = addRangeTableEntryForRelation(pstate,
rel,
NULL,
false,
true);
addRTEtoQuery(pstate, rte, true, true, true);
/*
* Process column default expressions.
*/
foreach(cell, rawColDefaults)
{
RawColumnDefault *colDef = (RawColumnDefault *) lfirst(cell);
Form_pg_attribute atp = rel->rd_att->attrs[colDef->attnum - 1];
expr = cookDefault(pstate, colDef->raw_default,
atp->atttypid, atp->atttypmod,
NameStr(atp->attname));
StoreAttrDefault(rel, colDef->attnum, nodeToString(expr));
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_DEFAULT;
cooked->name = NULL;
cooked->attnum = colDef->attnum;
cooked->expr = expr;
cookedConstraints = lappend(cookedConstraints, cooked);
}
/*
* Process constraint expressions.
*/
numchecks = numoldchecks;
checknames = NIL;
foreach(cell, rawConstraints)
{
Constraint *cdef = (Constraint *) lfirst(cell);
char *ccname;
if (cdef->contype != CONSTR_CHECK || cdef->raw_expr == NULL)
continue;
Assert(cdef->cooked_expr == NULL);
/*
* Transform raw parsetree to executable expression.
*/
expr = transformExpr(pstate, cdef->raw_expr);
/*
* Make sure it yields a boolean result.
*/
expr = coerce_to_boolean(pstate, expr, "CHECK");
/*
* Make sure no outside relations are referred to.
*/
if (list_length(pstate->p_rtable) != 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("only table \"%s\" can be referenced in check constraint",
RelationGetRelationName(rel))));
/*
* No subplans or aggregates, either...
*/
if (pstate->p_hasSubLinks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in check constraint")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in check constraint")));
/*
* Check name uniqueness, or generate a name if none was given.
*/
if (cdef->name != NULL)
{
ListCell *cell2;
ccname = cdef->name;
/* Check against pre-existing constraints */
if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
RelationGetRelid(rel),
RelationGetNamespace(rel),
ccname))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("constraint \"%s\" for relation \"%s\" already exists",
ccname, RelationGetRelationName(rel))));
/* Check against other new constraints */
/* Needed because we don't do CommandCounterIncrement in loop */
foreach(cell2, checknames)
{
if (strcmp((char *) lfirst(cell2), ccname) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("check constraint \"%s\" already exists",
ccname)));
}
}
else
{
/*
* When generating a name, we want to create "tab_col_check" for a
* column constraint and "tab_check" for a table constraint. We
* no longer have any info about the syntactic positioning of the
* constraint phrase, so we approximate this by seeing whether the
* expression references more than one column. (If the user
* played by the rules, the result is the same...)
*
* Note: pull_var_clause() doesn't descend into sublinks, but we
* eliminated those above; and anyway this only needs to be an
* approximate answer.
*/
List *vars;
char *colname;
vars = pull_var_clause(expr, false);
/* eliminate duplicates */
vars = list_union(NIL, vars);
if (list_length(vars) == 1)
colname = get_attname(RelationGetRelid(rel),
((Var *) linitial(vars))->varattno);
else
colname = NULL;
ccname = ChooseConstraintName(RelationGetRelationName(rel),
colname,
"check",
RelationGetNamespace(rel),
checknames);
}
/* save name for future checks */
checknames = lappend(checknames, ccname);
/*
* OK, store it.
*/
StoreRelCheck(rel, ccname, nodeToString(expr));
numchecks++;
cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
cooked->contype = CONSTR_CHECK;
cooked->name = ccname;
cooked->attnum = 0;
cooked->expr = expr;
cookedConstraints = lappend(cookedConstraints, cooked);
}
/*
* Update the count of constraints in the relation's pg_class tuple. We do
* this even if there was no change, in order to ensure that an SI update
* message is sent out for the pg_class tuple, which will force other
* backends to rebuild their relcache entries for the rel. (This is
* critical if we added defaults but not constraints.)
*/
SetRelationNumChecks(rel, numchecks);
return cookedConstraints;
}
/*
* Update the count of constraints in the relation's pg_class tuple.
*
* Caller had better hold exclusive lock on the relation.
