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postgresql/src/backend/commands/tablecmds.c

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/*-------------------------------------------------------------------------
*
* tablecmds.c
* Commands for creating and altering table structures and settings
*
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.220 2007/05/11 17:57:12 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/reloptions.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/namespace.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_depend.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "catalog/toasting.h"
#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "commands/trigger.h"
#include "commands/typecmds.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/plancat.h"
#include "optimizer/prep.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_expr.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
#include "parser/parser.h"
#include "rewrite/rewriteDefine.h"
#include "rewrite/rewriteHandler.h"
#include "storage/smgr.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
/*
* ON COMMIT action list
*/
typedef struct OnCommitItem
{
Oid relid; /* relid of relation */
OnCommitAction oncommit; /* what to do at end of xact */
/*
* If this entry was created during the current transaction,
* creating_subid is the ID of the creating subxact; if created in a prior
* transaction, creating_subid is zero. If deleted during the current
* transaction, deleting_subid is the ID of the deleting subxact; if no
* deletion request is pending, deleting_subid is zero.
*/
SubTransactionId creating_subid;
SubTransactionId deleting_subid;
} OnCommitItem;
static List *on_commits = NIL;
/*
* State information for ALTER TABLE
*
* The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
* structs, one for each table modified by the operation (the named table
* plus any child tables that are affected). We save lists of subcommands
* to apply to this table (possibly modified by parse transformation steps);
* these lists will be executed in Phase 2. If a Phase 3 step is needed,
* necessary information is stored in the constraints and newvals lists.
*
* Phase 2 is divided into multiple passes; subcommands are executed in
* a pass determined by subcommand type.
*/
#define AT_PASS_DROP 0 /* DROP (all flavors) */
#define AT_PASS_ALTER_TYPE 1 /* ALTER COLUMN TYPE */
#define AT_PASS_OLD_INDEX 2 /* re-add existing indexes */
#define AT_PASS_OLD_CONSTR 3 /* re-add existing constraints */
#define AT_PASS_COL_ATTRS 4 /* set other column attributes */
/* We could support a RENAME COLUMN pass here, but not currently used */
#define AT_PASS_ADD_COL 5 /* ADD COLUMN */
#define AT_PASS_ADD_INDEX 6 /* ADD indexes */
#define AT_PASS_ADD_CONSTR 7 /* ADD constraints, defaults */
#define AT_PASS_MISC 8 /* other stuff */
#define AT_NUM_PASSES 9
typedef struct AlteredTableInfo
{
/* Information saved before any work commences: */
Oid relid; /* Relation to work on */
char relkind; /* Its relkind */
TupleDesc oldDesc; /* Pre-modification tuple descriptor */
/* Information saved by Phase 1 for Phase 2: */
List *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */
/* Information saved by Phases 1/2 for Phase 3: */
List *constraints; /* List of NewConstraint */
List *newvals; /* List of NewColumnValue */
bool new_notnull; /* T if we added new NOT NULL constraints */
Oid newTableSpace; /* new tablespace; 0 means no change */
/* Objects to rebuild after completing ALTER TYPE operations */
List *changedConstraintOids; /* OIDs of constraints to rebuild */
List *changedConstraintDefs; /* string definitions of same */
List *changedIndexOids; /* OIDs of indexes to rebuild */
List *changedIndexDefs; /* string definitions of same */
} AlteredTableInfo;
/* Struct describing one new constraint to check in Phase 3 scan */
/* Note: new NOT NULL constraints are handled elsewhere */
typedef struct NewConstraint
{
char *name; /* Constraint name, or NULL if none */
ConstrType contype; /* CHECK or FOREIGN */
Oid refrelid; /* PK rel, if FOREIGN */
Oid conid; /* OID of pg_constraint entry, if FOREIGN */
Node *qual; /* Check expr or FkConstraint struct */
List *qualstate; /* Execution state for CHECK */
} NewConstraint;
/*
* Struct describing one new column value that needs to be computed during
* Phase 3 copy (this could be either a new column with a non-null default, or
* a column that we're changing the type of). Columns without such an entry
* are just copied from the old table during ATRewriteTable. Note that the
* expr is an expression over *old* table values.
*/
typedef struct NewColumnValue
{
AttrNumber attnum; /* which column */
Expr *expr; /* expression to compute */
ExprState *exprstate; /* execution state */
} NewColumnValue;
static void truncate_check_rel(Relation rel);
static List *MergeAttributes(List *schema, List *supers, bool istemp,
List **supOids, List **supconstr, int *supOidCount);
static void MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel);
static void MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel);
static void add_nonduplicate_constraint(Constraint *cdef,
ConstrCheck *check, int *ncheck);
static bool change_varattnos_walker(Node *node, const AttrNumber *newattno);
static void StoreCatalogInheritance(Oid relationId, List *supers);
static void StoreCatalogInheritance1(Oid relationId, Oid parentOid,
int16 seqNumber, Relation inhRelation);
static int findAttrByName(const char *attributeName, List *schema);
static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
static void AlterIndexNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid);
static void AlterSeqNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid,
const char *newNspName);
static int transformColumnNameList(Oid relId, List *colList,
int16 *attnums, Oid *atttypids);
static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
List **attnamelist,
int16 *attnums, Oid *atttypids,
Oid *opclasses);
static Oid transformFkeyCheckAttrs(Relation pkrel,
int numattrs, int16 *attnums,
Oid *opclasses);
static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
Relation rel, Relation pkrel, Oid constraintOid);
static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
Oid constraintOid);
static void ATController(Relation rel, List *cmds, bool recurse);
static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing);
static void ATRewriteCatalogs(List **wqueue);
static void ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd);
static void ATRewriteTables(List **wqueue);
static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap);
static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
static void ATSimplePermissions(Relation rel, bool allowView);
static void ATSimplePermissionsRelationOrIndex(Relation rel);
static void ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse);
static void ATOneLevelRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd);
static void find_composite_type_dependencies(Oid typeOid,
const char *origTblName);
static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
AlterTableCmd *cmd);
static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
ColumnDef *colDef);
static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
static void ATExecDropNotNull(Relation rel, const char *colName);
static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
const char *colName);
static void ATExecColumnDefault(Relation rel, const char *colName,
Node *newDefault);
static void ATPrepSetStatistics(Relation rel, const char *colName,
Node *flagValue);
static void ATExecSetStatistics(Relation rel, const char *colName,
Node *newValue);
static void ATExecSetStorage(Relation rel, const char *colName,
Node *newValue);
static void ATExecDropColumn(Relation rel, const char *colName,
DropBehavior behavior,
bool recurse, bool recursing);
static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
IndexStmt *stmt, bool is_rebuild);
static void ATExecAddConstraint(AlteredTableInfo *tab, Relation rel,
Node *newConstraint);
static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
FkConstraint *fkconstraint);
static void ATPrepDropConstraint(List **wqueue, Relation rel,
bool recurse, AlterTableCmd *cmd);
static void ATExecDropConstraint(Relation rel, const char *constrName,
DropBehavior behavior, bool quiet);
static void ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd);
static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
const char *colName, TypeName *typename);
static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab);
static void ATPostAlterTypeParse(char *cmd, List **wqueue);
static void change_owner_recurse_to_sequences(Oid relationOid,
Oid newOwnerId);
static void ATExecClusterOn(Relation rel, const char *indexName);
static void ATExecDropCluster(Relation rel);
static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
char *tablespacename);
static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
static void ATExecSetRelOptions(Relation rel, List *defList, bool isReset);
static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
char fires_when, bool skip_system);
static void ATExecEnableDisableRule(Relation rel, char *rulename,
char fires_when);
static void ATExecAddInherit(Relation rel, RangeVar *parent);
static void ATExecDropInherit(Relation rel, RangeVar *parent);
static void copy_relation_data(Relation rel, SMgrRelation dst);
/* ----------------------------------------------------------------
* DefineRelation
* Creates a new relation.
*
* If successful, returns the OID of the new relation.
* ----------------------------------------------------------------
*/
Oid
DefineRelation(CreateStmt *stmt, char relkind)
{
char relname[NAMEDATALEN];
Oid namespaceId;
List *schema = stmt->tableElts;
Oid relationId;
Oid tablespaceId;
Relation rel;
TupleDesc descriptor;
List *inheritOids;
List *old_constraints;
bool localHasOids;
int parentOidCount;
List *rawDefaults;
Datum reloptions;
ListCell *listptr;
AttrNumber attnum;
/*
* Truncate relname to appropriate length (probably a waste of time, as
* parser should have done this already).
*/
StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
/*
* Check consistency of arguments
*/
if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("ON COMMIT can only be used on temporary tables")));
/*
* Look up the namespace in which we are supposed to create the relation.
* Check we have permission to create there. Skip check if bootstrapping,
* since permissions machinery may not be working yet.
*/
namespaceId = RangeVarGetCreationNamespace(stmt->relation);
if (!IsBootstrapProcessingMode())
{
AclResult aclresult;
aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
get_namespace_name(namespaceId));
}
/*
* Select tablespace to use. If not specified, use default_tablespace
* (which may in turn default to database's default).
*/
if (stmt->tablespacename)
{
tablespaceId = get_tablespace_oid(stmt->tablespacename);
if (!OidIsValid(tablespaceId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist",
stmt->tablespacename)));
}
else
{
tablespaceId = GetDefaultTablespace();
/* note InvalidOid is OK in this case */
}
/*
* Parse and validate reloptions, if any.
*/
reloptions = transformRelOptions((Datum) 0, stmt->options, true, false);
(void) heap_reloptions(relkind, reloptions, true);
/* Check permissions except when using database's default */
if (OidIsValid(tablespaceId))
{
AclResult aclresult;
aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
get_tablespace_name(tablespaceId));
}
/*
* Look up inheritance ancestors and generate relation schema, including
* inherited attributes.
*/
schema = MergeAttributes(schema, stmt->inhRelations,
stmt->relation->istemp,
&inheritOids, &old_constraints, &parentOidCount);
/*
* Create a relation descriptor from the relation schema and create the
* relation. Note that in this stage only inherited (pre-cooked) defaults
* and constraints will be included into the new relation.
* (BuildDescForRelation takes care of the inherited defaults, but we have
* to copy inherited constraints here.)
*/
descriptor = BuildDescForRelation(schema);
localHasOids = interpretOidsOption(stmt->options);
descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
if (old_constraints || stmt->constraints)
{
ConstrCheck *check;
int ncheck = 0;
/* make array that's certainly big enough */
check = (ConstrCheck *)
palloc((list_length(old_constraints) +
list_length(stmt->constraints)) * sizeof(ConstrCheck));
/* deal with constraints from MergeAttributes */
foreach(listptr, old_constraints)
{
Constraint *cdef = (Constraint *) lfirst(listptr);
if (cdef->contype == CONSTR_CHECK)
add_nonduplicate_constraint(cdef, check, &ncheck);
}
/*
* analyze.c might have passed some precooked constraints too,
* due to LIKE tab INCLUDING CONSTRAINTS
*/
foreach(listptr, stmt->constraints)
{
Constraint *cdef = (Constraint *) lfirst(listptr);
if (cdef->contype == CONSTR_CHECK && cdef->cooked_expr != NULL)
add_nonduplicate_constraint(cdef, check, &ncheck);
}
/* if we found any, insert 'em into the descriptor */
if (ncheck > 0)
{
if (descriptor->constr == NULL)
{
descriptor->constr = (TupleConstr *) palloc(sizeof(TupleConstr));
descriptor->constr->defval = NULL;
descriptor->constr->num_defval = 0;
descriptor->constr->has_not_null = false;
}
descriptor->constr->num_check = ncheck;
descriptor->constr->check = check;
}
}
relationId = heap_create_with_catalog(relname,
namespaceId,
tablespaceId,
InvalidOid,
GetUserId(),
descriptor,
relkind,
false,
localHasOids,
parentOidCount,
stmt->oncommit,
reloptions,
allowSystemTableMods);
StoreCatalogInheritance(relationId, inheritOids);
/*
* We must bump the command counter to make the newly-created relation
* tuple visible for opening.
*/
CommandCounterIncrement();
/*
* Open the new relation and acquire exclusive lock on it. This isn't
* really necessary for locking out other backends (since they can't see
* the new rel anyway until we commit), but it keeps the lock manager from
* complaining about deadlock risks.
*/
rel = relation_open(relationId, AccessExclusiveLock);
/*
* Now add any newly specified column default values and CHECK constraints
* to the new relation. These are passed to us in the form of raw
* parsetrees; we need to transform them to executable expression trees
* before they can be added. The most convenient way to do that is to
* apply the parser's transformExpr routine, but transformExpr doesn't
* work unless we have a pre-existing relation. So, the transformation has
* to be postponed to this final step of CREATE TABLE.
*
* First, scan schema to find new column defaults.
*/
rawDefaults = NIL;
attnum = 0;
foreach(listptr, schema)
{
ColumnDef *colDef = lfirst(listptr);
attnum++;
if (colDef->raw_default != NULL)
{
RawColumnDefault *rawEnt;
Assert(colDef->cooked_default == NULL);
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = colDef->raw_default;
rawDefaults = lappend(rawDefaults, rawEnt);
}
}
/*
* Parse and add the defaults/constraints, if any.
*/
if (rawDefaults || stmt->constraints)
AddRelationRawConstraints(rel, rawDefaults, stmt->constraints);
/*
* Clean up. We keep lock on new relation (although it shouldn't be
* visible to anyone else anyway, until commit).
*/
relation_close(rel, NoLock);
return relationId;
}
/*
* RemoveRelation
* Deletes a relation.
*/
void
RemoveRelation(const RangeVar *relation, DropBehavior behavior)
{
Oid relOid;
ObjectAddress object;
relOid = RangeVarGetRelid(relation, false);
object.classId = RelationRelationId;
object.objectId = relOid;
object.objectSubId = 0;
performDeletion(&object, behavior);
}
/*
* ExecuteTruncate
* Executes a TRUNCATE command.
*
* This is a multi-relation truncate. We first open and grab exclusive
* lock on all relations involved, checking permissions and otherwise
* verifying that the relation is OK for truncation. In CASCADE mode,
* relations having FK references to the targeted relations are automatically
* added to the group; in RESTRICT mode, we check that all FK references are
* internal to the group that's being truncated. Finally all the relations
* are truncated and reindexed.
*/
void
ExecuteTruncate(TruncateStmt *stmt)
{
List *rels = NIL;
List *relids = NIL;
ListCell *cell;
/*
* Open, exclusive-lock, and check all the explicitly-specified relations
*/
foreach(cell, stmt->relations)
{
RangeVar *rv = lfirst(cell);
Relation rel;
rel = heap_openrv(rv, AccessExclusiveLock);
truncate_check_rel(rel);
rels = lappend(rels, rel);
relids = lappend_oid(relids, RelationGetRelid(rel));
}
/*
* In CASCADE mode, suck in all referencing relations as well. This
* requires multiple iterations to find indirectly-dependent relations. At
* each phase, we need to exclusive-lock new rels before looking for their
* dependencies, else we might miss something. Also, we check each rel as
* soon as we open it, to avoid a faux pas such as holding lock for a long
* time on a rel we have no permissions for.
*/
if (stmt->behavior == DROP_CASCADE)
{
for (;;)
{
List *newrelids;
newrelids = heap_truncate_find_FKs(relids);
if (newrelids == NIL)
break; /* nothing else to add */
foreach(cell, newrelids)
{
Oid relid = lfirst_oid(cell);
Relation rel;
rel = heap_open(relid, AccessExclusiveLock);
ereport(NOTICE,
(errmsg("truncate cascades to table \"%s\"",
RelationGetRelationName(rel))));
truncate_check_rel(rel);
rels = lappend(rels, rel);
relids = lappend_oid(relids, relid);
}
}
}
/*
* Check foreign key references. In CASCADE mode, this should be
* unnecessary since we just pulled in all the references; but as a
* cross-check, do it anyway if in an Assert-enabled build.
*/
#ifdef USE_ASSERT_CHECKING
heap_truncate_check_FKs(rels, false);
#else
if (stmt->behavior == DROP_RESTRICT)
heap_truncate_check_FKs(rels, false);
#endif
/*
* Also check for pending AFTER trigger events on the target relations. We
* can't just leave those be, since they will try to fetch tuples that the
* TRUNCATE removes.
*/
AfterTriggerCheckTruncate(relids);
/*
* OK, truncate each table.
*/
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
Oid heap_relid;
Oid toast_relid;
/*
* Create a new empty storage file for the relation, and assign it as
* the relfilenode value. The old storage file is scheduled for
* deletion at commit.
*/
setNewRelfilenode(rel);
heap_relid = RelationGetRelid(rel);
toast_relid = rel->rd_rel->reltoastrelid;
heap_close(rel, NoLock);
/*
* The same for the toast table, if any.
*/
if (OidIsValid(toast_relid))
{
rel = relation_open(toast_relid, AccessExclusiveLock);
setNewRelfilenode(rel);
heap_close(rel, NoLock);
}
/*
* Reconstruct the indexes to match, and we're done.
*/
reindex_relation(heap_relid, true);
}
}
/*
* Check that a given rel is safe to truncate. Subroutine for ExecuteTruncate
*/
static void
truncate_check_rel(Relation rel)
{
/* Only allow truncate on regular tables */
if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
/*
* We can never allow truncation of shared or nailed-in-cache relations,
* because we can't support changing their relfilenode values.
*/
if (rel->rd_rel->relisshared || rel->rd_isnailed)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot truncate system relation \"%s\"",
RelationGetRelationName(rel))));
/*
* Don't allow truncate on temp tables of other backends ... their local
* buffer manager is not going to cope.
*/
if (isOtherTempNamespace(RelationGetNamespace(rel)))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot truncate temporary tables of other sessions")));
}
/*----------
* MergeAttributes
* Returns new schema given initial schema and superclasses.
*
* Input arguments:
* 'schema' is the column/attribute definition for the table. (It's a list
* of ColumnDef's.) It is destructively changed.
* 'supers' is a list of names (as RangeVar nodes) of parent relations.
* 'istemp' is TRUE if we are creating a temp relation.
*
* Output arguments:
* 'supOids' receives a list of the OIDs of the parent relations.
* 'supconstr' receives a list of constraints belonging to the parents,
* updated as necessary to be valid for the child.
* 'supOidCount' is set to the number of parents that have OID columns.
*
* Return value:
* Completed schema list.
*
* Notes:
* The order in which the attributes are inherited is very important.
* Intuitively, the inherited attributes should come first. If a table
* inherits from multiple parents, the order of those attributes are
* according to the order of the parents specified in CREATE TABLE.
*
* Here's an example:
*
* create table person (name text, age int4, location point);
* create table emp (salary int4, manager text) inherits(person);
* create table student (gpa float8) inherits (person);
* create table stud_emp (percent int4) inherits (emp, student);
*
* The order of the attributes of stud_emp is:
*
* person {1:name, 2:age, 3:location}
* / \
* {6:gpa} student emp {4:salary, 5:manager}
* \ /
* stud_emp {7:percent}
*
* If the same attribute name appears multiple times, then it appears
* in the result table in the proper location for its first appearance.
*
* Constraints (including NOT NULL constraints) for the child table
* are the union of all relevant constraints, from both the child schema
* and parent tables.
*
* The default value for a child column is defined as:
* (1) If the child schema specifies a default, that value is used.