*
* An important side effect is that a SI update message will be sent out for
* the pg_class tuple, which will force other backends to rebuild their
* relcache entries for the rel. Also, this backend will rebuild its
* own relcache entry at the next CommandCounterIncrement.
*/
static void
SetRelationNumChecks(Relation rel, int numchecks)
{
Relation relrel;
HeapTuple reltup;
Form_pg_class relStruct;
relrel = heap_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)),
0, 0, 0);
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
relStruct = (Form_pg_class) GETSTRUCT(reltup);
if (relStruct->relchecks != numchecks)
{
relStruct->relchecks = numchecks;
simple_heap_update(relrel, &reltup->t_self, reltup);
/* keep catalog indexes current */
CatalogUpdateIndexes(relrel, reltup);
}
else
{
/* Skip the disk update, but force relcache inval anyway */
CacheInvalidateRelcache(rel);
}
heap_freetuple(reltup);
heap_close(relrel, RowExclusiveLock);
}
/*
* Take a raw default and convert it to a cooked format ready for
* storage.
*
* Parse state should be set up to recognize any vars that might appear
* in the expression. (Even though we plan to reject vars, it's more
* user-friendly to give the correct error message than "unknown var".)
*
* If atttypid is not InvalidOid, coerce the expression to the specified
* type (and typmod atttypmod). attname is only needed in this case:
* it is used in the error message, if any.
*/
Node *
cookDefault(ParseState *pstate,
Node *raw_default,
Oid atttypid,
int32 atttypmod,
char *attname)
{
Node *expr;
Assert(raw_default != NULL);
/*
* Transform raw parsetree to executable expression.
*/
expr = transformExpr(pstate, raw_default);
/*
* Make sure default expr does not refer to any vars.
*/
if (contain_var_clause(expr))
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("cannot use column references in default expression")));
/*
* It can't return a set either.
*/
if (expression_returns_set(expr))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("default expression must not return a set")));
/*
* No subplans or aggregates, either...
*/
if (pstate->p_hasSubLinks)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot use subquery in default expression")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in default expression")));
/*
* Coerce the expression to the correct type and typmod, if given. This
* should match the parser's processing of non-defaulted expressions ---
* see transformAssignedExpr().
*/
if (OidIsValid(atttypid))
{
Oid type_id = exprType(expr);
expr = coerce_to_target_type(pstate, expr, type_id,
atttypid, atttypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST);
if (expr == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" is of type %s"
" but default expression is of type %s",
attname,
format_type_be(atttypid),
format_type_be(type_id)),
errhint("You will need to rewrite or cast the expression.")));
}
return expr;
}
/*
* Removes all constraints on a relation that match the given name.
*
* It is the responsibility of the calling function to acquire a suitable
* lock on the relation.
*
* Returns: The number of constraints removed.
*/
int
RemoveRelConstraints(Relation rel, const char *constrName,
DropBehavior behavior)
{
int ndeleted = 0;
Relation conrel;
SysScanDesc conscan;
ScanKeyData key[1];
HeapTuple contup;
/* Grab an appropriate lock on the pg_constraint relation */
conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
/* Use the index to scan only constraints of the target relation */
ScanKeyInit(&key[0],
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
SnapshotNow, 1, key);
/*
* Scan over the result set, removing any matching entries.
*/
while ((contup = systable_getnext(conscan)) != NULL)
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(contup);
if (strcmp(NameStr(con->conname), constrName) == 0)
{
ObjectAddress conobj;
conobj.classId = ConstraintRelationId;
conobj.objectId = HeapTupleGetOid(contup);
conobj.objectSubId = 0;
performDeletion(&conobj, behavior);
ndeleted++;
}
}
/* Clean up after the scan */
systable_endscan(conscan);
heap_close(conrel, RowExclusiveLock);
return ndeleted;
}
/*
* RemoveStatistics --- remove entries in pg_statistic for a rel or column
*
* If attnum is zero, remove all entries for rel; else remove only the one
* for that column.
*/
void
RemoveStatistics(Oid relid, AttrNumber attnum)
{
Relation pgstatistic;
SysScanDesc scan;
ScanKeyData key[2];
int nkeys;
HeapTuple tuple;
pgstatistic = heap_open(StatisticRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_statistic_starelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
if (attnum == 0)
nkeys = 1;
else
{
ScanKeyInit(&key[1],
Anum_pg_statistic_staattnum,
BTEqualStrategyNumber, F_INT2EQ,
Int16GetDatum(attnum));
nkeys = 2;
}
scan = systable_beginscan(pgstatistic, StatisticRelidAttnumIndexId, true,
SnapshotNow, nkeys, key);
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
simple_heap_delete(pgstatistic, &tuple->t_self);
systable_endscan(scan);
heap_close(pgstatistic, RowExclusiveLock);
}
/*
* RelationTruncateIndexes - truncate all indexes associated
* with the heap relation to zero tuples.
*
* The routine will truncate and then reconstruct the indexes on
* the specified relation. Caller must hold exclusive lock on rel.
*/
static void
RelationTruncateIndexes(Relation heapRelation)
{
ListCell *indlist;
/* Ask the relcache to produce a list of the indexes of the rel */
foreach(indlist, RelationGetIndexList(heapRelation))
{
Oid indexId = lfirst_oid(indlist);
Relation currentIndex;
IndexInfo *indexInfo;
/* Open the index relation; use exclusive lock, just to be sure */
currentIndex = index_open(indexId, AccessExclusiveLock);
/* Fetch info needed for index_build */
indexInfo = BuildIndexInfo(currentIndex);
/* Now truncate the actual file (and discard buffers) */
RelationTruncate(currentIndex, 0);
/* Initialize the index and rebuild */
/* Note: we do not need to re-establish pkey setting */
index_build(heapRelation, currentIndex, indexInfo, false);
/* We're done with this index */
index_close(currentIndex, NoLock);
}
}
/*
* heap_truncate
*
* This routine deletes all data within all the specified relations.
*
* This is not transaction-safe! There is another, transaction-safe
* implementation in commands/tablecmds.c. We now use this only for
* ON COMMIT truncation of temporary tables, where it doesn't matter.
*/
void
heap_truncate(List *relids)
{
List *relations = NIL;
ListCell *cell;
/* Open relations for processing, and grab exclusive access on each */
foreach(cell, relids)
{
Oid rid = lfirst_oid(cell);
Relation rel;
Oid toastrelid;
rel = heap_open(rid, AccessExclusiveLock);
relations = lappend(relations, rel);
/* If there is a toast table, add it to the list too */
toastrelid = rel->rd_rel->reltoastrelid;
if (OidIsValid(toastrelid))
{
rel = heap_open(toastrelid, AccessExclusiveLock);
relations = lappend(relations, rel);
}
}
/* Don't allow truncate on tables that are referenced by foreign keys */
heap_truncate_check_FKs(relations, true);
/* OK to do it */
foreach(cell, relations)
{
Relation rel = lfirst(cell);
/* Truncate the actual file (and discard buffers) */
RelationTruncate(rel, 0);
/* If this relation has indexes, truncate the indexes too */
RelationTruncateIndexes(rel);
/*
* Close the relation, but keep exclusive lock on it until commit.
*/
heap_close(rel, NoLock);
}
}
/*
* heap_truncate_check_FKs
* Check for foreign keys referencing a list of relations that
* are to be truncated, and raise error if there are any
*
* We disallow such FKs (except self-referential ones) since the whole point
* of TRUNCATE is to not scan the individual rows to be thrown away.
*
* This is split out so it can be shared by both implementations of truncate.
* Caller should already hold a suitable lock on the relations.
*
* tempTables is only used to select an appropriate error message.
*/
void
heap_truncate_check_FKs(List *relations, bool tempTables)
{
List *oids = NIL;
List *dependents;
ListCell *cell;
/*
* Build a list of OIDs of the interesting relations.
*
* If a relation has no triggers, then it can neither have FKs nor be
* referenced by a FK from another table, so we can ignore it.
*/
foreach(cell, relations)
{
Relation rel = lfirst(cell);
if (rel->rd_rel->reltriggers != 0)
oids = lappend_oid(oids, RelationGetRelid(rel));
}
/*
* Fast path: if no relation has triggers, none has FKs either.