* (2) If neither the child nor any parent specifies a default, then
* the column will not have a default.
* (3) If conflicting defaults are inherited from different parents
* (and not overridden by the child), an error is raised.
* (4) Otherwise the inherited default is used.
* Rule (3) is new in Postgres 7.1; in earlier releases you got a
* rather arbitrary choice of which parent default to use.
*----------
*/
static List *
MergeAttributes(List *schema, List *supers, bool istemp,
List **supOids, List **supconstr, int *supOidCount)
{
ListCell *entry;
List *inhSchema = NIL;
List *parentOids = NIL;
List *constraints = NIL;
int parentsWithOids = 0;
bool have_bogus_defaults = false;
char *bogus_marker = "Bogus!"; /* marks conflicting defaults */
int child_attno;
/*
* Check for and reject tables with too many columns. We perform this
* check relatively early for two reasons: (a) we don't run the risk of
* overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
* okay if we're processing <= 1600 columns, but could take minutes to
* execute if the user attempts to create a table with hundreds of
* thousands of columns.
*
* Note that we also need to check that any we do not exceed this figure
* after including columns from inherited relations.
*/
if (list_length(schema) > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
/*
* Check for duplicate names in the explicit list of attributes.
*
* Although we might consider merging such entries in the same way that we
* handle name conflicts for inherited attributes, it seems to make more
* sense to assume such conflicts are errors.
*/
foreach(entry, schema)
{
ColumnDef *coldef = lfirst(entry);
ListCell *rest;
for_each_cell(rest, lnext(entry))
{
ColumnDef *restdef = lfirst(rest);
if (strcmp(coldef->colname, restdef->colname) == 0)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" duplicated",
coldef->colname)));
}
}
/*
* Scan the parents left-to-right, and merge their attributes to form a
* list of inherited attributes (inhSchema). Also check to see if we need
* to inherit an OID column.
*/
child_attno = 0;
foreach(entry, supers)
{
RangeVar *parent = (RangeVar *) lfirst(entry);
Relation relation;
TupleDesc tupleDesc;
TupleConstr *constr;
AttrNumber *newattno;
AttrNumber parent_attno;
relation = heap_openrv(parent, AccessShareLock);
if (relation->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("inherited relation \"%s\" is not a table",
parent->relname)));
/* Permanent rels cannot inherit from temporary ones */
if (!istemp && isTempNamespace(RelationGetNamespace(relation)))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot inherit from temporary relation \"%s\"",
parent->relname)));
/*
* We should have an UNDER permission flag for this, but for now,
* demand that creator of a child table own the parent.
*/
if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(relation));
/*
* Reject duplications in the list of parents.
*/
if (list_member_oid(parentOids, RelationGetRelid(relation)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("inherited relation \"%s\" duplicated",
parent->relname)));
parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
if (relation->rd_rel->relhasoids)
parentsWithOids++;
tupleDesc = RelationGetDescr(relation);
constr = tupleDesc->constr;
/*
* newattno[] will contain the child-table attribute numbers for the
* attributes of this parent table. (They are not the same for
* parents after the first one, nor if we have dropped columns.)
*/
newattno = (AttrNumber *)
palloc(tupleDesc->natts * sizeof(AttrNumber));
for (parent_attno = 1; parent_attno <= tupleDesc->natts;
parent_attno++)
{
Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
char *attributeName = NameStr(attribute->attname);
int exist_attno;
ColumnDef *def;
/*
* Ignore dropped columns in the parent.
*/
if (attribute->attisdropped)
{
/*
* change_varattnos_of_a_node asserts that this is greater
* than zero, so if anything tries to use it, we should find
* out.
*/
newattno[parent_attno - 1] = 0;
continue;
}
/*
* Does it conflict with some previously inherited column?
*/
exist_attno = findAttrByName(attributeName, inhSchema);
if (exist_attno > 0)
{
Oid defTypeId;
int32 deftypmod;
/*
* Yes, try to merge the two column definitions. They must
* have the same type and typmod.
*/
ereport(NOTICE,
(errmsg("merging multiple inherited definitions of column \"%s\"",
attributeName)));
def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
defTypeId = typenameTypeId(NULL, def->typename);
deftypmod = typenameTypeMod(NULL, def->typename, defTypeId);
if (defTypeId != attribute->atttypid ||
deftypmod != attribute->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("inherited column \"%s\" has a type conflict",
attributeName),
errdetail("%s versus %s",
TypeNameToString(def->typename),
format_type_be(attribute->atttypid))));
def->inhcount++;
/* Merge of NOT NULL constraints = OR 'em together */
def->is_not_null |= attribute->attnotnull;
/* Default and other constraints are handled below */
newattno[parent_attno - 1] = exist_attno;
}
else
{
/*
* No, create a new inherited column
*/
def = makeNode(ColumnDef);
def->colname = pstrdup(attributeName);
def->typename = makeTypeNameFromOid(attribute->atttypid,
attribute->atttypmod);
def->inhcount = 1;
def->is_local = false;
def->is_not_null = attribute->attnotnull;
def->raw_default = NULL;
def->cooked_default = NULL;
def->constraints = NIL;
inhSchema = lappend(inhSchema, def);
newattno[parent_attno - 1] = ++child_attno;
}
/*
* Copy default if any
*/
if (attribute->atthasdef)
{
char *this_default = NULL;
AttrDefault *attrdef;
int i;
/* Find default in constraint structure */
Assert(constr != NULL);
attrdef = constr->defval;
for (i = 0; i < constr->num_defval; i++)
{
if (attrdef[i].adnum == parent_attno)
{
this_default = attrdef[i].adbin;
break;
}
}
Assert(this_default != NULL);
/*
* If default expr could contain any vars, we'd need to fix
* 'em, but it can't; so default is ready to apply to child.
*
* If we already had a default from some prior parent, check
* to see if they are the same. If so, no problem; if not,
* mark the column as having a bogus default. Below, we will
* complain if the bogus default isn't overridden by the child
* schema.
*/
Assert(def->raw_default == NULL);
if (def->cooked_default == NULL)
def->cooked_default = pstrdup(this_default);
else if (strcmp(def->cooked_default, this_default) != 0)
{
def->cooked_default = bogus_marker;
have_bogus_defaults = true;
}
}
}
/*
* Now copy the constraints of this parent, adjusting attnos using the
* completed newattno[] map
*/
if (constr && constr->num_check > 0)
{
ConstrCheck *check = constr->check;
int i;
for (i = 0; i < constr->num_check; i++)
{
Constraint *cdef = makeNode(Constraint);
Node *expr;
cdef->contype = CONSTR_CHECK;
cdef->name = pstrdup(check[i].ccname);
cdef->raw_expr = NULL;
/* adjust varattnos of ccbin here */
expr = stringToNode(check[i].ccbin);
change_varattnos_of_a_node(expr, newattno);
cdef->cooked_expr = nodeToString(expr);
constraints = lappend(constraints, cdef);
}
}
pfree(newattno);
/*
* Close the parent rel, but keep our AccessShareLock on it until xact
* commit. That will prevent someone else from deleting or ALTERing
* the parent before the child is committed.
*/
heap_close(relation, NoLock);
}
/*
* If we had no inherited attributes, the result schema is just the
* explicitly declared columns. Otherwise, we need to merge the declared
* columns into the inherited schema list.
*/
if (inhSchema != NIL)
{
foreach(entry, schema)
{
ColumnDef *newdef = lfirst(entry);
char *attributeName = newdef->colname;
int exist_attno;
/*
* Does it conflict with some previously inherited column?
*/
exist_attno = findAttrByName(attributeName, inhSchema);
if (exist_attno > 0)
{
ColumnDef *def;
Oid defTypeId, newTypeId;
int32 deftypmod, newtypmod;
/*
* Yes, try to merge the two column definitions. They must
* have the same type and typmod.
*/
ereport(NOTICE,
(errmsg("merging column \"%s\" with inherited definition",
attributeName)));
def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
defTypeId = typenameTypeId(NULL, def->typename);
deftypmod = typenameTypeMod(NULL, def->typename, defTypeId);
newTypeId = typenameTypeId(NULL, newdef->typename);
newtypmod = typenameTypeMod(NULL, newdef->typename, newTypeId);
if (defTypeId != newTypeId || deftypmod != newtypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" has a type conflict",
attributeName),
errdetail("%s versus %s",
TypeNameToString(def->typename),
TypeNameToString(newdef->typename))));
/* Mark the column as locally defined */
def->is_local = true;
/* Merge of NOT NULL constraints = OR 'em together */
def->is_not_null |= newdef->is_not_null;
/* If new def has a default, override previous default */
if (newdef->raw_default != NULL)
{
def->raw_default = newdef->raw_default;
def->cooked_default = newdef->cooked_default;
}
}
else
{
/*
* No, attach new column to result schema
*/
inhSchema = lappend(inhSchema, newdef);
}
}
schema = inhSchema;
/*
* Check that we haven't exceeded the legal # of columns after merging
* in inherited columns.
*/
if (list_length(schema) > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
}
/*
* If we found any conflicting parent default values, check to make sure
* they were overridden by the child.
*/
if (have_bogus_defaults)
{
foreach(entry, schema)
{
ColumnDef *def = lfirst(entry);
if (def->cooked_default == bogus_marker)
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
errmsg("column \"%s\" inherits conflicting default values",
def->colname),
errhint("To resolve the conflict, specify a default explicitly.")));
}
}
*supOids = parentOids;
*supconstr = constraints;
*supOidCount = parentsWithOids;
return schema;
}
/*
* In multiple-inheritance situations, it's possible to inherit
* the same grandparent constraint through multiple parents.
* Hence, we want to discard inherited constraints that match as to
* both name and expression. Otherwise, gripe if there are conflicting
* names. Nonconflicting constraints are added to the array check[]
* of length *ncheck ... caller must ensure there is room!
*/
static void
add_nonduplicate_constraint(Constraint *cdef, ConstrCheck *check, int *ncheck)
{
int i;
/* Should only see precooked constraints here */
Assert(cdef->contype == CONSTR_CHECK);
Assert(cdef->name != NULL);
Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
for (i = 0; i < *ncheck; i++)
{
if (strcmp(check[i].ccname, cdef->name) != 0)
continue;
if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0)
return; /* duplicate constraint, so ignore it */
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("duplicate check constraint name \"%s\"",
cdef->name)));
}
/* No match on name, so add it to array */
check[*ncheck].ccname = cdef->name;
check[*ncheck].ccbin = pstrdup(cdef->cooked_expr);
(*ncheck)++;
}
/*
* Replace varattno values in an expression tree according to the given
* map array, that is, varattno N is replaced by newattno[N-1]. It is
* caller's responsibility to ensure that the array is long enough to
* define values for all user varattnos present in the tree. System column
* attnos remain unchanged.
*
* Note that the passed node tree is modified in-place!
*/
void
change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
{
/* no setup needed, so away we go */
(void) change_varattnos_walker(node, newattno);
}
static bool
change_varattnos_walker(Node *node, const AttrNumber *newattno)
{
if (node == NULL)
return false;
if (IsA(node, Var))
{
Var *var = (Var *) node;
if (var->varlevelsup == 0 && var->varno == 1 &&
var->varattno > 0)
{
/*
* ??? the following may be a problem when the node is multiply
* referenced though stringToNode() doesn't create such a node
* currently.
*/
Assert(newattno[var->varattno - 1] > 0);
var->varattno = newattno[var->varattno - 1];
}
return false;
}
return expression_tree_walker(node, change_varattnos_walker,
(void *) newattno);
}
/*
* Generate a map for change_varattnos_of_a_node from old and new TupleDesc's,
* matching according to column name.
*/
AttrNumber *
varattnos_map(TupleDesc old, TupleDesc new)
{
AttrNumber *attmap;
int i,
j;
attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts);
for (i = 1; i <= old->natts; i++)
{
if (old->attrs[i - 1]->attisdropped)
continue; /* leave the entry as zero */
for (j = 1; j <= new->natts; j++)
{
if (strcmp(NameStr(old->attrs[i - 1]->attname),
NameStr(new->attrs[j - 1]->attname)) == 0)
{
attmap[i - 1] = j;
break;
}
}
}
return attmap;
}
/*
* Generate a map for change_varattnos_of_a_node from a TupleDesc and a list
* of ColumnDefs
*/
AttrNumber *
varattnos_map_schema(TupleDesc old, List *schema)
{
AttrNumber *attmap;
int i;
attmap = (AttrNumber *) palloc0(sizeof(AttrNumber) * old->natts);
for (i = 1; i <= old->natts; i++)
{
if (old->attrs[i - 1]->attisdropped)
continue; /* leave the entry as zero */
attmap[i - 1] = findAttrByName(NameStr(old->attrs[i - 1]->attname),
schema);
}
return attmap;
}
/*
* StoreCatalogInheritance
* Updates the system catalogs with proper inheritance information.
*
* supers is a list of the OIDs of the new relation's direct ancestors.
*/
static void
StoreCatalogInheritance(Oid relationId, List *supers)
{
Relation relation;
int16 seqNumber;
ListCell *entry;
/*
* sanity checks
*/
AssertArg(OidIsValid(relationId));
if (supers == NIL)
return;
/*
* Store INHERITS information in pg_inherits using direct ancestors only.
* Also enter dependencies on the direct ancestors, and make sure they are
* marked with relhassubclass = true.
*
* (Once upon a time, both direct and indirect ancestors were found here
* and then entered into pg_ipl. Since that catalog doesn't exist
* anymore, there's no need to look for indirect ancestors.)
*/
relation = heap_open(InheritsRelationId, RowExclusiveLock);
seqNumber = 1;
foreach(entry, supers)
{
Oid parentOid = lfirst_oid(entry);
StoreCatalogInheritance1(relationId, parentOid, seqNumber, relation);
seqNumber++;
}
heap_close(relation, RowExclusiveLock);
}
/*
* Make catalog entries showing relationId as being an inheritance child
* of parentOid. inhRelation is the already-opened pg_inherits catalog.
*/
static void
StoreCatalogInheritance1(Oid relationId, Oid parentOid,
int16 seqNumber, Relation inhRelation)
{
TupleDesc desc = RelationGetDescr(inhRelation);
Datum datum[Natts_pg_inherits];
char nullarr[Natts_pg_inherits];
ObjectAddress childobject,
parentobject;
HeapTuple tuple;
/*
* Make the pg_inherits entry
*/
datum[0] = ObjectIdGetDatum(relationId); /* inhrelid */
datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */
datum[2] = Int16GetDatum(seqNumber); /* inhseqno */
nullarr[0] = ' ';
nullarr[1] = ' ';
nullarr[2] = ' ';
tuple = heap_formtuple(desc, datum, nullarr);
simple_heap_insert(inhRelation, tuple);
CatalogUpdateIndexes(inhRelation, tuple);
heap_freetuple(tuple);
/*
* Store a dependency too
*/
parentobject.classId = RelationRelationId;
parentobject.objectId = parentOid;
parentobject.objectSubId = 0;
childobject.classId = RelationRelationId;
childobject.objectId = relationId;
childobject.objectSubId = 0;
recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);
/*
* Mark the parent as having subclasses.
*/
setRelhassubclassInRelation(parentOid, true);
}
/*
* Look for an existing schema entry with the given name.
*
* Returns the index (starting with 1) if attribute already exists in schema,
* 0 if it doesn't.
*/
static int
findAttrByName(const char *attributeName, List *schema)
{
ListCell *s;
int i = 1;
foreach(s, schema)
{
ColumnDef *def = lfirst(s);
if (strcmp(attributeName, def->colname) == 0)
return i;
i++;
}
return 0;
}
/*
* Update a relation's pg_class.relhassubclass entry to the given value
*/
static void
setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
{
Relation relationRelation;
HeapTuple tuple;
Form_pg_class classtuple;
/*
* Fetch a modifiable copy of the tuple, modify it, update pg_class.
*
* If the tuple already has the right relhassubclass setting, we don't
* need to update it, but we still need to issue an SI inval message.
*/
relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(relationId),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationId);
classtuple = (Form_pg_class) GETSTRUCT(tuple);
if (classtuple->relhassubclass != relhassubclass)
{
classtuple->relhassubclass = relhassubclass;
simple_heap_update(relationRelation, &tuple->t_self, tuple);
/* keep the catalog indexes up to date */
CatalogUpdateIndexes(relationRelation, tuple);
}
else
{
/* no need to change tuple, but force relcache rebuild anyway */
CacheInvalidateRelcacheByTuple(tuple);
}
heap_freetuple(tuple);
heap_close(relationRelation, RowExclusiveLock);
}
/*
* renameatt - changes the name of a attribute in a relation
*
* Attname attribute is changed in attribute catalog.
* No record of the previous attname is kept (correct?).
*
* get proper relrelation from relation catalog (if not arg)
* scan attribute catalog
* for name conflict (within rel)
* for original attribute (if not arg)
* modify attname in attribute tuple
* insert modified attribute in attribute catalog
* delete original attribute from attribute catalog
*/
void
renameatt(Oid myrelid,
const char *oldattname,
const char *newattname,
bool recurse,
bool recursing)
{
Relation targetrelation;
Relation attrelation;
HeapTuple atttup;
Form_pg_attribute attform;
int attnum;
List *indexoidlist;
ListCell *indexoidscan;
/*
* Grab an exclusive lock on the target table, which we will NOT release
* until end of transaction.
*/
targetrelation = relation_open(myrelid, AccessExclusiveLock);
/*
* permissions checking. this would normally be done in utility.c, but
* this particular routine is recursive.
*
* normally, only the owner of a class can change its schema.
*/
if (!pg_class_ownercheck(myrelid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(targetrelation));
if (!allowSystemTableMods && IsSystemRelation(targetrelation))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(targetrelation))));
/*
* if the 'recurse' flag is set then we are supposed to rename this
* attribute in all classes that inherit from 'relname' (as well as in
* 'relname').
*
* any permissions or problems with duplicate attributes will cause the
* whole transaction to abort, which is what we want -- all or nothing.
*/
if (recurse)
{
ListCell *child;
List *children;
/* this routine is actually in the planner */
children = find_all_inheritors(myrelid);
/*
* find_all_inheritors does the recursive search of the inheritance
* hierarchy, so all we have to do is process all of the relids in the
* list that it returns.
*/
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
if (childrelid == myrelid)
continue;
/* note we need not recurse again */
renameatt(childrelid, oldattname, newattname, false, true);
}
}
else
{
/*
* If we are told not to recurse, there had better not be any child
* tables; else the rename would put them out of step.
*/
if (!recursing &&
find_inheritance_children(myrelid) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("inherited column \"%s\" must be renamed in child tables too",
oldattname)));
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
if (!HeapTupleIsValid(atttup))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
oldattname)));
attform = (Form_pg_attribute) GETSTRUCT(atttup);
attnum = attform->attnum;
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rename system column \"%s\"",
oldattname)));
/*
* if the attribute is inherited, forbid the renaming, unless we are
* already inside a recursive rename.
*/
if (attform->attinhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot rename inherited column \"%s\"",
oldattname)));
/* should not already exist */
/* this test is deliberately not attisdropped-aware */
if (SearchSysCacheExists(ATTNAME,
ObjectIdGetDatum(myrelid),
PointerGetDatum(newattname),
0, 0))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" of relation \"%s\" already exists",
newattname, RelationGetRelationName(targetrelation))));
namestrcpy(&(attform->attname), newattname);
simple_heap_update(attrelation, &atttup->t_self, atttup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, atttup);
heap_freetuple(atttup);
/*
* Update column names of indexes that refer to the column being renamed.