*/
if (oids == NIL)
return;
/*
* Otherwise, must scan pg_constraint. We make one pass with all the
* relations considered; if this finds nothing, then all is well.
*/
dependents = heap_truncate_find_FKs(oids);
if (dependents == NIL)
return;
/*
* Otherwise we repeat the scan once per relation to identify a particular
* pair of relations to complain about. This is pretty slow, but
* performance shouldn't matter much in a failure path. The reason for
* doing things this way is to ensure that the message produced is not
* dependent on chance row locations within pg_constraint.
*/
foreach(cell, oids)
{
Oid relid = lfirst_oid(cell);
ListCell *cell2;
dependents = heap_truncate_find_FKs(list_make1_oid(relid));
foreach(cell2, dependents)
{
Oid relid2 = lfirst_oid(cell2);
if (!list_member_oid(oids, relid2))
{
char *relname = get_rel_name(relid);
char *relname2 = get_rel_name(relid2);
if (tempTables)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unsupported ON COMMIT and foreign key combination"),
errdetail("Table \"%s\" references \"%s\", but they do not have the same ON COMMIT setting.",
relname2, relname)));
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot truncate a table referenced in a foreign key constraint"),
errdetail("Table \"%s\" references \"%s\".",
relname2, relname),
errhint("Truncate table \"%s\" at the same time, "
"or use TRUNCATE ... CASCADE.",
relname2)));
}
}
}
}
/*
* heap_truncate_find_FKs
* Find relations having foreign keys referencing any of the given rels
*
* Input and result are both lists of relation OIDs. The result contains
* no duplicates, does *not* include any rels that were already in the input
* list, and is sorted in OID order. (The last property is enforced mainly
* to guarantee consistent behavior in the regression tests; we don't want
* behavior to change depending on chance locations of rows in pg_constraint.)
*
* Note: caller should already have appropriate lock on all rels mentioned
* in relationIds. Since adding or dropping an FK requires exclusive lock
* on both rels, this ensures that the answer will be stable.
*/
List *
heap_truncate_find_FKs(List *relationIds)
{
List *result = NIL;
Relation fkeyRel;
SysScanDesc fkeyScan;
HeapTuple tuple;
/*
* Must scan pg_constraint. Right now, it is a seqscan because there is
* no available index on confrelid.
*/
fkeyRel = heap_open(ConstraintRelationId, AccessShareLock);
fkeyScan = systable_beginscan(fkeyRel, InvalidOid, false,
SnapshotNow, 0, NULL);
while (HeapTupleIsValid(tuple = systable_getnext(fkeyScan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
/* Not a foreign key */
if (con->contype != CONSTRAINT_FOREIGN)
continue;
/* Not referencing one of our list of tables */
if (!list_member_oid(relationIds, con->confrelid))
continue;
/* Add referencer unless already in input or result list */
if (!list_member_oid(relationIds, con->conrelid))
result = insert_ordered_unique_oid(result, con->conrelid);
}
systable_endscan(fkeyScan);
heap_close(fkeyRel, AccessShareLock);
return result;
}
/*
* insert_ordered_unique_oid
* Insert a new Oid into a sorted list of Oids, preserving ordering,
* and eliminating duplicates
*
* Building the ordered list this way is O(N^2), but with a pretty small
* constant, so for the number of entries we expect it will probably be
* faster than trying to apply qsort(). It seems unlikely someone would be
* trying to truncate a table with thousands of dependent tables ...
*/
static List *
insert_ordered_unique_oid(List *list, Oid datum)
{
ListCell *prev;
/* Does the datum belong at the front? */
if (list == NIL || datum < linitial_oid(list))
return lcons_oid(datum, list);
/* Does it match the first entry? */
if (datum == linitial_oid(list))
return list; /* duplicate, so don't insert */
/* No, so find the entry it belongs after */
prev = list_head(list);
for (;;)
{
ListCell *curr = lnext(prev);
if (curr == NULL || datum < lfirst_oid(curr))
break; /* it belongs after 'prev', before 'curr' */
if (datum == lfirst_oid(curr))
return list; /* duplicate, so don't insert */
prev = curr;
}
/* Insert datum into list after 'prev' */
lappend_cell_oid(list, prev, datum);
return list;
}
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