*/
indexoidlist = RelationGetIndexList(targetrelation);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
HeapTuple indextup;
Form_pg_index indexform;
int i;
/*
* Scan through index columns to see if there's any simple index
* entries for this attribute. We ignore expressional entries.
*/
indextup = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(indexoid),
0, 0, 0);
if (!HeapTupleIsValid(indextup))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexform = (Form_pg_index) GETSTRUCT(indextup);
for (i = 0; i < indexform->indnatts; i++)
{
if (attnum != indexform->indkey.values[i])
continue;
/*
* Found one, rename it.
*/
atttup = SearchSysCacheCopy(ATTNUM,
ObjectIdGetDatum(indexoid),
Int16GetDatum(i + 1),
0, 0);
if (!HeapTupleIsValid(atttup))
continue; /* should we raise an error? */
/*
* Update the (copied) attribute tuple.
*/
namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
newattname);
simple_heap_update(attrelation, &atttup->t_self, atttup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, atttup);
heap_freetuple(atttup);
}
ReleaseSysCache(indextup);
}
list_free(indexoidlist);
heap_close(attrelation, RowExclusiveLock);
relation_close(targetrelation, NoLock); /* close rel but keep lock */
}
/*
* renamerel - change the name of a relation
*
* XXX - When renaming sequences, we don't bother to modify the
* sequence name that is stored within the sequence itself
* (this would cause problems with MVCC). In the future,
* the sequence name should probably be removed from the
* sequence, AFAIK there's no need for it to be there.
*/
void
renamerel(Oid myrelid, const char *newrelname)
{
Relation targetrelation;
Relation relrelation; /* for RELATION relation */
HeapTuple reltup;
Oid namespaceId;
char *oldrelname;
char relkind;
bool relhastriggers;
/*
* Grab an exclusive lock on the target table or index, which we will NOT
* release until end of transaction.
*/
targetrelation = relation_open(myrelid, AccessExclusiveLock);
oldrelname = pstrdup(RelationGetRelationName(targetrelation));
namespaceId = RelationGetNamespace(targetrelation);
if (!allowSystemTableMods && IsSystemRelation(targetrelation))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(targetrelation))));
relkind = targetrelation->rd_rel->relkind;
relhastriggers = (targetrelation->rd_rel->reltriggers > 0);
/*
* Find relation's pg_class tuple, and make sure newrelname isn't in use.
*/
relrelation = heap_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy(RELOID,
PointerGetDatum(myrelid),
0, 0, 0);
if (!HeapTupleIsValid(reltup)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for relation %u", myrelid);
if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists",
newrelname)));
/*
* Update pg_class tuple with new relname. (Scribbling on reltup is OK
* because it's a copy...)
*/
namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);
simple_heap_update(relrelation, &reltup->t_self, reltup);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(relrelation, reltup);
heap_freetuple(reltup);
heap_close(relrelation, RowExclusiveLock);
/*
* Also rename the associated type, if any.
*/
if (relkind != RELKIND_INDEX)
TypeRename(oldrelname, namespaceId, newrelname);
/*
* Close rel, but keep exclusive lock!
*/
relation_close(targetrelation, NoLock);
}
/*
* AlterTable
* Execute ALTER TABLE, which can be a list of subcommands
*
* ALTER TABLE is performed in three phases:
* 1. Examine subcommands and perform pre-transformation checking.
* 2. Update system catalogs.
* 3. Scan table(s) to check new constraints, and optionally recopy
* the data into new table(s).
* Phase 3 is not performed unless one or more of the subcommands requires
* it. The intention of this design is to allow multiple independent
* updates of the table schema to be performed with only one pass over the
* data.
*
* ATPrepCmd performs phase 1. A "work queue" entry is created for
* each table to be affected (there may be multiple affected tables if the
* commands traverse a table inheritance hierarchy). Also we do preliminary
* validation of the subcommands, including parse transformation of those
* expressions that need to be evaluated with respect to the old table
* schema.
*
* ATRewriteCatalogs performs phase 2 for each affected table (note that
* phases 2 and 3 do no explicit recursion, since phase 1 already did it).
* Certain subcommands need to be performed before others to avoid
* unnecessary conflicts; for example, DROP COLUMN should come before
* ADD COLUMN. Therefore phase 1 divides the subcommands into multiple
* lists, one for each logical "pass" of phase 2.
*
* ATRewriteTables performs phase 3 for those tables that need it.
*
* Thanks to the magic of MVCC, an error anywhere along the way rolls back
* the whole operation; we don't have to do anything special to clean up.
*/
void
AlterTable(AlterTableStmt *stmt)
{
Relation rel = relation_openrv(stmt->relation, AccessExclusiveLock);
int expected_refcnt;
/*
* Disallow ALTER TABLE when the current backend has any open reference
* to it besides the one we just got (such as an open cursor or active
* plan); our AccessExclusiveLock doesn't protect us against stomping on
* our own foot, only other people's feet!
*
* Note: the only case known to cause serious trouble is ALTER COLUMN TYPE,
* and some changes are obviously pretty benign, so this could possibly
* be relaxed to only error out for certain types of alterations. But
* the use-case for allowing any of these things is not obvious, so we
* won't work hard at it for now.
*/
expected_refcnt = rel->rd_isnailed ? 2 : 1;
if (rel->rd_refcnt != expected_refcnt)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("relation \"%s\" is being used by active queries in this session",
RelationGetRelationName(rel))));
ATController(rel, stmt->cmds, interpretInhOption(stmt->relation->inhOpt));
}
/*
* AlterTableInternal
*
* ALTER TABLE with target specified by OID
*
* We do not reject if the relation is already open, because it's quite
* likely that one or more layers of caller have it open. That means it
* is unsafe to use this entry point for alterations that could break
* existing query plans.
*/
void
AlterTableInternal(Oid relid, List *cmds, bool recurse)
{
Relation rel = relation_open(relid, AccessExclusiveLock);
ATController(rel, cmds, recurse);
}
static void
ATController(Relation rel, List *cmds, bool recurse)
{
List *wqueue = NIL;
ListCell *lcmd;
/* Phase 1: preliminary examination of commands, create work queue */
foreach(lcmd, cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
ATPrepCmd(&wqueue, rel, cmd, recurse, false);
}
/* Close the relation, but keep lock until commit */
relation_close(rel, NoLock);
/* Phase 2: update system catalogs */
ATRewriteCatalogs(&wqueue);
/* Phase 3: scan/rewrite tables as needed */
ATRewriteTables(&wqueue);
}
/*
* ATPrepCmd
*
* Traffic cop for ALTER TABLE Phase 1 operations, including simple
* recursion and permission checks.
*
* Caller must have acquired AccessExclusiveLock on relation already.
* This lock should be held until commit.
*/
static void
ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
bool recurse, bool recursing)
{
AlteredTableInfo *tab;
int pass;
/* Find or create work queue entry for this table */
tab = ATGetQueueEntry(wqueue, rel);
/*
* Copy the original subcommand for each table. This avoids conflicts
* when different child tables need to make different parse
* transformations (for example, the same column may have different column
* numbers in different children).
*/
cmd = copyObject(cmd);
/*
* Do permissions checking, recursion to child tables if needed, and any
* additional phase-1 processing needed.
*/
switch (cmd->subtype)
{
case AT_AddColumn: /* ADD COLUMN */
ATSimplePermissions(rel, false);
/* Performs own recursion */
ATPrepAddColumn(wqueue, rel, recurse, cmd);
pass = AT_PASS_ADD_COL;
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
/*
* We allow defaults on views so that INSERT into a view can have
* default-ish behavior. This works because the rewriter
* substitutes default values into INSERTs before it expands
* rules.
*/
ATSimplePermissions(rel, true);
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP;
break;
case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = AT_PASS_DROP;
break;
case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = AT_PASS_ADD_CONSTR;
break;
case AT_SetStatistics: /* ALTER COLUMN STATISTICS */
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* Performs own permission checks */
ATPrepSetStatistics(rel, cmd->name, cmd->def);
pass = AT_PASS_COL_ATTRS;
break;
case AT_SetStorage: /* ALTER COLUMN STORAGE */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = AT_PASS_COL_ATTRS;
break;
case AT_DropColumn: /* DROP COLUMN */
ATSimplePermissions(rel, false);
/* Recursion occurs during execution phase */
/* No command-specific prep needed except saving recurse flag */
if (recurse)
cmd->subtype = AT_DropColumnRecurse;
pass = AT_PASS_DROP;
break;
case AT_AddIndex: /* ADD INDEX */
ATSimplePermissions(rel, false);
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_ADD_INDEX;
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
ATSimplePermissions(rel, false);
/*
* Currently we recurse only for CHECK constraints, never for
* foreign-key constraints. UNIQUE/PKEY constraints won't be seen
* here.
*/
if (IsA(cmd->def, Constraint))
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = AT_PASS_ADD_CONSTR;
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
ATSimplePermissions(rel, false);
/* Performs own recursion */
ATPrepDropConstraint(wqueue, rel, recurse, cmd);
pass = AT_PASS_DROP;
break;
case AT_DropConstraintQuietly: /* DROP CONSTRAINT for child */
ATSimplePermissions(rel, false);
ATSimpleRecursion(wqueue, rel, cmd, recurse);
/* No command-specific prep needed */
pass = AT_PASS_DROP;
break;
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
ATSimplePermissions(rel, false);
/* Performs own recursion */
ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd);
pass = AT_PASS_ALTER_TYPE;
break;
case AT_ChangeOwner: /* ALTER OWNER */
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_ClusterOn: /* CLUSTER ON */
case AT_DropCluster: /* SET WITHOUT CLUSTER */
ATSimplePermissions(rel, false);
/* These commands never recurse */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_DropOids: /* SET WITHOUT OIDS */
ATSimplePermissions(rel, false);
/* Performs own recursion */
if (rel->rd_rel->relhasoids)
{
AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
dropCmd->subtype = AT_DropColumn;
dropCmd->name = pstrdup("oid");
dropCmd->behavior = cmd->behavior;
ATPrepCmd(wqueue, rel, dropCmd, recurse, false);
}
pass = AT_PASS_DROP;
break;
case AT_SetTableSpace: /* SET TABLESPACE */
ATSimplePermissionsRelationOrIndex(rel);
/* This command never recurses */
ATPrepSetTableSpace(tab, rel, cmd->name);
pass = AT_PASS_MISC; /* doesn't actually matter */
break;
case AT_SetRelOptions: /* SET (...) */
case AT_ResetRelOptions: /* RESET (...) */
ATSimplePermissionsRelationOrIndex(rel);
/* This command never recurses */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
case AT_EnableTrig: /* ENABLE TRIGGER variants */
case AT_EnableAlwaysTrig:
case AT_EnableReplicaTrig:
case AT_EnableTrigAll:
case AT_EnableTrigUser:
case AT_DisableTrig: /* DISABLE TRIGGER variants */
case AT_DisableTrigAll:
case AT_DisableTrigUser:
case AT_EnableRule: /* ENABLE/DISABLE RULE variants */
case AT_EnableAlwaysRule:
case AT_EnableReplicaRule:
case AT_DisableRule:
case AT_AddInherit: /* INHERIT / NO INHERIT */
case AT_DropInherit:
ATSimplePermissions(rel, false);
/* These commands never recurse */
/* No command-specific prep needed */
pass = AT_PASS_MISC;
break;
default: /* oops */
elog(ERROR, "unrecognized alter table type: %d",
(int) cmd->subtype);
pass = 0; /* keep compiler quiet */
break;
}
/* Add the subcommand to the appropriate list for phase 2 */
tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd);
}
/*
* ATRewriteCatalogs
*
* Traffic cop for ALTER TABLE Phase 2 operations. Subcommands are
* dispatched in a "safe" execution order (designed to avoid unnecessary
* conflicts).
*/
static void
ATRewriteCatalogs(List **wqueue)
{
int pass;
ListCell *ltab;
/*
* We process all the tables "in parallel", one pass at a time. This is
* needed because we may have to propagate work from one table to another
* (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
* re-adding of the foreign key constraint to the other table). Work can
* only be propagated into later passes, however.
*/
for (pass = 0; pass < AT_NUM_PASSES; pass++)
{
/* Go through each table that needs to be processed */
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
List *subcmds = tab->subcmds[pass];
Relation rel;
ListCell *lcmd;
if (subcmds == NIL)
continue;
/*
* Exclusive lock was obtained by phase 1, needn't get it again
*/
rel = relation_open(tab->relid, NoLock);
foreach(lcmd, subcmds)
ATExecCmd(tab, rel, (AlterTableCmd *) lfirst(lcmd));
/*
* After the ALTER TYPE pass, do cleanup work (this is not done in
* ATExecAlterColumnType since it should be done only once if
* multiple columns of a table are altered).
*/
if (pass == AT_PASS_ALTER_TYPE)
ATPostAlterTypeCleanup(wqueue, tab);
relation_close(rel, NoLock);
}
}
/*
* Check to see if a toast table must be added, if we executed any
* subcommands that might have added a column or changed column storage.
*/
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
if (tab->relkind == RELKIND_RELATION &&
(tab->subcmds[AT_PASS_ADD_COL] ||
tab->subcmds[AT_PASS_ALTER_TYPE] ||
tab->subcmds[AT_PASS_COL_ATTRS]))
AlterTableCreateToastTable(tab->relid);
}
}
/*
* ATExecCmd: dispatch a subcommand to appropriate execution routine
*/
static void
ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd)
{
switch (cmd->subtype)
{
case AT_AddColumn: /* ADD COLUMN */
ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def);
break;
case AT_ColumnDefault: /* ALTER COLUMN DEFAULT */
ATExecColumnDefault(rel, cmd->name, cmd->def);
break;
case AT_DropNotNull: /* ALTER COLUMN DROP NOT NULL */
ATExecDropNotNull(rel, cmd->name);
break;
case AT_SetNotNull: /* ALTER COLUMN SET NOT NULL */
ATExecSetNotNull(tab, rel, cmd->name);
break;
case AT_SetStatistics: /* ALTER COLUMN STATISTICS */
ATExecSetStatistics(rel, cmd->name, cmd->def);
break;
case AT_SetStorage: /* ALTER COLUMN STORAGE */
ATExecSetStorage(rel, cmd->name, cmd->def);
break;
case AT_DropColumn: /* DROP COLUMN */
ATExecDropColumn(rel, cmd->name, cmd->behavior, false, false);
break;
case AT_DropColumnRecurse: /* DROP COLUMN with recursion */
ATExecDropColumn(rel, cmd->name, cmd->behavior, true, false);
break;
case AT_AddIndex: /* ADD INDEX */
ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false);
break;
case AT_ReAddIndex: /* ADD INDEX */
ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true);
break;
case AT_AddConstraint: /* ADD CONSTRAINT */
ATExecAddConstraint(tab, rel, cmd->def);
break;
case AT_DropConstraint: /* DROP CONSTRAINT */
ATExecDropConstraint(rel, cmd->name, cmd->behavior, false);
break;
case AT_DropConstraintQuietly: /* DROP CONSTRAINT for child */
ATExecDropConstraint(rel, cmd->name, cmd->behavior, true);
break;
case AT_AlterColumnType: /* ALTER COLUMN TYPE */
ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def);
break;
case AT_ChangeOwner: /* ALTER OWNER */
ATExecChangeOwner(RelationGetRelid(rel),
get_roleid_checked(cmd->name),
false);
break;
case AT_ClusterOn: /* CLUSTER ON */
ATExecClusterOn(rel, cmd->name);
break;
case AT_DropCluster: /* SET WITHOUT CLUSTER */
ATExecDropCluster(rel);
break;
case AT_DropOids: /* SET WITHOUT OIDS */
/*
* Nothing to do here; we'll have generated a DropColumn
* subcommand to do the real work
*/
break;
case AT_SetTableSpace: /* SET TABLESPACE */
/*
* Nothing to do here; Phase 3 does the work
*/
break;
case AT_SetRelOptions: /* SET (...) */
ATExecSetRelOptions(rel, (List *) cmd->def, false);
break;
case AT_ResetRelOptions: /* RESET (...) */
ATExecSetRelOptions(rel, (List *) cmd->def, true);
break;
case AT_EnableTrig: /* ENABLE TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ON_ORIGIN, false);
break;
case AT_EnableAlwaysTrig: /* ENABLE ALWAYS TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ALWAYS, false);
break;
case AT_EnableReplicaTrig: /* ENABLE REPLICA TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_FIRES_ON_REPLICA, false);
break;
case AT_DisableTrig: /* DISABLE TRIGGER name */
ATExecEnableDisableTrigger(rel, cmd->name,
TRIGGER_DISABLED, false);
break;
case AT_EnableTrigAll: /* ENABLE TRIGGER ALL */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_FIRES_ON_ORIGIN, false);
break;
case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_DISABLED, false);
break;
case AT_EnableTrigUser: /* ENABLE TRIGGER USER */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_FIRES_ON_ORIGIN, true);
break;
case AT_DisableTrigUser: /* DISABLE TRIGGER USER */
ATExecEnableDisableTrigger(rel, NULL,
TRIGGER_DISABLED, true);
break;
case AT_EnableRule: /* ENABLE RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ON_ORIGIN);
break;
case AT_EnableAlwaysRule: /* ENABLE ALWAYS RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ALWAYS);
break;
case AT_EnableReplicaRule: /* ENABLE REPLICA RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_FIRES_ON_REPLICA);
break;
case AT_DisableRule: /* DISABLE RULE name */
ATExecEnableDisableRule(rel, cmd->name,
RULE_DISABLED);
break;
case AT_AddInherit:
ATExecAddInherit(rel, (RangeVar *) cmd->def);
break;
case AT_DropInherit:
ATExecDropInherit(rel, (RangeVar *) cmd->def);
break;
default: /* oops */
elog(ERROR, "unrecognized alter table type: %d",
(int) cmd->subtype);
break;
}
/*
* Bump the command counter to ensure the next subcommand in the sequence
* can see the changes so far
*/
CommandCounterIncrement();
}
/*
* ATRewriteTables: ALTER TABLE phase 3
*/
static void
ATRewriteTables(List **wqueue)
{
ListCell *ltab;
/* Go through each table that needs to be checked or rewritten */
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
/*
* We only need to rewrite the table if at least one column needs to
* be recomputed.
*/
if (tab->newvals != NIL)
{
/* Build a temporary relation and copy data */
Oid OIDNewHeap;
char NewHeapName[NAMEDATALEN];
Oid NewTableSpace;
Relation OldHeap;
ObjectAddress object;
OldHeap = heap_open(tab->relid, NoLock);
/*
* We can never allow rewriting of shared or nailed-in-cache
* relations, because we can't support changing their relfilenode
* values.
*/
if (OldHeap->rd_rel->relisshared || OldHeap->rd_isnailed)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rewrite system relation \"%s\"",
RelationGetRelationName(OldHeap))));
/*
* Don't allow rewrite on temp tables of other backends ... their
* local buffer manager is not going to cope.
*/
if (isOtherTempNamespace(RelationGetNamespace(OldHeap)))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot rewrite temporary tables of other sessions")));
/*
* Select destination tablespace (same as original unless user
* requested a change)
*/
if (tab->newTableSpace)
NewTableSpace = tab->newTableSpace;
else
NewTableSpace = OldHeap->rd_rel->reltablespace;
heap_close(OldHeap, NoLock);
/*
* Create the new heap, using a temporary name in the same
* namespace as the existing table. NOTE: there is some risk of
* collision with user relnames. Working around this seems more
* trouble than it's worth; in particular, we can't create the new
* heap in a different namespace from the old, or we will have
* problems with the TEMP status of temp tables.
*/
snprintf(NewHeapName, sizeof(NewHeapName),
"pg_temp_%u", tab->relid);
OIDNewHeap = make_new_heap(tab->relid, NewHeapName, NewTableSpace);
/*
* Copy the heap data into the new table with the desired
* modifications, and test the current data within the table
* against new constraints generated by ALTER TABLE commands.
*/
ATRewriteTable(tab, OIDNewHeap);
/* Swap the physical files of the old and new heaps. */
swap_relation_files(tab->relid, OIDNewHeap);
CommandCounterIncrement();
/* Destroy new heap with old filenode */
object.classId = RelationRelationId;
object.objectId = OIDNewHeap;
object.objectSubId = 0;
/*
* The new relation is local to our transaction and we know
* nothing depends on it, so DROP_RESTRICT should be OK.
*/
performDeletion(&object, DROP_RESTRICT);
/* performDeletion does CommandCounterIncrement at end */
/*
* Rebuild each index on the relation (but not the toast table,
* which is all-new anyway). We do not need
* CommandCounterIncrement() because reindex_relation does it.
*/
reindex_relation(tab->relid, false);
}
else
{
/*
* Test the current data within the table against new constraints
* generated by ALTER TABLE commands, but don't rebuild data.
*/
if (tab->constraints != NIL || tab->new_notnull)
ATRewriteTable(tab, InvalidOid);
/*
* If we had SET TABLESPACE but no reason to reconstruct tuples,
* just do a block-by-block copy.
*/
if (tab->newTableSpace)
ATExecSetTableSpace(tab->relid, tab->newTableSpace);
}
}
/*
* Foreign key constraints are checked in a final pass, since (a) it's
* generally best to examine each one separately, and (b) it's at least
* theoretically possible that we have changed both relations of the
* foreign key, and we'd better have finished both rewrites before we try
* to read the tables.
*/
foreach(ltab, *wqueue)
{
AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
Relation rel = NULL;
ListCell *lcon;
foreach(lcon, tab->constraints)
{
NewConstraint *con = lfirst(lcon);
if (con->contype == CONSTR_FOREIGN)
{
FkConstraint *fkconstraint = (FkConstraint *) con->qual;
Relation refrel;
if (rel == NULL)
{
/* Long since locked, no need for another */
rel = heap_open(tab->relid, NoLock);
}
refrel = heap_open(con->refrelid, RowShareLock);
validateForeignKeyConstraint(fkconstraint, rel, refrel,
con->conid);
heap_close(refrel, NoLock);
}
}
if (rel)
heap_close(rel, NoLock);
}
}
/*
* ATRewriteTable: scan or rewrite one table
*
* OIDNewHeap is InvalidOid if we don't need to rewrite
*/
static void
ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
{
Relation oldrel;
Relation newrel;
TupleDesc oldTupDesc;
TupleDesc newTupDesc;
bool needscan = false;
List *notnull_attrs;
int i;
ListCell *l;
EState *estate;
/*
* Open the relation(s). We have surely already locked the existing
* table.
*/
oldrel = heap_open(tab->relid, NoLock);
oldTupDesc = tab->oldDesc;
newTupDesc = RelationGetDescr(oldrel); /* includes all mods */
if (OidIsValid(OIDNewHeap))
newrel = heap_open(OIDNewHeap, AccessExclusiveLock);
else
newrel = NULL;
/*
* If we need to rewrite the table, the operation has to be propagated to
* tables that use this table's rowtype as a column type.
*
* (Eventually this will probably become true for scans as well, but at
* the moment a composite type does not enforce any constraints, so it's
* not necessary/appropriate to enforce them just during ALTER.)
*/
if (newrel)
find_composite_type_dependencies(oldrel->rd_rel->reltype,
RelationGetRelationName(oldrel));
/*
* Generate the constraint and default execution states
*/
estate = CreateExecutorState();
/* Build the needed expression execution states */
foreach(l, tab->constraints)
{
NewConstraint *con = lfirst(l);
switch (con->contype)
{
case CONSTR_CHECK:
needscan = true;
con->qualstate = (List *)
ExecPrepareExpr((Expr *) con->qual, estate);
break;
case CONSTR_FOREIGN:
/* Nothing to do here */
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) con->contype);
}
}
foreach(l, tab->newvals)
{
NewColumnValue *ex = lfirst(l);
needscan = true;
ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate);
}
notnull_attrs = NIL;
if (newrel || tab->new_notnull)
{
/*
* If we are rebuilding the tuples OR if we added any new NOT NULL
* constraints, check all not-null constraints. This is a bit of
* overkill but it minimizes risk of bugs, and heap_attisnull is a
* pretty cheap test anyway.
*/
for (i = 0; i < newTupDesc->natts; i++)
{
if (newTupDesc->attrs[i]->attnotnull &&
!newTupDesc->attrs[i]->attisdropped)
notnull_attrs = lappend_int(notnull_attrs, i);
}
if (notnull_attrs)
needscan = true;
}
if (needscan)
{
ExprContext *econtext;
Datum *values;
bool *isnull;
TupleTableSlot *oldslot;
TupleTableSlot *newslot;
HeapScanDesc scan;
HeapTuple tuple;
MemoryContext oldCxt;
List *dropped_attrs = NIL;
ListCell *lc;
econtext = GetPerTupleExprContext(estate);
/*
* Make tuple slots for old and new tuples. Note that even when the
* tuples are the same, the tupDescs might not be (consider ADD COLUMN
* without a default).
*/
oldslot = MakeSingleTupleTableSlot(oldTupDesc);
newslot = MakeSingleTupleTableSlot(newTupDesc);
/* Preallocate values/isnull arrays */
i = Max(newTupDesc->natts, oldTupDesc->natts);
values = (Datum *) palloc(i * sizeof(Datum));
isnull = (bool *) palloc(i * sizeof(bool));
memset(values, 0, i * sizeof(Datum));
memset(isnull, true, i * sizeof(bool));
/*
* Any attributes that are dropped according to the new tuple
* descriptor can be set to NULL. We precompute the list of dropped
* attributes to avoid needing to do so in the per-tuple loop.
*/
for (i = 0; i < newTupDesc->natts; i++)
{
if (newTupDesc->attrs[i]->attisdropped)
dropped_attrs = lappend_int(dropped_attrs, i);
}
/*
* Scan through the rows, generating a new row if needed and then
* checking all the constraints.
*/
scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL);
/*
* Switch to per-tuple memory context and reset it for each tuple
* produced, so we don't leak memory.
*/
oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
if (newrel)
{
Oid tupOid = InvalidOid;
/* Extract data from old tuple */
heap_deform_tuple(tuple, oldTupDesc, values, isnull);
if (oldTupDesc->tdhasoid)
tupOid = HeapTupleGetOid(tuple);
/* Set dropped attributes to null in new tuple */
foreach(lc, dropped_attrs)
isnull[lfirst_int(lc)] = true;
/*
* Process supplied expressions to replace selected columns.
* Expression inputs come from the old tuple.
*/
ExecStoreTuple(tuple, oldslot, InvalidBuffer, false);
econtext->ecxt_scantuple = oldslot;
foreach(l, tab->newvals)
{
NewColumnValue *ex = lfirst(l);
values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate,
econtext,
&isnull[ex->attnum - 1],
NULL);
}
/*
* Form the new tuple. Note that we don't explicitly pfree it,
* since the per-tuple memory context will be reset shortly.
*/
tuple = heap_form_tuple(newTupDesc, values, isnull);
/* Preserve OID, if any */
if (newTupDesc->tdhasoid)
HeapTupleSetOid(tuple, tupOid);
}
/* Now check any constraints on the possibly-changed tuple */
ExecStoreTuple(tuple, newslot, InvalidBuffer, false);
econtext->ecxt_scantuple = newslot;
foreach(l, notnull_attrs)
{
int attn = lfirst_int(l);
if (heap_attisnull(tuple, attn + 1))
ereport(ERROR,
(errcode(ERRCODE_NOT_NULL_VIOLATION),
errmsg("column \"%s\" contains null values",
NameStr(newTupDesc->attrs[attn]->attname))));
}
foreach(l, tab->constraints)
{
NewConstraint *con = lfirst(l);
switch (con->contype)
{
case CONSTR_CHECK:
if (!ExecQual(con->qualstate, econtext, true))
ereport(ERROR,
(errcode(ERRCODE_CHECK_VIOLATION),
errmsg("check constraint \"%s\" is violated by some row",
con->name)));
break;
case CONSTR_FOREIGN:
/* Nothing to do here */
break;
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) con->contype);
}
}
/* Write the tuple out to the new relation */
if (newrel)
simple_heap_insert(newrel, tuple);
ResetExprContext(econtext);
CHECK_FOR_INTERRUPTS();
}
MemoryContextSwitchTo(oldCxt);
heap_endscan(scan);
ExecDropSingleTupleTableSlot(oldslot);
ExecDropSingleTupleTableSlot(newslot);
}
FreeExecutorState(estate);
heap_close(oldrel, NoLock);
if (newrel)
heap_close(newrel, NoLock);
}
/*
* ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
*/
static AlteredTableInfo *
ATGetQueueEntry(List **wqueue, Relation rel)
{
Oid relid = RelationGetRelid(rel);
AlteredTableInfo *tab;
ListCell *ltab;
foreach(ltab, *wqueue)
{
tab = (AlteredTableInfo *) lfirst(ltab);
if (tab->relid == relid)
return tab;
}
/*
* Not there, so add it. Note that we make a copy of the relation's
* existing descriptor before anything interesting can happen to it.
*/
tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
tab->relid = relid;
tab->relkind = rel->rd_rel->relkind;
tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
*wqueue = lappend(*wqueue, tab);
return tab;
}
/*
* ATSimplePermissions
*
* - Ensure that it is a relation (or possibly a view)
* - Ensure this user is the owner
* - Ensure that it is not a system table
*/
static void
ATSimplePermissions(Relation rel, bool allowView)
{
if (rel->rd_rel->relkind != RELKIND_RELATION)
{
if (allowView)
{
if (rel->rd_rel->relkind != RELKIND_VIEW)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or view",
RelationGetRelationName(rel))));
}
else
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
}
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
}
/*
* ATSimplePermissionsRelationOrIndex
*
* - Ensure that it is a relation or an index
* - Ensure this user is the owner
* - Ensure that it is not a system table
*/
static void
ATSimplePermissionsRelationOrIndex(Relation rel)
{
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
RelationGetRelationName(rel))));
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
if (!allowSystemTableMods && IsSystemRelation(rel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(rel))));
}
/*
* ATSimpleRecursion
*
* Simple table recursion sufficient for most ALTER TABLE operations.
* All direct and indirect children are processed in an unspecified order.
* Note that if a child inherits from the original table via multiple
* inheritance paths, it will be visited just once.
*/
static void
ATSimpleRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd, bool recurse)
{
/*
* Propagate to children if desired. Non-table relations never have
* children, so no need to search in that case.
*/
if (recurse && rel->rd_rel->relkind == RELKIND_RELATION)
{
Oid relid = RelationGetRelid(rel);
ListCell *child;
List *children;
/* this routine is actually in the planner */
children = find_all_inheritors(relid);
/*
* find_all_inheritors does the recursive search of the inheritance
* hierarchy, so all we have to do is process all of the relids in the
* list that it returns.
*/
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
if (childrelid == relid)
continue;
childrel = relation_open(childrelid, AccessExclusiveLock);
/* check for child relation in use in this session */
if (childrel->rd_refcnt != 1)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("relation \"%s\" is being used by active queries in this session",
RelationGetRelationName(childrel))));
ATPrepCmd(wqueue, childrel, cmd, false, true);
relation_close(childrel, NoLock);
}
}
}
/*
* ATOneLevelRecursion
*
* Here, we visit only direct inheritance children. It is expected that
* the command's prep routine will recurse again to find indirect children.
* When using this technique, a multiply-inheriting child will be visited
* multiple times.
*/
static void
ATOneLevelRecursion(List **wqueue, Relation rel,
AlterTableCmd *cmd)
{
Oid relid = RelationGetRelid(rel);
ListCell *child;
List *children;
/* this routine is actually in the planner */
children = find_inheritance_children(relid);
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
childrel = relation_open(childrelid, AccessExclusiveLock);
/* check for child relation in use in this session */
if (childrel->rd_refcnt != 1)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("relation \"%s\" is being used by active queries in this session",
RelationGetRelationName(childrel))));
ATPrepCmd(wqueue, childrel, cmd, true, true);
relation_close(childrel, NoLock);
}
}
/*
* find_composite_type_dependencies
*
* Check to see if a table's rowtype is being used as a column in some
* other table (possibly nested several levels deep in composite types!).
* Eventually, we'd like to propagate the check or rewrite operation
* into other such tables, but for now, just error out if we find any.
*
* We assume that functions and views depending on the type are not reasons
* to reject the ALTER. (How safe is this really?)
*/
static void
find_composite_type_dependencies(Oid typeOid, const char *origTblName)
{
Relation depRel;
ScanKeyData key[2];
SysScanDesc depScan;
HeapTuple depTup;
Oid arrayOid;
/*
* We scan pg_depend to find those things that depend on the rowtype. (We
* assume we can ignore refobjsubid for a rowtype.)
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(TypeRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(typeOid));
depScan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(depTup = systable_getnext(depScan)))
{
Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup);
Relation rel;
Form_pg_attribute att;
/* Ignore dependees that aren't user columns of relations */
/* (we assume system columns are never of rowtypes) */
if (pg_depend->classid != RelationRelationId ||
pg_depend->objsubid <= 0)
continue;
rel = relation_open(pg_depend->objid, AccessShareLock);
att = rel->rd_att->attrs[pg_depend->objsubid - 1];
if (rel->rd_rel->relkind == RELKIND_RELATION)
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
origTblName,
RelationGetRelationName(rel),
NameStr(att->attname))));
}
else if (OidIsValid(rel->rd_rel->reltype))
{
/*
* A view or composite type itself isn't a problem, but we must
* recursively check for indirect dependencies via its rowtype.
*/
find_composite_type_dependencies(rel->rd_rel->reltype,
origTblName);
}
relation_close(rel, AccessShareLock);
}
systable_endscan(depScan);
relation_close(depRel, AccessShareLock);
/*
* If there's an array type for the rowtype, must check for uses of it,
* too.
*/
arrayOid = get_array_type(typeOid);
if (OidIsValid(arrayOid))
find_composite_type_dependencies(arrayOid, origTblName);
}
/*
* ALTER TABLE ADD COLUMN
*
* Adds an additional attribute to a relation making the assumption that
* CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
* AT_AddColumn AlterTableCmd by analyze.c and added as independent
* AlterTableCmd's.
*/
static void
ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
AlterTableCmd *cmd)
{
/*
* Recurse to add the column to child classes, if requested.
*
* We must recurse one level at a time, so that multiply-inheriting
* children are visited the right number of times and end up with the
* right attinhcount.
*/
if (recurse)
{
AlterTableCmd *childCmd = copyObject(cmd);
ColumnDef *colDefChild = (ColumnDef *) childCmd->def;
/* Child should see column as singly inherited */
colDefChild->inhcount = 1;
colDefChild->is_local = false;
ATOneLevelRecursion(wqueue, rel, childCmd);
}
else
{
/*
* If we are told not to recurse, there had better not be any child
* tables; else the addition would put them out of step.
*/
if (find_inheritance_children(RelationGetRelid(rel)) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column must be added to child tables too")));
}
}
static void
ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
ColumnDef *colDef)
{
Oid myrelid = RelationGetRelid(rel);
Relation pgclass,
attrdesc;
HeapTuple reltup;
HeapTuple attributeTuple;
Form_pg_attribute attribute;
FormData_pg_attribute attributeD;
int i;
int minattnum,
maxatts;
HeapTuple typeTuple;
Oid typeOid;
int32 typmod;
Form_pg_type tform;
Expr *defval;
attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
/*
* Are we adding the column to a recursion child? If so, check whether to
* merge with an existing definition for the column.
*/
if (colDef->inhcount > 0)
{
HeapTuple tuple;
/* Does child already have a column by this name? */
tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname);
if (HeapTupleIsValid(tuple))
{
Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
Oid ctypeId;
int32 ctypmod;
/* Okay if child matches by type */
ctypeId = typenameTypeId(NULL, colDef->typename);
ctypmod = typenameTypeMod(NULL, colDef->typename, ctypeId);
if (ctypeId != childatt->atttypid ||
ctypmod != childatt->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has different type for column \"%s\"",
RelationGetRelationName(rel), colDef->colname)));
/* Bump the existing child att's inhcount */
childatt->attinhcount++;
simple_heap_update(attrdesc, &tuple->t_self, tuple);
CatalogUpdateIndexes(attrdesc, tuple);
heap_freetuple(tuple);
/* Inform the user about the merge */
ereport(NOTICE,
(errmsg("merging definition of column \"%s\" for child \"%s\"",
colDef->colname, RelationGetRelationName(rel))));
heap_close(attrdesc, RowExclusiveLock);
return;
}
}
pgclass = heap_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(myrelid),
0, 0, 0);
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", myrelid);
/*
* this test is deliberately not attisdropped-aware, since if one tries to
* add a column matching a dropped column name, it's gonna fail anyway.
*/
if (SearchSysCacheExists(ATTNAME,
ObjectIdGetDatum(myrelid),
PointerGetDatum(colDef->colname),
0, 0))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_COLUMN),
errmsg("column \"%s\" of relation \"%s\" already exists",
colDef->colname, RelationGetRelationName(rel))));
minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
maxatts = minattnum + 1;
if (maxatts > MaxHeapAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("tables can have at most %d columns",
MaxHeapAttributeNumber)));
i = minattnum + 1;
typeTuple = typenameType(NULL, colDef->typename);
tform = (Form_pg_type) GETSTRUCT(typeTuple);
typeOid = HeapTupleGetOid(typeTuple);
typmod = typenameTypeMod(NULL, colDef->typename, typeOid);
/* make sure datatype is legal for a column */
CheckAttributeType(colDef->colname, typeOid);
attributeTuple = heap_addheader(Natts_pg_attribute,
false,
ATTRIBUTE_TUPLE_SIZE,
(void *) &attributeD);
attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple);
attribute->attrelid = myrelid;
namestrcpy(&(attribute->attname), colDef->colname);
attribute->atttypid = typeOid;
attribute->attstattarget = -1;
attribute->attlen = tform->typlen;
attribute->attcacheoff = -1;
attribute->atttypmod = typmod;
attribute->attnum = i;
attribute->attbyval = tform->typbyval;
attribute->attndims = list_length(colDef->typename->arrayBounds);
attribute->attstorage = tform->typstorage;
attribute->attalign = tform->typalign;
attribute->attnotnull = colDef->is_not_null;
attribute->atthasdef = false;
attribute->attisdropped = false;
attribute->attislocal = colDef->is_local;
attribute->attinhcount = colDef->inhcount;
ReleaseSysCache(typeTuple);
simple_heap_insert(attrdesc, attributeTuple);
/* Update indexes on pg_attribute */
CatalogUpdateIndexes(attrdesc, attributeTuple);
heap_close(attrdesc, RowExclusiveLock);
/*
* Update number of attributes in pg_class tuple
*/
((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts;
simple_heap_update(pgclass, &reltup->t_self, reltup);
/* keep catalog indexes current */
CatalogUpdateIndexes(pgclass, reltup);
heap_freetuple(reltup);
heap_close(pgclass, RowExclusiveLock);
/* Make the attribute's catalog entry visible */
CommandCounterIncrement();
/*
* Store the DEFAULT, if any, in the catalogs
*/
if (colDef->raw_default)
{
RawColumnDefault *rawEnt;
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attribute->attnum;
rawEnt->raw_default = copyObject(colDef->raw_default);
/*
* This function is intended for CREATE TABLE, so it processes a
* _list_ of defaults, but we just do one.
*/
AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
/* Make the additional catalog changes visible */
CommandCounterIncrement();
}
/*
* Tell Phase 3 to fill in the default expression, if there is one.
*
* If there is no default, Phase 3 doesn't have to do anything, because
* that effectively means that the default is NULL. The heap tuple access
* routines always check for attnum > # of attributes in tuple, and return
* NULL if so, so without any modification of the tuple data we will get
* the effect of NULL values in the new column.
*
* An exception occurs when the new column is of a domain type: the domain
* might have a NOT NULL constraint, or a check constraint that indirectly
* rejects nulls. If there are any domain constraints then we construct
* an explicit NULL default value that will be passed through
* CoerceToDomain processing. (This is a tad inefficient, since it causes
* rewriting the table which we really don't have to do, but the present
* design of domain processing doesn't offer any simple way of checking
* the constraints more directly.)
*
* Note: we use build_column_default, and not just the cooked default
* returned by AddRelationRawConstraints, so that the right thing happens
* when a datatype's default applies.
*/
defval = (Expr *) build_column_default(rel, attribute->attnum);
if (!defval && GetDomainConstraints(typeOid) != NIL)
{
Oid basetype = getBaseType(typeOid);
defval = (Expr *) makeNullConst(basetype);
defval = (Expr *) coerce_to_target_type(NULL,
(Node *) defval,
basetype,
typeOid,
typmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST);
if (defval == NULL) /* should not happen */
elog(ERROR, "failed to coerce base type to domain");
}
if (defval)
{
NewColumnValue *newval;
newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
newval->attnum = attribute->attnum;
newval->expr = defval;
tab->newvals = lappend(tab->newvals, newval);
}
/*
* Add needed dependency entries for the new column.
*/
add_column_datatype_dependency(myrelid, i, attribute->atttypid);
}
/*
* Install a column's dependency on its datatype.
*/
static void
add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid)
{
ObjectAddress myself,
referenced;
myself.classId = RelationRelationId;
myself.objectId = relid;
myself.objectSubId = attnum;
referenced.classId = TypeRelationId;
referenced.objectId = typid;
referenced.objectSubId = 0;
recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
}
/*
* ALTER TABLE ALTER COLUMN DROP NOT NULL
*/
static void
ATExecDropNotNull(Relation rel, const char *colName)
{
HeapTuple tuple;
AttrNumber attnum;
Relation attr_rel;
List *indexoidlist;
ListCell *indexoidscan;
/*
* lookup the attribute
*/
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Check that the attribute is not in a primary key
*/
/* Loop over all indexes on the relation */
indexoidlist = RelationGetIndexList(rel);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
HeapTuple indexTuple;
Form_pg_index indexStruct;
int i;
indexTuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(indexoid),
0, 0, 0);
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
/* If the index is not a primary key, skip the check */
if (indexStruct->indisprimary)
{
/*
* Loop over each attribute in the primary key and see if it
* matches the to-be-altered attribute
*/
for (i = 0; i < indexStruct->indnatts; i++)
{
if (indexStruct->indkey.values[i] == attnum)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("column \"%s\" is in a primary key",
colName)));
}
}
ReleaseSysCache(indexTuple);
}
list_free(indexoidlist);
/*
* Okay, actually perform the catalog change ... if needed
*/
if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
{
((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET NOT NULL
*/
static void
ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
const char *colName)
{
HeapTuple tuple;
AttrNumber attnum;
Relation attr_rel;
/*
* lookup the attribute
*/
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Okay, actually perform the catalog change ... if needed
*/
if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
{
((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Tell Phase 3 it needs to test the constraint */
tab->new_notnull = true;
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
*/
static void
ATExecColumnDefault(Relation rel, const char *colName,
Node *newDefault)
{
AttrNumber attnum;
/*
* get the number of the attribute
*/
attnum = get_attnum(RelationGetRelid(rel), colName);
if (attnum == InvalidAttrNumber)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
/* Prevent them from altering a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* Remove any old default for the column. We use RESTRICT here for
* safety, but at present we do not expect anything to depend on the
* default.
*/
RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false);
if (newDefault)
{
/* SET DEFAULT */
RawColumnDefault *rawEnt;
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = newDefault;
/*
* This function is intended for CREATE TABLE, so it processes a
* _list_ of defaults, but we just do one.
*/
AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
}
}
/*
* ALTER TABLE ALTER COLUMN SET STATISTICS
*/
static void
ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue)
{
/*
* We do our own permission checking because (a) we want to allow SET
* STATISTICS on indexes (for expressional index columns), and (b) we want
* to allow SET STATISTICS on system catalogs without requiring
* allowSystemTableMods to be turned on.
*/
if (rel->rd_rel->relkind != RELKIND_RELATION &&
rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
RelationGetRelationName(rel))));
/* Permissions checks */
if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(rel));
}
static void
ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
{
int newtarget;
Relation attrelation;
HeapTuple tuple;
Form_pg_attribute attrtuple;
Assert(IsA(newValue, Integer));
newtarget = intVal(newValue);
/*
* Limit target to a sane range
*/
if (newtarget < -1)
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("statistics target %d is too low",
newtarget)));
}
else if (newtarget > 1000)
{
newtarget = 1000;
ereport(WARNING,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("lowering statistics target to %d",
newtarget)));
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
if (attrtuple->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
attrtuple->attstattarget = newtarget;
simple_heap_update(attrelation, &tuple->t_self, tuple);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, tuple);
heap_freetuple(tuple);
heap_close(attrelation, RowExclusiveLock);
}
/*
* ALTER TABLE ALTER COLUMN SET STORAGE
*/
static void
ATExecSetStorage(Relation rel, const char *colName, Node *newValue)
{
char *storagemode;
char newstorage;
Relation attrelation;
HeapTuple tuple;
Form_pg_attribute attrtuple;
Assert(IsA(newValue, String));
storagemode = strVal(newValue);
if (pg_strcasecmp(storagemode, "plain") == 0)
newstorage = 'p';
else if (pg_strcasecmp(storagemode, "external") == 0)
newstorage = 'e';
else if (pg_strcasecmp(storagemode, "extended") == 0)
newstorage = 'x';
else if (pg_strcasecmp(storagemode, "main") == 0)
newstorage = 'm';
else
{
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid storage type \"%s\"",
storagemode)));
newstorage = 0; /* keep compiler quiet */
}
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
if (attrtuple->attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/*
* safety check: do not allow toasted storage modes unless column datatype
* is TOAST-aware.
*/
if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
attrtuple->attstorage = newstorage;
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("column data type %s can only have storage PLAIN",
format_type_be(attrtuple->atttypid))));
simple_heap_update(attrelation, &tuple->t_self, tuple);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, tuple);
heap_freetuple(tuple);
heap_close(attrelation, RowExclusiveLock);
}
/*
* ALTER TABLE DROP COLUMN
*
* DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
* because we have to decide at runtime whether to recurse or not depending
* on whether attinhcount goes to zero or not. (We can't check this in a
* static pre-pass because it won't handle multiple inheritance situations
* correctly.) Since DROP COLUMN doesn't need to create any work queue
* entries for Phase 3, it's okay to recurse internally in this routine
* without considering the work queue.
*/
static void
ATExecDropColumn(Relation rel, const char *colName,
DropBehavior behavior,
bool recurse, bool recursing)
{
HeapTuple tuple;
Form_pg_attribute targetatt;
AttrNumber attnum;
List *children;
ObjectAddress object;
/* At top level, permission check was done in ATPrepCmd, else do it */
if (recursing)
ATSimplePermissions(rel, false);
/*
* get the number of the attribute
*/
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
targetatt = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = targetatt->attnum;
/* Can't drop a system attribute, except OID */
if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot drop system column \"%s\"",
colName)));
/* Don't drop inherited columns */
if (targetatt->attinhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot drop inherited column \"%s\"",
colName)));
ReleaseSysCache(tuple);
/*
* Propagate to children as appropriate. Unlike most other ALTER
* routines, we have to do this one level of recursion at a time; we can't
* use find_all_inheritors to do it in one pass.
*/
children = find_inheritance_children(RelationGetRelid(rel));
if (children)
{
Relation attr_rel;
ListCell *child;
attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
foreach(child, children)
{
Oid childrelid = lfirst_oid(child);
Relation childrel;
Form_pg_attribute childatt;
childrel = heap_open(childrelid, AccessExclusiveLock);
/* check for child relation in use in this session */
if (childrel->rd_refcnt != 1)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_IN_USE),
errmsg("relation \"%s\" is being used by active queries in this session",
RelationGetRelationName(childrel))));
tuple = SearchSysCacheCopyAttName(childrelid, colName);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
colName, childrelid);
childatt = (Form_pg_attribute) GETSTRUCT(tuple);
if (childatt->attinhcount <= 0) /* shouldn't happen */
elog(ERROR, "relation %u has non-inherited attribute \"%s\"",
childrelid, colName);
if (recurse)
{
/*
* If the child column has other definition sources, just
* decrement its inheritance count; if not, recurse to delete
* it.
*/
if (childatt->attinhcount == 1 && !childatt->attislocal)
{
/* Time to delete this child column, too */
ATExecDropColumn(childrel, colName, behavior, true, true);
}
else
{
/* Child column must survive my deletion */
childatt->attinhcount--;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Make update visible */
CommandCounterIncrement();
}
}
else
{
/*
* If we were told to drop ONLY in this table (no recursion),
* we need to mark the inheritors' attribute as locally
* defined rather than inherited.
*/
childatt->attinhcount--;
childatt->attislocal = true;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indexes current */
CatalogUpdateIndexes(attr_rel, tuple);
/* Make update visible */
CommandCounterIncrement();
}
heap_freetuple(tuple);
heap_close(childrel, NoLock);
}
heap_close(attr_rel, RowExclusiveLock);
}
/*
* Perform the actual column deletion
*/
object.classId = RelationRelationId;
object.objectId = RelationGetRelid(rel);
object.objectSubId = attnum;
performDeletion(&object, behavior);
/*
* If we dropped the OID column, must adjust pg_class.relhasoids
*/
if (attnum == ObjectIdAttributeNumber)
{
Relation class_rel;
Form_pg_class tuple_class;
class_rel = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(RelationGetRelid(rel)),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u",
RelationGetRelid(rel));
tuple_class = (Form_pg_class) GETSTRUCT(tuple);
tuple_class->relhasoids = false;
simple_heap_update(class_rel, &tuple->t_self, tuple);
/* Keep the catalog indexes up to date */
CatalogUpdateIndexes(class_rel, tuple);
heap_close(class_rel, RowExclusiveLock);
}
}
/*
* ALTER TABLE ADD INDEX
*
* There is no such command in the grammar, but the parser converts UNIQUE
* and PRIMARY KEY constraints into AT_AddIndex subcommands. This lets us
* schedule creation of the index at the appropriate time during ALTER.
*/
static void
ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
IndexStmt *stmt, bool is_rebuild)
{
bool check_rights;
bool skip_build;
bool quiet;
Assert(IsA(stmt, IndexStmt));
/* suppress schema rights check when rebuilding existing index */
check_rights = !is_rebuild;
/* skip index build if phase 3 will have to rewrite table anyway */
skip_build = (tab->newvals != NIL);
/* suppress notices when rebuilding existing index */
quiet = is_rebuild;
/*
* Run parse analysis. We don't have convenient access to the query text
* here, but it's probably not worth worrying about.
*/
stmt = analyzeIndexStmt(stmt, NULL);
/* ... and do it */
DefineIndex(stmt->relation, /* relation */
stmt->idxname, /* index name */
InvalidOid, /* no predefined OID */
stmt->accessMethod, /* am name */
stmt->tableSpace,
stmt->indexParams, /* parameters */
(Expr *) stmt->whereClause,
stmt->options,
stmt->unique,
stmt->primary,
stmt->isconstraint,
true, /* is_alter_table */
check_rights,
skip_build,
quiet,
false);
}
/*
* ALTER TABLE ADD CONSTRAINT
*/
static void
ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint)
{
switch (nodeTag(newConstraint))
{
case T_Constraint:
{
Constraint *constr = (Constraint *) newConstraint;
/*
* Currently, we only expect to see CONSTR_CHECK nodes
* arriving here (see the preprocessing done in
* parser/analyze.c). Use a switch anyway to make it easier
* to add more code later.
*/
switch (constr->contype)
{
case CONSTR_CHECK:
{
List *newcons;
ListCell *lcon;
/*
* Call AddRelationRawConstraints to do the work.
* It returns a list of cooked constraints.
*/
newcons = AddRelationRawConstraints(rel, NIL,
list_make1(constr));
/* Add each constraint to Phase 3's queue */
foreach(lcon, newcons)
{
CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon);
NewConstraint *newcon;
newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
newcon->name = ccon->name;
newcon->contype = ccon->contype;
/* ExecQual wants implicit-AND format */
newcon->qual = (Node *)
make_ands_implicit((Expr *) ccon->expr);
tab->constraints = lappend(tab->constraints,
newcon);
}
break;
}
default:
elog(ERROR, "unrecognized constraint type: %d",
(int) constr->contype);
}
break;
}
case T_FkConstraint:
{
FkConstraint *fkconstraint = (FkConstraint *) newConstraint;
/*
* Assign or validate constraint name
*/
if (fkconstraint->constr_name)
{
if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
RelationGetRelid(rel),
RelationGetNamespace(rel),
fkconstraint->constr_name))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_OBJECT),
errmsg("constraint \"%s\" for relation \"%s\" already exists",
fkconstraint->constr_name,
RelationGetRelationName(rel))));
}
else
fkconstraint->constr_name =
ChooseConstraintName(RelationGetRelationName(rel),
strVal(linitial(fkconstraint->fk_attrs)),
"fkey",
RelationGetNamespace(rel),
NIL);
ATAddForeignKeyConstraint(tab, rel, fkconstraint);
break;
}
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(newConstraint));
}
}
/*
* Add a foreign-key constraint to a single table
*
* Subroutine for ATExecAddConstraint. Must already hold exclusive
* lock on the rel, and have done appropriate validity/permissions checks
* for it.
*/
static void
ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
FkConstraint *fkconstraint)
{
Relation pkrel;
AclResult aclresult;
int16 pkattnum[INDEX_MAX_KEYS];
int16 fkattnum[INDEX_MAX_KEYS];
Oid pktypoid[INDEX_MAX_KEYS];
Oid fktypoid[INDEX_MAX_KEYS];
Oid opclasses[INDEX_MAX_KEYS];
Oid pfeqoperators[INDEX_MAX_KEYS];
Oid ppeqoperators[INDEX_MAX_KEYS];
Oid ffeqoperators[INDEX_MAX_KEYS];
int i;
int numfks,
numpks;
Oid indexOid;
Oid constrOid;
/*
* Grab an exclusive lock on the pk table, so that someone doesn't delete
* rows out from under us. (Although a lesser lock would do for that
* purpose, we'll need exclusive lock anyway to add triggers to the pk
* table; trying to start with a lesser lock will just create a risk of
* deadlock.)
*/
pkrel = heap_openrv(fkconstraint->pktable, AccessExclusiveLock);
/*
* Validity and permissions checks
*
* Note: REFERENCES permissions checks are redundant with CREATE TRIGGER,
* but we may as well error out sooner instead of later.
*/
if (pkrel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("referenced relation \"%s\" is not a table",
RelationGetRelationName(pkrel))));
aclresult = pg_class_aclcheck(RelationGetRelid(pkrel), GetUserId(),
ACL_REFERENCES);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(pkrel));
if (!allowSystemTableMods && IsSystemRelation(pkrel))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied: \"%s\" is a system catalog",
RelationGetRelationName(pkrel))));
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_REFERENCES);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
/*
* Disallow reference from permanent table to temp table or vice versa.
* (The ban on perm->temp is for fairly obvious reasons. The ban on
* temp->perm is because other backends might need to run the RI triggers
* on the perm table, but they can't reliably see tuples the owning
* backend has created in the temp table, because non-shared buffers are
* used for temp tables.)
*/
if (isTempNamespace(RelationGetNamespace(pkrel)))
{
if (!isTempNamespace(RelationGetNamespace(rel)))
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot reference temporary table from permanent table constraint")));
}
else
{
if (isTempNamespace(RelationGetNamespace(rel)))
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot reference permanent table from temporary table constraint")));
}
/*
* Look up the referencing attributes to make sure they exist, and record
* their attnums and type OIDs.
*/
MemSet(pkattnum, 0, sizeof(pkattnum));
MemSet(fkattnum, 0, sizeof(fkattnum));
MemSet(pktypoid, 0, sizeof(pktypoid));
MemSet(fktypoid, 0, sizeof(fktypoid));
MemSet(opclasses, 0, sizeof(opclasses));
MemSet(pfeqoperators, 0, sizeof(pfeqoperators));
MemSet(ppeqoperators, 0, sizeof(ppeqoperators));
MemSet(ffeqoperators, 0, sizeof(ffeqoperators));
numfks = transformColumnNameList(RelationGetRelid(rel),
fkconstraint->fk_attrs,
fkattnum, fktypoid);
/*
* If the attribute list for the referenced table was omitted, lookup the
* definition of the primary key and use it. Otherwise, validate the
* supplied attribute list. In either case, discover the index OID and
* index opclasses, and the attnums and type OIDs of the attributes.
*/
if (fkconstraint->pk_attrs == NIL)
{
numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid,
&fkconstraint->pk_attrs,
pkattnum, pktypoid,
opclasses);
}
else
{
numpks = transformColumnNameList(RelationGetRelid(pkrel),
fkconstraint->pk_attrs,
pkattnum, pktypoid);
/* Look for an index matching the column list */
indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum,
opclasses);
}
/*
* Look up the equality operators to use in the constraint.
*
* Note that we have to be careful about the difference between the actual
* PK column type and the opclass' declared input type, which might be
* only binary-compatible with it. The declared opcintype is the right
* thing to probe pg_amop with.
*/
if (numfks != numpks)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("number of referencing and referenced columns for foreign key disagree")));
for (i = 0; i < numpks; i++)
{
Oid pktype = pktypoid[i];
Oid fktype = fktypoid[i];
Oid fktyped;
HeapTuple cla_ht;
Form_pg_opclass cla_tup;
Oid amid;
Oid opfamily;
Oid opcintype;
Oid pfeqop;
Oid ppeqop;
Oid ffeqop;
int16 eqstrategy;
/* We need several fields out of the pg_opclass entry */
cla_ht = SearchSysCache(CLAOID,
ObjectIdGetDatum(opclasses[i]),
0, 0, 0);
if (!HeapTupleIsValid(cla_ht))
elog(ERROR, "cache lookup failed for opclass %u", opclasses[i]);
cla_tup = (Form_pg_opclass) GETSTRUCT(cla_ht);
amid = cla_tup->opcmethod;
opfamily = cla_tup->opcfamily;
opcintype = cla_tup->opcintype;
ReleaseSysCache(cla_ht);
/*
* Check it's a btree; currently this can never fail since no other
* index AMs support unique indexes. If we ever did have other
* types of unique indexes, we'd need a way to determine which
* operator strategy number is equality. (Is it reasonable to
* insist that every such index AM use btree's number for equality?)
*/
if (amid != BTREE_AM_OID)
elog(ERROR, "only b-tree indexes are supported for foreign keys");
eqstrategy = BTEqualStrategyNumber;
/*
* There had better be a primary equality operator for the index.
* We'll use it for PK = PK comparisons.
*/
ppeqop = get_opfamily_member(opfamily, opcintype, opcintype,
eqstrategy);
if (!OidIsValid(ppeqop))
elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
eqstrategy, opcintype, opcintype, opfamily);
/*
* Are there equality operators that take exactly the FK type?
* Assume we should look through any domain here.
*/
fktyped = getBaseType(fktype);
pfeqop = get_opfamily_member(opfamily, opcintype, fktyped,
eqstrategy);
if (OidIsValid(pfeqop))
ffeqop = get_opfamily_member(opfamily, fktyped, fktyped,
eqstrategy);
else
ffeqop = InvalidOid; /* keep compiler quiet */
if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
{
/*
* Otherwise, look for an implicit cast from the FK type to
* the opcintype, and if found, use the primary equality operator.
* This is a bit tricky because opcintype might be a generic type
* such as ANYARRAY, and so what we have to test is whether the
* two actual column types can be concurrently cast to that type.
* (Otherwise, we'd fail to reject combinations such as int[] and
* point[].)
*/
Oid input_typeids[2];
Oid target_typeids[2];
input_typeids[0] = pktype;
input_typeids[1] = fktype;
target_typeids[0] = opcintype;
target_typeids[1] = opcintype;
if (can_coerce_type(2, input_typeids, target_typeids,
COERCION_IMPLICIT))
pfeqop = ffeqop = ppeqop;
}
if (!(OidIsValid(pfeqop) && OidIsValid(ffeqop)))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("foreign key constraint \"%s\" "
"cannot be implemented",
fkconstraint->constr_name),
errdetail("Key columns \"%s\" and \"%s\" "
"are of incompatible types: %s and %s.",
strVal(list_nth(fkconstraint->fk_attrs, i)),
strVal(list_nth(fkconstraint->pk_attrs, i)),
format_type_be(fktype),
format_type_be(pktype))));
pfeqoperators[i] = pfeqop;
ppeqoperators[i] = ppeqop;
ffeqoperators[i] = ffeqop;
}
/*
* Record the FK constraint in pg_constraint.
*/
constrOid = CreateConstraintEntry(fkconstraint->constr_name,
RelationGetNamespace(rel),
CONSTRAINT_FOREIGN,
fkconstraint->deferrable,
fkconstraint->initdeferred,
RelationGetRelid(rel),
fkattnum,
numfks,
InvalidOid, /* not a domain
* constraint */
RelationGetRelid(pkrel),
pkattnum,
pfeqoperators,
ppeqoperators,
ffeqoperators,
numpks,
fkconstraint->fk_upd_action,
fkconstraint->fk_del_action,
fkconstraint->fk_matchtype,
indexOid,
NULL, /* no check constraint */
NULL,
NULL);
/*
* Create the triggers that will enforce the constraint.
*/
createForeignKeyTriggers(rel, fkconstraint, constrOid);
/*
* Tell Phase 3 to check that the constraint is satisfied by existing rows
* (we can skip this during table creation).
*/
if (!fkconstraint->skip_validation)
{
NewConstraint *newcon;
newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
newcon->name = fkconstraint->constr_name;
newcon->contype = CONSTR_FOREIGN;
newcon->refrelid = RelationGetRelid(pkrel);
newcon->conid = constrOid;
newcon->qual = (Node *) fkconstraint;
tab->constraints = lappend(tab->constraints, newcon);
}
/*
* Close pk table, but keep lock until we've committed.
*/
heap_close(pkrel, NoLock);
}
/*
* transformColumnNameList - transform list of column names
*
* Lookup each name and return its attnum and type OID
*/
static int
transformColumnNameList(Oid relId, List *colList,
int16 *attnums, Oid *atttypids)
{
ListCell *l;
int attnum;
attnum = 0;
foreach(l, colList)
{
char *attname = strVal(lfirst(l));
HeapTuple atttuple;
atttuple = SearchSysCacheAttName(relId, attname);
if (!HeapTupleIsValid(atttuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" referenced in foreign key constraint does not exist",
attname)));
if (attnum >= INDEX_MAX_KEYS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_COLUMNS),
errmsg("cannot have more than %d keys in a foreign key",
INDEX_MAX_KEYS)));
attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
ReleaseSysCache(atttuple);
attnum++;
}
return attnum;
}
/*
* transformFkeyGetPrimaryKey -
*
* Look up the names, attnums, and types of the primary key attributes
* for the pkrel. Also return the index OID and index opclasses of the
* index supporting the primary key.
*
* All parameters except pkrel are output parameters. Also, the function
* return value is the number of attributes in the primary key.
*
* Used when the column list in the REFERENCES specification is omitted.
*/
static int
transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
List **attnamelist,
int16 *attnums, Oid *atttypids,
Oid *opclasses)
{
List *indexoidlist;
ListCell *indexoidscan;
HeapTuple indexTuple = NULL;
Form_pg_index indexStruct = NULL;
Datum indclassDatum;
bool isnull;
oidvector *indclass;
int i;
/*
* Get the list of index OIDs for the table from the relcache, and look up
* each one in the pg_index syscache until we find one marked primary key
* (hopefully there isn't more than one such).
*/
*indexOid = InvalidOid;
indexoidlist = RelationGetIndexList(pkrel);
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirst_oid(indexoidscan);
indexTuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(indexoid),
0, 0, 0);
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
if (indexStruct->indisprimary)
{
*indexOid = indexoid;
break;
}
ReleaseSysCache(indexTuple);
}
list_free(indexoidlist);
/*
* Check that we found it
*/
if (!OidIsValid(*indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("there is no primary key for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
/* Must get indclass the hard way */
indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
Anum_pg_index_indclass, &isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* Now build the list of PK attributes from the indkey definition (we
* assume a primary key cannot have expressional elements)
*/
*attnamelist = NIL;
for (i = 0; i < indexStruct->indnatts; i++)
{
int pkattno = indexStruct->indkey.values[i];
attnums[i] = pkattno;
atttypids[i] = attnumTypeId(pkrel, pkattno);
opclasses[i] = indclass->values[i];
*attnamelist = lappend(*attnamelist,
makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno)))));
}
ReleaseSysCache(indexTuple);
return i;
}
/*
* transformFkeyCheckAttrs -
*
* Make sure that the attributes of a referenced table belong to a unique
* (or primary key) constraint. Return the OID of the index supporting
* the constraint, as well as the opclasses associated with the index
* columns.
*/
static Oid
transformFkeyCheckAttrs(Relation pkrel,
int numattrs, int16 *attnums,
Oid *opclasses) /* output parameter */
{
Oid indexoid = InvalidOid;
bool found = false;
List *indexoidlist;
ListCell *indexoidscan;
/*
* Get the list of index OIDs for the table from the relcache, and look up
* each one in the pg_index syscache, and match unique indexes to the list
* of attnums we are given.
*/
indexoidlist = RelationGetIndexList(pkrel);
foreach(indexoidscan, indexoidlist)
{
HeapTuple indexTuple;
Form_pg_index indexStruct;
int i,
j;
indexoid = lfirst_oid(indexoidscan);
indexTuple = SearchSysCache(INDEXRELID,
ObjectIdGetDatum(indexoid),
0, 0, 0);
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
/*
* Must have the right number of columns; must be unique and not a
* partial index; forget it if there are any expressions, too
*/
if (indexStruct->indnatts == numattrs &&
indexStruct->indisunique &&
heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
heap_attisnull(indexTuple, Anum_pg_index_indexprs))
{
/* Must get indclass the hard way */
Datum indclassDatum;
bool isnull;
oidvector *indclass;
indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
Anum_pg_index_indclass, &isnull);
Assert(!isnull);
indclass = (oidvector *) DatumGetPointer(indclassDatum);
/*
* The given attnum list may match the index columns in any order.
* Check that each list is a subset of the other.
*/
for (i = 0; i < numattrs; i++)
{
found = false;
for (j = 0; j < numattrs; j++)
{
if (attnums[i] == indexStruct->indkey.values[j])
{
found = true;
break;
}
}
if (!found)
break;
}
if (found)
{
for (i = 0; i < numattrs; i++)
{
found = false;
for (j = 0; j < numattrs; j++)
{
if (attnums[j] == indexStruct->indkey.values[i])
{
opclasses[j] = indclass->values[i];
found = true;
break;
}
}
if (!found)
break;
}
}
}
ReleaseSysCache(indexTuple);
if (found)
break;
}
if (!found)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FOREIGN_KEY),
errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
RelationGetRelationName(pkrel))));
list_free(indexoidlist);
return indexoid;
}
/*
* Scan the existing rows in a table to verify they meet a proposed FK
* constraint.
*
* Caller must have opened and locked both relations.
*/
static void
validateForeignKeyConstraint(FkConstraint *fkconstraint,
Relation rel,
Relation pkrel,
Oid constraintOid)
{
HeapScanDesc scan;
HeapTuple tuple;
Trigger trig;
/*
* Build a trigger call structure; we'll need it either way.
*/
MemSet(&trig, 0, sizeof(trig));
trig.tgoid = InvalidOid;
trig.tgname = fkconstraint->constr_name;
trig.tgenabled = TRIGGER_FIRES_ON_ORIGIN;
trig.tgisconstraint = TRUE;
trig.tgconstrrelid = RelationGetRelid(pkrel);
trig.tgconstraint = constraintOid;
trig.tgdeferrable = FALSE;
trig.tginitdeferred = FALSE;
/* we needn't fill in tgargs */
/*
* See if we can do it with a single LEFT JOIN query. A FALSE result
* indicates we must proceed with the fire-the-trigger method.
*/
if (RI_Initial_Check(&trig, rel, pkrel))
return;
/*
* Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
* if that tuple had just been inserted. If any of those fail, it should
* ereport(ERROR) and that's that.
*/
scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
FunctionCallInfoData fcinfo;
TriggerData trigdata;
/*
* Make a call to the trigger function
*
* No parameters are passed, but we do set a context
*/
MemSet(&fcinfo, 0, sizeof(fcinfo));
/*
* We assume RI_FKey_check_ins won't look at flinfo...
*/
trigdata.type = T_TriggerData;
trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
trigdata.tg_relation = rel;
trigdata.tg_trigtuple = tuple;
trigdata.tg_newtuple = NULL;
trigdata.tg_trigger = &trig;
trigdata.tg_trigtuplebuf = scan->rs_cbuf;
trigdata.tg_newtuplebuf = InvalidBuffer;
fcinfo.context = (Node *) &trigdata;
RI_FKey_check_ins(&fcinfo);
}
heap_endscan(scan);
}
static void
CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
Oid constraintOid, bool on_insert)
{
CreateTrigStmt *fk_trigger;
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = fkconstraint->constr_name;
fk_trigger->relation = myRel;
fk_trigger->before = false;
fk_trigger->row = true;
/* Either ON INSERT or ON UPDATE */
if (on_insert)
{
fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
fk_trigger->actions[0] = 'i';
}
else
{
fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd");
fk_trigger->actions[0] = 'u';
}
fk_trigger->actions[1] = '\0';
fk_trigger->isconstraint = true;
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->constrrel = fkconstraint->pktable;
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, constraintOid);
/* Make changes-so-far visible */
CommandCounterIncrement();
}
/*
* Create the triggers that implement an FK constraint.
*/
static void
createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
Oid constraintOid)
{
RangeVar *myRel;
CreateTrigStmt *fk_trigger;
/*
* Reconstruct a RangeVar for my relation (not passed in, unfortunately).
*/
myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
pstrdup(RelationGetRelationName(rel)));
/* Make changes-so-far visible */
CommandCounterIncrement();
/*
* Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
* action for both INSERTs and UPDATEs on the referencing table.
*/
CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, true);
CreateFKCheckTrigger(myRel, fkconstraint, constraintOid, false);
/*
* Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
* DELETE action on the referenced table.
*/
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = fkconstraint->constr_name;
fk_trigger->relation = fkconstraint->pktable;
fk_trigger->before = false;
fk_trigger->row = true;
fk_trigger->actions[0] = 'd';
fk_trigger->actions[1] = '\0';
fk_trigger->isconstraint = true;
fk_trigger->constrrel = myRel;
switch (fkconstraint->fk_del_action)
{
case FKCONSTR_ACTION_NOACTION:
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
break;
case FKCONSTR_ACTION_RESTRICT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
break;
case FKCONSTR_ACTION_CASCADE:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
break;
case FKCONSTR_ACTION_SETNULL:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
break;
case FKCONSTR_ACTION_SETDEFAULT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
break;
default:
elog(ERROR, "unrecognized FK action type: %d",
(int) fkconstraint->fk_del_action);
break;
}
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, constraintOid);
/* Make changes-so-far visible */
CommandCounterIncrement();
/*
* Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
* UPDATE action on the referenced table.
*/
fk_trigger = makeNode(CreateTrigStmt);
fk_trigger->trigname = fkconstraint->constr_name;
fk_trigger->relation = fkconstraint->pktable;
fk_trigger->before = false;
fk_trigger->row = true;
fk_trigger->actions[0] = 'u';
fk_trigger->actions[1] = '\0';
fk_trigger->isconstraint = true;
fk_trigger->constrrel = myRel;
switch (fkconstraint->fk_upd_action)
{
case FKCONSTR_ACTION_NOACTION:
fk_trigger->deferrable = fkconstraint->deferrable;
fk_trigger->initdeferred = fkconstraint->initdeferred;
fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
break;
case FKCONSTR_ACTION_RESTRICT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
break;
case FKCONSTR_ACTION_CASCADE:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
break;
case FKCONSTR_ACTION_SETNULL:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
break;
case FKCONSTR_ACTION_SETDEFAULT:
fk_trigger->deferrable = false;
fk_trigger->initdeferred = false;
fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
break;
default:
elog(ERROR, "unrecognized FK action type: %d",
(int) fkconstraint->fk_upd_action);
break;
}
fk_trigger->args = NIL;
(void) CreateTrigger(fk_trigger, constraintOid);
}
/*
* ALTER TABLE DROP CONSTRAINT
*/
static void
ATPrepDropConstraint(List **wqueue, Relation rel,
bool recurse, AlterTableCmd *cmd)
{
/*
* We don't want errors or noise from child tables, so we have to pass
* down a modified command.
*/
if (recurse)
{
AlterTableCmd *childCmd = copyObject(cmd);
childCmd->subtype = AT_DropConstraintQuietly;
ATSimpleRecursion(wqueue, rel, childCmd, recurse);
}
}
static void
ATExecDropConstraint(Relation rel, const char *constrName,
DropBehavior behavior, bool quiet)
{
int deleted;
deleted = RemoveRelConstraints(rel, constrName, behavior);
if (!quiet)
{
/* If zero constraints deleted, complain */
if (deleted == 0)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("constraint \"%s\" does not exist",
constrName)));
/* Otherwise if more than one constraint deleted, notify */
else if (deleted > 1)
ereport(NOTICE,
(errmsg("multiple constraints named \"%s\" were dropped",
constrName)));
}
}
/*
* ALTER COLUMN TYPE
*/
static void
ATPrepAlterColumnType(List **wqueue,
AlteredTableInfo *tab, Relation rel,
bool recurse, bool recursing,
AlterTableCmd *cmd)
{
char *colName = cmd->name;
TypeName *typename = (TypeName *) cmd->def;
HeapTuple tuple;
Form_pg_attribute attTup;
AttrNumber attnum;
Oid targettype;
int32 targettypmod;
Node *transform;
NewColumnValue *newval;
ParseState *pstate = make_parsestate(NULL);
/* lookup the attribute so we can check inheritance status */
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attTup = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = attTup->attnum;
/* Can't alter a system attribute */
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
/* Don't alter inherited columns */
if (attTup->attinhcount > 0 && !recursing)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("cannot alter inherited column \"%s\"",
colName)));
/* Look up the target type */
targettype = typenameTypeId(NULL, typename);
targettypmod = typenameTypeMod(NULL, typename, targettype);
/* make sure datatype is legal for a column */
CheckAttributeType(colName, targettype);
/*
* Set up an expression to transform the old data value to the new type.
* If a USING option was given, transform and use that expression, else
* just take the old value and try to coerce it. We do this first so that
* type incompatibility can be detected before we waste effort, and
* because we need the expression to be parsed against the original table
* rowtype.
*/
if (cmd->transform)
{
RangeTblEntry *rte;
/* Expression must be able to access vars of old table */
rte = addRangeTableEntryForRelation(pstate,
rel,
NULL,
false,
true);
addRTEtoQuery(pstate, rte, false, true, true);
transform = transformExpr(pstate, cmd->transform);
/* It can't return a set */
if (expression_returns_set(transform))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("transform 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 transform expression")));
if (pstate->p_hasAggs)
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("cannot use aggregate function in transform expression")));
}
else
{
transform = (Node *) makeVar(1, attnum,
attTup->atttypid, attTup->atttypmod,
0);
}
transform = coerce_to_target_type(pstate,
transform, exprType(transform),
targettype, targettypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST);
if (transform == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" cannot be cast to type \"%s\"",
colName, TypeNameToString(typename))));
/*
* Add a work queue item to make ATRewriteTable update the column
* contents.
*/
newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
newval->attnum = attnum;
newval->expr = (Expr *) transform;
tab->newvals = lappend(tab->newvals, newval);
ReleaseSysCache(tuple);
/*
* The recursion case is handled by ATSimpleRecursion. However, if we are
* told not to recurse, there had better not be any child tables; else the
* alter would put them out of step.
*/
if (recurse)
ATSimpleRecursion(wqueue, rel, cmd, recurse);
else if (!recursing &&
find_inheritance_children(RelationGetRelid(rel)) != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
errmsg("type of inherited column \"%s\" must be changed in child tables too",
colName)));
}
static void
ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
const char *colName, TypeName *typename)
{
HeapTuple heapTup;
Form_pg_attribute attTup;
AttrNumber attnum;
HeapTuple typeTuple;
Form_pg_type tform;
Oid targettype;
int32 targettypmod;
Node *defaultexpr;
Relation attrelation;
Relation depRel;
ScanKeyData key[3];
SysScanDesc scan;
HeapTuple depTup;
attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
/* Look up the target column */
heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(heapTup)) /* shouldn't happen */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attTup = (Form_pg_attribute) GETSTRUCT(heapTup);
attnum = attTup->attnum;
/* Check for multiple ALTER TYPE on same column --- can't cope */
if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid ||
attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of column \"%s\" twice",
colName)));
/* Look up the target type (should not fail, since prep found it) */
typeTuple = typenameType(NULL, typename);
tform = (Form_pg_type) GETSTRUCT(typeTuple);
targettype = HeapTupleGetOid(typeTuple);
targettypmod = typenameTypeMod(NULL, typename, targettype);
/*
* If there is a default expression for the column, get it and ensure we
* can coerce it to the new datatype. (We must do this before changing
* the column type, because build_column_default itself will try to
* coerce, and will not issue the error message we want if it fails.)
*
* We remove any implicit coercion steps at the top level of the old
* default expression; this has been agreed to satisfy the principle of
* least surprise. (The conversion to the new column type should act like
* it started from what the user sees as the stored expression, and the
* implicit coercions aren't going to be shown.)
*/
if (attTup->atthasdef)
{
defaultexpr = build_column_default(rel, attnum);
Assert(defaultexpr);
defaultexpr = strip_implicit_coercions(defaultexpr);
defaultexpr = coerce_to_target_type(NULL, /* no UNKNOWN params */
defaultexpr, exprType(defaultexpr),
targettype, targettypmod,
COERCION_ASSIGNMENT,
COERCE_IMPLICIT_CAST);
if (defaultexpr == NULL)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("default for column \"%s\" cannot be cast to type \"%s\"",
colName, TypeNameToString(typename))));
}
else
defaultexpr = NULL;
/*
* Find everything that depends on the column (constraints, indexes, etc),
* and record enough information to let us recreate the objects.
*
* The actual recreation does not happen here, but only after we have
* performed all the individual ALTER TYPE operations. We have to save
* the info before executing ALTER TYPE, though, else the deparser will
* get confused.
*
* There could be multiple entries for the same object, so we must check
* to ensure we process each one only once. Note: we assume that an index
* that implements a constraint will not show a direct dependency on the
* column.
*/
depRel = heap_open(DependRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_refobjsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum((int32) attnum));
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTup = systable_getnext(scan)))
{
Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
ObjectAddress foundObject;
/* We don't expect any PIN dependencies on columns */
if (foundDep->deptype == DEPENDENCY_PIN)
elog(ERROR, "cannot alter type of a pinned column");
foundObject.classId = foundDep->classid;
foundObject.objectId = foundDep->objid;
foundObject.objectSubId = foundDep->objsubid;
switch (getObjectClass(&foundObject))
{
case OCLASS_CLASS:
{
char relKind = get_rel_relkind(foundObject.objectId);
if (relKind == RELKIND_INDEX)
{
Assert(foundObject.objectSubId == 0);
if (!list_member_oid(tab->changedIndexOids, foundObject.objectId))
{
tab->changedIndexOids = lappend_oid(tab->changedIndexOids,
foundObject.objectId);
tab->changedIndexDefs = lappend(tab->changedIndexDefs,
pg_get_indexdef_string(foundObject.objectId));
}
}
else if (relKind == RELKIND_SEQUENCE)
{
/*
* This must be a SERIAL column's sequence. We need
* not do anything to it.
*/
Assert(foundObject.objectSubId == 0);
}
else
{
/* Not expecting any other direct dependencies... */
elog(ERROR, "unexpected object depending on column: %s",
getObjectDescription(&foundObject));
}
break;
}
case OCLASS_CONSTRAINT:
Assert(foundObject.objectSubId == 0);
if (!list_member_oid(tab->changedConstraintOids,
foundObject.objectId))
{
char *defstring = pg_get_constraintdef_string(foundObject.objectId);
/*
* Put NORMAL dependencies at the front of the list and
* AUTO dependencies at the back. This makes sure that
* foreign-key constraints depending on this column will
* be dropped before unique or primary-key constraints of
* the column; which we must have because the FK
* constraints depend on the indexes belonging to the
* unique constraints.
*/
if (foundDep->deptype == DEPENDENCY_NORMAL)
{
tab->changedConstraintOids =
lcons_oid(foundObject.objectId,
tab->changedConstraintOids);
tab->changedConstraintDefs =
lcons(defstring,
tab->changedConstraintDefs);
}
else
{
tab->changedConstraintOids =
lappend_oid(tab->changedConstraintOids,
foundObject.objectId);
tab->changedConstraintDefs =
lappend(tab->changedConstraintDefs,
defstring);
}
}
break;
case OCLASS_REWRITE:
/* XXX someday see if we can cope with revising views */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a view or rule"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject),
colName)));
break;
case OCLASS_DEFAULT:
/*
* Ignore the column's default expression, since we will fix
* it below.
*/
Assert(defaultexpr);
break;
case OCLASS_PROC:
case OCLASS_TYPE:
case OCLASS_CAST:
case OCLASS_CONVERSION:
case OCLASS_LANGUAGE:
case OCLASS_OPERATOR:
case OCLASS_OPCLASS:
case OCLASS_TRIGGER:
case OCLASS_SCHEMA:
/*
* We don't expect any of these sorts of objects to depend on
* a column.
*/
elog(ERROR, "unexpected object depending on column: %s",
getObjectDescription(&foundObject));
break;
default:
elog(ERROR, "unrecognized object class: %u",
foundObject.classId);
}
}
systable_endscan(scan);
/*
* Now scan for dependencies of this column on other things. The only
* thing we should find is the dependency on the column datatype, which we
* want to remove.
*/
ScanKeyInit(&key[0],
Anum_pg_depend_classid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_objid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum((int32) attnum));
scan = systable_beginscan(depRel, DependDependerIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTup = systable_getnext(scan)))
{
Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
if (foundDep->deptype != DEPENDENCY_NORMAL)
elog(ERROR, "found unexpected dependency type '%c'",
foundDep->deptype);
if (foundDep->refclassid != TypeRelationId ||
foundDep->refobjid != attTup->atttypid)
elog(ERROR, "found unexpected dependency for column");
simple_heap_delete(depRel, &depTup->t_self);
}
systable_endscan(scan);
heap_close(depRel, RowExclusiveLock);
/*
* Here we go --- change the recorded column type. (Note heapTup is a
* copy of the syscache entry, so okay to scribble on.)
*/
attTup->atttypid = targettype;
attTup->atttypmod = targettypmod;
attTup->attndims = list_length(typename->arrayBounds);
attTup->attlen = tform->typlen;
attTup->attbyval = tform->typbyval;
attTup->attalign = tform->typalign;
attTup->attstorage = tform->typstorage;
ReleaseSysCache(typeTuple);
simple_heap_update(attrelation, &heapTup->t_self, heapTup);
/* keep system catalog indexes current */
CatalogUpdateIndexes(attrelation, heapTup);
heap_close(attrelation, RowExclusiveLock);
/* Install dependency on new datatype */
add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype);
/*
* Drop any pg_statistic entry for the column, since it's now wrong type
*/
RemoveStatistics(RelationGetRelid(rel), attnum);
/*
* Update the default, if present, by brute force --- remove and re-add
* the default. Probably unsafe to take shortcuts, since the new version
* may well have additional dependencies. (It's okay to do this now,
* rather than after other ALTER TYPE commands, since the default won't
* depend on other column types.)
*/
if (defaultexpr)
{
/* Must make new row visible since it will be updated again */
CommandCounterIncrement();
/*
* We use RESTRICT here for safety, but at present we do not expect
* anything to depend on the default.
*/
RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true);
StoreAttrDefault(rel, attnum, nodeToString(defaultexpr));
}
/* Cleanup */
heap_freetuple(heapTup);
}
/*
* Cleanup after we've finished all the ALTER TYPE operations for a
* particular relation. We have to drop and recreate all the indexes
* and constraints that depend on the altered columns.
*/
static void
ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab)
{
ObjectAddress obj;
ListCell *l;
/*
* Re-parse the index and constraint definitions, and attach them to the
* appropriate work queue entries. We do this before dropping because in
* the case of a FOREIGN KEY constraint, we might not yet have exclusive
* lock on the table the constraint is attached to, and we need to get
* that before dropping. It's safe because the parser won't actually look
* at the catalogs to detect the existing entry.
*/
foreach(l, tab->changedIndexDefs)
ATPostAlterTypeParse((char *) lfirst(l), wqueue);
foreach(l, tab->changedConstraintDefs)
ATPostAlterTypeParse((char *) lfirst(l), wqueue);
/*
* Now we can drop the existing constraints and indexes --- constraints
* first, since some of them might depend on the indexes. In fact, we
* have to delete FOREIGN KEY constraints before UNIQUE constraints, but
* we already ordered the constraint list to ensure that would happen. It
* should be okay to use DROP_RESTRICT here, since nothing else should be
* depending on these objects.
*/
foreach(l, tab->changedConstraintOids)
{
obj.classId = ConstraintRelationId;
obj.objectId = lfirst_oid(l);
obj.objectSubId = 0;
performDeletion(&obj, DROP_RESTRICT);
}
foreach(l, tab->changedIndexOids)
{
obj.classId = RelationRelationId;
obj.objectId = lfirst_oid(l);
obj.objectSubId = 0;
performDeletion(&obj, DROP_RESTRICT);
}
/*
* The objects will get recreated during subsequent passes over the work
* queue.
*/
}
static void
ATPostAlterTypeParse(char *cmd, List **wqueue)
{
List *raw_parsetree_list;
List *querytree_list;
ListCell *list_item;
/*
* We expect that we only have to do raw parsing and parse analysis, not
* any rule rewriting, since these will all be utility statements.
*/
raw_parsetree_list = raw_parser(cmd);
querytree_list = NIL;
foreach(list_item, raw_parsetree_list)
{
Node *parsetree = (Node *) lfirst(list_item);
querytree_list = list_concat(querytree_list,
parse_analyze(parsetree, cmd, NULL, 0));
}
/*
* Attach each generated command to the proper place in the work queue.
* Note this could result in creation of entirely new work-queue entries.
*/
foreach(list_item, querytree_list)
{
Query *query = (Query *) lfirst(list_item);
Relation rel;
AlteredTableInfo *tab;
Assert(IsA(query, Query));
Assert(query->commandType == CMD_UTILITY);
switch (nodeTag(query->utilityStmt))
{
case T_IndexStmt:
{
IndexStmt *stmt = (IndexStmt *) query->utilityStmt;
AlterTableCmd *newcmd;
rel = relation_openrv(stmt->relation, AccessExclusiveLock);
tab = ATGetQueueEntry(wqueue, rel);
newcmd = makeNode(AlterTableCmd);
newcmd->subtype = AT_ReAddIndex;
newcmd->def = (Node *) stmt;
tab->subcmds[AT_PASS_OLD_INDEX] =
lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd);
relation_close(rel, NoLock);
break;
}
case T_AlterTableStmt:
{
AlterTableStmt *stmt = (AlterTableStmt *) query->utilityStmt;
ListCell *lcmd;
rel = relation_openrv(stmt->relation, AccessExclusiveLock);
tab = ATGetQueueEntry(wqueue, rel);
foreach(lcmd, stmt->cmds)
{
AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
switch (cmd->subtype)
{
case AT_AddIndex:
cmd->subtype = AT_ReAddIndex;
tab->subcmds[AT_PASS_OLD_INDEX] =
lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
break;
case AT_AddConstraint:
tab->subcmds[AT_PASS_OLD_CONSTR] =
lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
break;
default:
elog(ERROR, "unexpected statement type: %d",
(int) cmd->subtype);
}
}
relation_close(rel, NoLock);
break;
}
default:
elog(ERROR, "unexpected statement type: %d",
(int) nodeTag(query->utilityStmt));
}
}
}
/*
* ALTER TABLE OWNER
*
* recursing is true if we are recursing from a table to its indexes,
* sequences, or toast table. We don't allow the ownership of those things to
* be changed separately from the parent table. Also, we can skip permission
* checks (this is necessary not just an optimization, else we'd fail to
* handle toast tables properly).
*
* recursing is also true if ALTER TYPE OWNER is calling us to fix up a
* free-standing composite type.
*/
void
ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing)
{
Relation target_rel;
Relation class_rel;
HeapTuple tuple;
Form_pg_class tuple_class;
/*
* Get exclusive lock till end of transaction on the target table. Use
* relation_open so that we can work on indexes and sequences.
*/
target_rel = relation_open(relationOid, AccessExclusiveLock);
/* Get its pg_class tuple, too */
class_rel = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCache(RELOID,
ObjectIdGetDatum(relationOid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relationOid);
tuple_class = (Form_pg_class) GETSTRUCT(tuple);
/* Can we change the ownership of this tuple? */
switch (tuple_class->relkind)
{
case RELKIND_RELATION:
case RELKIND_VIEW:
/* ok to change owner */
break;
case RELKIND_INDEX:
if (!recursing)
{
/*
* Because ALTER INDEX OWNER used to be allowed, and in fact
* is generated by old versions of pg_dump, we give a warning
* and do nothing rather than erroring out. Also, to avoid
* unnecessary chatter while restoring those old dumps, say
* nothing at all if the command would be a no-op anyway.
*/
if (tuple_class->relowner != newOwnerId)
ereport(WARNING,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change owner of index \"%s\"",
NameStr(tuple_class->relname)),
errhint("Change the ownership of the index's table, instead.")));
/* quick hack to exit via the no-op path */
newOwnerId = tuple_class->relowner;
}
break;
case RELKIND_SEQUENCE:
if (!recursing &&
tuple_class->relowner != newOwnerId)
{
/* if it's an owned sequence, disallow changing it by itself */
Oid tableId;
int32 colId;
if (sequenceIsOwned(relationOid, &tableId, &colId))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot change owner of sequence \"%s\"",
NameStr(tuple_class->relname)),
errdetail("Sequence \"%s\" is linked to table \"%s\".",
NameStr(tuple_class->relname),
get_rel_name(tableId))));
}
break;
case RELKIND_TOASTVALUE:
case RELKIND_COMPOSITE_TYPE:
if (recursing)
break;
/* FALL THRU */
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, view, or sequence",
NameStr(tuple_class->relname))));
}
/*
* If the new owner is the same as the existing owner, consider the
* command to have succeeded. This is for dump restoration purposes.
*/
if (tuple_class->relowner != newOwnerId)
{
Datum repl_val[Natts_pg_class];
char repl_null[Natts_pg_class];
char repl_repl[Natts_pg_class];
Acl *newAcl;
Datum aclDatum;
bool isNull;
HeapTuple newtuple;
/* skip permission checks when recursing to index or toast table */
if (!recursing)
{
/* Superusers can always do it */
if (!superuser())
{
Oid namespaceOid = tuple_class->relnamespace;
AclResult aclresult;
/* Otherwise, must be owner of the existing object */
if (!pg_class_ownercheck(relationOid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(target_rel));
/* Must be able to become new owner */
check_is_member_of_role(GetUserId(), newOwnerId);
/* New owner must have CREATE privilege on namespace */
aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId,
ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
get_namespace_name(namespaceOid));
}
}
memset(repl_null, ' ', sizeof(repl_null));
memset(repl_repl, ' ', sizeof(repl_repl));
repl_repl[Anum_pg_class_relowner - 1] = 'r';
repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId);
/*
* Determine the modified ACL for the new owner. This is only
* necessary when the ACL is non-null.
*/
aclDatum = SysCacheGetAttr(RELOID, tuple,
Anum_pg_class_relacl,
&isNull);
if (!isNull)
{
newAcl = aclnewowner(DatumGetAclP(aclDatum),
tuple_class->relowner, newOwnerId);
repl_repl[Anum_pg_class_relacl - 1] = 'r';
repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl);
}
newtuple = heap_modifytuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
simple_heap_update(class_rel, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(class_rel, newtuple);
heap_freetuple(newtuple);
/*
* Update owner dependency reference, if any. A composite type has
* none, because it's tracked for the pg_type entry instead of here;
* indexes don't have their own entries either.
*/
if (tuple_class->relkind != RELKIND_COMPOSITE_TYPE &&
tuple_class->relkind != RELKIND_INDEX)
changeDependencyOnOwner(RelationRelationId, relationOid,
newOwnerId);
/*
* Also change the ownership of the table's rowtype, if it has one
*/
if (tuple_class->relkind != RELKIND_INDEX)
AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId,
tuple_class->relkind == RELKIND_COMPOSITE_TYPE);
/*
* If we are operating on a table, also change the ownership of any
* indexes and sequences that belong to the table, as well as the
* table's toast table (if it has one)
*/
if (tuple_class->relkind == RELKIND_RELATION ||
tuple_class->relkind == RELKIND_TOASTVALUE)
{
List *index_oid_list;
ListCell *i;
/* Find all the indexes belonging to this relation */
index_oid_list = RelationGetIndexList(target_rel);
/* For each index, recursively change its ownership */
foreach(i, index_oid_list)
ATExecChangeOwner(lfirst_oid(i), newOwnerId, true);
list_free(index_oid_list);
}
if (tuple_class->relkind == RELKIND_RELATION)
{
/* If it has a toast table, recurse to change its ownership */
if (tuple_class->reltoastrelid != InvalidOid)
ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId,
true);
/* If it has dependent sequences, recurse to change them too */
change_owner_recurse_to_sequences(relationOid, newOwnerId);
}
}
ReleaseSysCache(tuple);
heap_close(class_rel, RowExclusiveLock);
relation_close(target_rel, NoLock);
}
/*
* change_owner_recurse_to_sequences
*
* Helper function for ATExecChangeOwner. Examines pg_depend searching
* for sequences that are dependent on serial columns, and changes their
* ownership.
*/
static void
change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId)
{
Relation depRel;
SysScanDesc scan;
ScanKeyData key[2];
HeapTuple tup;
/*
* SERIAL sequences are those having an auto dependency on one of the
* table's columns (we don't care *which* column, exactly).
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relationOid));
/* we leave refobjsubid unspecified */
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
Relation seqRel;
/* skip dependencies other than auto dependencies on columns */
if (depForm->refobjsubid == 0 ||
depForm->classid != RelationRelationId ||
depForm->objsubid != 0 ||
depForm->deptype != DEPENDENCY_AUTO)
continue;
/* Use relation_open just in case it's an index */
seqRel = relation_open(depForm->objid, AccessExclusiveLock);
/* skip non-sequence relations */
if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
{
/* No need to keep the lock */
relation_close(seqRel, AccessExclusiveLock);
continue;
}
/* We don't need to close the sequence while we alter it. */
ATExecChangeOwner(depForm->objid, newOwnerId, true);
/* Now we can close it. Keep the lock till end of transaction. */
relation_close(seqRel, NoLock);
}
systable_endscan(scan);
relation_close(depRel, AccessShareLock);
}
/*
* ALTER TABLE CLUSTER ON
*
* The only thing we have to do is to change the indisclustered bits.
*/
static void
ATExecClusterOn(Relation rel, const char *indexName)
{
Oid indexOid;
indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace);
if (!OidIsValid(indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("index \"%s\" for table \"%s\" does not exist",
indexName, RelationGetRelationName(rel))));
/* Check index is valid to cluster on */
check_index_is_clusterable(rel, indexOid, false);
/* And do the work */
mark_index_clustered(rel, indexOid);
}
/*
* ALTER TABLE SET WITHOUT CLUSTER
*
* We have to find any indexes on the table that have indisclustered bit
* set and turn it off.
*/
static void
ATExecDropCluster(Relation rel)
{
mark_index_clustered(rel, InvalidOid);
}
/*
* ALTER TABLE SET TABLESPACE
*/
static void
ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename)
{
Oid tablespaceId;
AclResult aclresult;
/* Check that the tablespace exists */
tablespaceId = get_tablespace_oid(tablespacename);
if (!OidIsValid(tablespaceId))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace \"%s\" does not exist", tablespacename)));
/* Check its permissions */
aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
/* Save info for Phase 3 to do the real work */
if (OidIsValid(tab->newTableSpace))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot have multiple SET TABLESPACE subcommands")));
tab->newTableSpace = tablespaceId;
}
/*
* ALTER TABLE/INDEX SET (...) or RESET (...)
*/
static void
ATExecSetRelOptions(Relation rel, List *defList, bool isReset)
{
Oid relid;
Relation pgclass;
HeapTuple tuple;
HeapTuple newtuple;
Datum datum;
bool isnull;
Datum newOptions;
Datum repl_val[Natts_pg_class];
char repl_null[Natts_pg_class];
char repl_repl[Natts_pg_class];
if (defList == NIL)
return; /* nothing to do */
pgclass = heap_open(RelationRelationId, RowExclusiveLock);
/* Get the old reloptions */
relid = RelationGetRelid(rel);
tuple = SearchSysCache(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", relid);
datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions, &isnull);
/* Generate new proposed reloptions (text array) */
newOptions = transformRelOptions(isnull ? (Datum) 0 : datum,
defList, false, isReset);
/* Validate */
switch (rel->rd_rel->relkind)
{
case RELKIND_RELATION:
case RELKIND_TOASTVALUE:
(void) heap_reloptions(rel->rd_rel->relkind, newOptions, true);
break;
case RELKIND_INDEX:
(void) index_reloptions(rel->rd_am->amoptions, newOptions, true);
break;
default:
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table, index, or TOAST table",
RelationGetRelationName(rel))));
break;
}
/*
* All we need do here is update the pg_class row; the new options will be
* propagated into relcaches during post-commit cache inval.
*/
memset(repl_val, 0, sizeof(repl_val));
memset(repl_null, ' ', sizeof(repl_null));
memset(repl_repl, ' ', sizeof(repl_repl));
if (newOptions != (Datum) 0)
repl_val[Anum_pg_class_reloptions - 1] = newOptions;
else
repl_null[Anum_pg_class_reloptions - 1] = 'n';
repl_repl[Anum_pg_class_reloptions - 1] = 'r';
newtuple = heap_modifytuple(tuple, RelationGetDescr(pgclass),
repl_val, repl_null, repl_repl);
simple_heap_update(pgclass, &newtuple->t_self, newtuple);
CatalogUpdateIndexes(pgclass, newtuple);
heap_freetuple(newtuple);
ReleaseSysCache(tuple);
heap_close(pgclass, RowExclusiveLock);
}
/*
* Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
* rewriting to be done, so we just want to copy the data as fast as possible.
*/
static void
ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
{
Relation rel;
Oid oldTableSpace;
Oid reltoastrelid;
Oid reltoastidxid;
RelFileNode newrnode;
SMgrRelation dstrel;
Relation pg_class;
HeapTuple tuple;
Form_pg_class rd_rel;
/*
* Need lock here in case we are recursing to toast table or index
*/
rel = relation_open(tableOid, AccessExclusiveLock);
/*
* We can never allow moving of shared or nailed-in-cache relations,
* because we can't support changing their reltablespace values.
*/
if (rel->rd_rel->relisshared || rel->rd_isnailed)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move system relation \"%s\"",
RelationGetRelationName(rel))));
/*
* Don't allow moving temp tables of other backends ... their local buffer
* manager is not going to cope.
*/
if (isOtherTempNamespace(RelationGetNamespace(rel)))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move temporary tables of other sessions")));
/*
* No work if no change in tablespace.
*/
oldTableSpace = rel->rd_rel->reltablespace;
if (newTableSpace == oldTableSpace ||
(newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0))
{
relation_close(rel, NoLock);
return;
}
reltoastrelid = rel->rd_rel->reltoastrelid;
reltoastidxid = rel->rd_rel->reltoastidxid;
/* Get a modifiable copy of the relation's pg_class row */
pg_class = heap_open(RelationRelationId, RowExclusiveLock);
tuple = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(tableOid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", tableOid);
rd_rel = (Form_pg_class) GETSTRUCT(tuple);
/* create another storage file. Is it a little ugly ? */
/* NOTE: any conflict in relfilenode value will be caught here */
newrnode = rel->rd_node;
newrnode.spcNode = newTableSpace;
dstrel = smgropen(newrnode);
smgrcreate(dstrel, rel->rd_istemp, false);
/* copy relation data to the new physical file */
copy_relation_data(rel, dstrel);
/* schedule unlinking old physical file */
RelationOpenSmgr(rel);
smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
/*
* Now drop smgr references. The source was already dropped by
* smgrscheduleunlink.
*/
smgrclose(dstrel);
/* update the pg_class row */
rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
simple_heap_update(pg_class, &tuple->t_self, tuple);
CatalogUpdateIndexes(pg_class, tuple);
heap_freetuple(tuple);
heap_close(pg_class, RowExclusiveLock);
relation_close(rel, NoLock);
/* Make sure the reltablespace change is visible */
CommandCounterIncrement();
/* Move associated toast relation and/or index, too */
if (OidIsValid(reltoastrelid))
ATExecSetTableSpace(reltoastrelid, newTableSpace);
if (OidIsValid(reltoastidxid))
ATExecSetTableSpace(reltoastidxid, newTableSpace);
}
/*
* Copy data, block by block
*/
static void
copy_relation_data(Relation rel, SMgrRelation dst)
{
SMgrRelation src;
bool use_wal;
BlockNumber nblocks;
BlockNumber blkno;
char buf[BLCKSZ];
Page page = (Page) buf;
/*
* Since we copy the file directly without looking at the shared buffers,
* we'd better first flush out any pages of the source relation that are
* in shared buffers. We assume no new changes will be made while we are
* holding exclusive lock on the rel.
*/
FlushRelationBuffers(rel);
/*
* We need to log the copied data in WAL iff WAL archiving is enabled AND
* it's not a temp rel.
*/
use_wal = XLogArchivingActive() && !rel->rd_istemp;
nblocks = RelationGetNumberOfBlocks(rel);
/* RelationGetNumberOfBlocks will certainly have opened rd_smgr */
src = rel->rd_smgr;
for (blkno = 0; blkno < nblocks; blkno++)
{
smgrread(src, blkno, buf);
/* XLOG stuff */
if (use_wal)
log_newpage(&dst->smgr_rnode, blkno, page);
/*
* Now write the page. We say isTemp = true even if it's not a temp
* rel, because there's no need for smgr to schedule an fsync for this
* write; we'll do it ourselves below.
*/
smgrextend(dst, blkno, buf, true);
}
/*
* If the rel isn't temp, we must fsync it down to disk before it's safe
* to commit the transaction. (For a temp rel we don't care since the rel
* will be uninteresting after a crash anyway.)
*
* It's obvious that we must do this when not WAL-logging the copy. It's
* less obvious that we have to do it even if we did WAL-log the copied
* pages. The reason is that since we're copying outside shared buffers, a
* CHECKPOINT occurring during the copy has no way to flush the previously
* written data to disk (indeed it won't know the new rel even exists). A
* crash later on would replay WAL from the checkpoint, therefore it
* wouldn't replay our earlier WAL entries. If we do not fsync those pages
* here, they might still not be on disk when the crash occurs.
*/
if (!rel->rd_istemp)
smgrimmedsync(dst);
}
/*
* ALTER TABLE ENABLE/DISABLE TRIGGER
*
* We just pass this off to trigger.c.
*/
static void
ATExecEnableDisableTrigger(Relation rel, char *trigname,
char fires_when, bool skip_system)
{
EnableDisableTrigger(rel, trigname, fires_when, skip_system);
}
/*
* ALTER TABLE ENABLE/DISABLE RULE
*
* We just pass this off to rewriteDefine.c.
*/
static void
ATExecEnableDisableRule(Relation rel, char *trigname,
char fires_when)
{
EnableDisableRule(rel, trigname, fires_when);
}
/*
* ALTER TABLE INHERIT
*
* Add a parent to the child's parents. This verifies that all the columns and
* check constraints of the parent appear in the child and that they have the
* same data types and expressions.
*/
static void
ATExecAddInherit(Relation child_rel, RangeVar *parent)
{
Relation parent_rel,
catalogRelation;
SysScanDesc scan;
ScanKeyData key;
HeapTuple inheritsTuple;
int32 inhseqno;
List *children;
/*
* AccessShareLock on the parent is what's obtained during normal CREATE
* TABLE ... INHERITS ..., so should be enough here.
*/
parent_rel = heap_openrv(parent, AccessShareLock);
/*
* Must be owner of both parent and child -- child was checked by
* ATSimplePermissions call in ATPrepCmd
*/
ATSimplePermissions(parent_rel, false);
/* Permanent rels cannot inherit from temporary ones */
if (!isTempNamespace(RelationGetNamespace(child_rel)) &&
isTempNamespace(RelationGetNamespace(parent_rel)))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot inherit from temporary relation \"%s\"",
RelationGetRelationName(parent_rel))));
/*
* Check for duplicates in the list of parents, and determine the highest
* inhseqno already present; we'll use the next one for the new parent.
* (Note: get RowExclusiveLock because we will write pg_inherits below.)
*
* Note: we do not reject the case where the child already inherits from
* the parent indirectly; CREATE TABLE doesn't reject comparable cases.
*/
catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
ScanKeyInit(&key,
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(child_rel)));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
true, SnapshotNow, 1, &key);
/* inhseqno sequences start at 1 */
inhseqno = 0;
while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
{
Form_pg_inherits inh = (Form_pg_inherits) GETSTRUCT(inheritsTuple);
if (inh->inhparent == RelationGetRelid(parent_rel))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("inherited relation \"%s\" duplicated",
RelationGetRelationName(parent_rel))));
if (inh->inhseqno > inhseqno)
inhseqno = inh->inhseqno;
}
systable_endscan(scan);
/*
* Prevent circularity by seeing if proposed parent inherits from child.
* (In particular, this disallows making a rel inherit from itself.)
*
* This is not completely bulletproof because of race conditions: in
* multi-level inheritance trees, someone else could concurrently
* be making another inheritance link that closes the loop but does
* not join either of the rels we have locked. Preventing that seems
* to require exclusive locks on the entire inheritance tree, which is
* a cure worse than the disease. find_all_inheritors() will cope with
* circularity anyway, so don't sweat it too much.
*/
children = find_all_inheritors(RelationGetRelid(child_rel));
if (list_member_oid(children, RelationGetRelid(parent_rel)))
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("circular inheritance not allowed"),
errdetail("\"%s\" is already a child of \"%s\".",
parent->relname,
RelationGetRelationName(child_rel))));
/* If parent has OIDs then child must have OIDs */
if (parent_rel->rd_rel->relhasoids && !child_rel->rd_rel->relhasoids)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("table \"%s\" without OIDs cannot inherit from table \"%s\" with OIDs",
RelationGetRelationName(child_rel),
RelationGetRelationName(parent_rel))));
/* Match up the columns and bump attinhcount and attislocal */
MergeAttributesIntoExisting(child_rel, parent_rel);
/* Match up the constraints and make sure they're present in child */
MergeConstraintsIntoExisting(child_rel, parent_rel);
/*
* OK, it looks valid. Make the catalog entries that show inheritance.
*/
StoreCatalogInheritance1(RelationGetRelid(child_rel),
RelationGetRelid(parent_rel),
inhseqno + 1,
catalogRelation);
/* Now we're done with pg_inherits */
heap_close(catalogRelation, RowExclusiveLock);
/* keep our lock on the parent relation until commit */
heap_close(parent_rel, NoLock);
}
/*
* Obtain the source-text form of the constraint expression for a check
* constraint, given its pg_constraint tuple
*/
static char *
decompile_conbin(HeapTuple contup, TupleDesc tupdesc)
{
Form_pg_constraint con;
bool isnull;
Datum attr;
Datum expr;
con = (Form_pg_constraint) GETSTRUCT(contup);
attr = heap_getattr(contup, Anum_pg_constraint_conbin, tupdesc, &isnull);
if (isnull)
elog(ERROR, "null conbin for constraint %u", HeapTupleGetOid(contup));
expr = DirectFunctionCall2(pg_get_expr, attr,
ObjectIdGetDatum(con->conrelid));
return DatumGetCString(DirectFunctionCall1(textout, expr));
}
/*
* Check columns in child table match up with columns in parent, and increment
* their attinhcount.
*
* Called by ATExecAddInherit
*
* Currently all parent columns must be found in child. Missing columns are an
* error. One day we might consider creating new columns like CREATE TABLE
* does. However, that is widely unpopular --- in the common use case of
* partitioned tables it's a foot-gun.
*
* The data type must match exactly. If the parent column is NOT NULL then
* the child must be as well. Defaults are not compared, however.
*/
static void
MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel)
{
Relation attrrel;
AttrNumber parent_attno;
int parent_natts;
TupleDesc tupleDesc;
TupleConstr *constr;
HeapTuple tuple;
attrrel = heap_open(AttributeRelationId, RowExclusiveLock);
tupleDesc = RelationGetDescr(parent_rel);
parent_natts = tupleDesc->natts;
constr = tupleDesc->constr;
for (parent_attno = 1; parent_attno <= parent_natts; parent_attno++)
{
Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
char *attributeName = NameStr(attribute->attname);
/* Ignore dropped columns in the parent. */
if (attribute->attisdropped)
continue;
/* Find same column in child (matching on column name). */
tuple = SearchSysCacheCopyAttName(RelationGetRelid(child_rel),
attributeName);
if (HeapTupleIsValid(tuple))
{
/* Check they are same type and typmod */
Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
if (attribute->atttypid != childatt->atttypid ||
attribute->atttypmod != childatt->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table \"%s\" has different type for column \"%s\"",
RelationGetRelationName(child_rel),
attributeName)));
if (attribute->attnotnull && !childatt->attnotnull)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" in child table must be marked NOT NULL",
attributeName)));
/*
* OK, bump the child column's inheritance count. (If we fail
* later on, this change will just roll back.)
*/
childatt->attinhcount++;
simple_heap_update(attrrel, &tuple->t_self, tuple);
CatalogUpdateIndexes(attrrel, tuple);
heap_freetuple(tuple);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table is missing column \"%s\"",
attributeName)));
}
}
heap_close(attrrel, RowExclusiveLock);
}
/*
* Check constraints in child table match up with constraints in parent
*
* Called by ATExecAddInherit
*
* Currently all constraints in parent must be present in the child. One day we
* may consider adding new constraints like CREATE TABLE does. We may also want
* to allow an optional flag on parent table constraints indicating they are
* intended to ONLY apply to the master table, not to the children. That would
* make it possible to ensure no records are mistakenly inserted into the
* master in partitioned tables rather than the appropriate child.
*
* XXX This is O(N^2) which may be an issue with tables with hundreds of
* constraints. As long as tables have more like 10 constraints it shouldn't be
* a problem though. Even 100 constraints ought not be the end of the world.
*/
static void
MergeConstraintsIntoExisting(Relation child_rel, Relation parent_rel)
{
Relation catalogRelation;
TupleDesc tupleDesc;
SysScanDesc scan;
ScanKeyData key;
HeapTuple constraintTuple;
ListCell *elem;
List *constraints;
/* First gather up the child's constraint definitions */
catalogRelation = heap_open(ConstraintRelationId, AccessShareLock);
tupleDesc = RelationGetDescr(catalogRelation);
ScanKeyInit(&key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(child_rel)));
scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId,
true, SnapshotNow, 1, &key);
constraints = NIL;
while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
{
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
if (con->contype != CONSTRAINT_CHECK)
continue;
constraints = lappend(constraints, heap_copytuple(constraintTuple));
}
systable_endscan(scan);
/* Then scan through the parent's constraints looking for matches */
ScanKeyInit(&key,
Anum_pg_constraint_conrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(parent_rel)));
scan = systable_beginscan(catalogRelation, ConstraintRelidIndexId, true,
SnapshotNow, 1, &key);
while (HeapTupleIsValid(constraintTuple = systable_getnext(scan)))
{
Form_pg_constraint parent_con = (Form_pg_constraint) GETSTRUCT(constraintTuple);
bool found = false;
Form_pg_constraint child_con = NULL;
HeapTuple child_contuple = NULL;
if (parent_con->contype != CONSTRAINT_CHECK)
continue;
foreach(elem, constraints)
{
child_contuple = (HeapTuple) lfirst(elem);
child_con = (Form_pg_constraint) GETSTRUCT(child_contuple);
if (strcmp(NameStr(parent_con->conname),
NameStr(child_con->conname)) == 0)
{
found = true;
break;
}
}
if (!found)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("child table is missing constraint \"%s\"",
NameStr(parent_con->conname))));
if (parent_con->condeferrable != child_con->condeferrable ||
parent_con->condeferred != child_con->condeferred ||
strcmp(decompile_conbin(constraintTuple, tupleDesc),
decompile_conbin(child_contuple, tupleDesc)) != 0)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("constraint definition for check constraint \"%s\" does not match",
NameStr(parent_con->conname))));
/*
* TODO: add conislocal,coninhcount to constraints. This is where we
* would have to bump them just like attributes
*/
}
systable_endscan(scan);
heap_close(catalogRelation, AccessShareLock);
}
/*
* ALTER TABLE NO INHERIT
*
* Drop a parent from the child's parents. This just adjusts the attinhcount
* and attislocal of the columns and removes the pg_inherit and pg_depend
* entries.
*
* If attinhcount goes to 0 then attislocal gets set to true. If it goes back
* up attislocal stays true, which means if a child is ever removed from a
* parent then its columns will never be automatically dropped which may
* surprise. But at least we'll never surprise by dropping columns someone
* isn't expecting to be dropped which would actually mean data loss.
*/
static void
ATExecDropInherit(Relation rel, RangeVar *parent)
{
Relation parent_rel;
Relation catalogRelation;
SysScanDesc scan;
ScanKeyData key[3];
HeapTuple inheritsTuple,
attributeTuple,
depTuple;
bool found = false;
/*
* AccessShareLock on the parent is probably enough, seeing that DROP TABLE
* doesn't lock parent tables at all. We need some lock since we'll be
* inspecting the parent's schema.
*/
parent_rel = heap_openrv(parent, AccessShareLock);
/*
* We don't bother to check ownership of the parent table --- ownership
* of the child is presumed enough rights.
*/
/*
* Find and destroy the pg_inherits entry linking the two, or error out
* if there is none.
*/
catalogRelation = heap_open(InheritsRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_inherits_inhrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(catalogRelation, InheritsRelidSeqnoIndexId,
true, SnapshotNow, 1, key);
while (HeapTupleIsValid(inheritsTuple = systable_getnext(scan)))
{
Oid inhparent;
inhparent = ((Form_pg_inherits) GETSTRUCT(inheritsTuple))->inhparent;
if (inhparent == RelationGetRelid(parent_rel))
{
simple_heap_delete(catalogRelation, &inheritsTuple->t_self);
found = true;
break;
}
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
if (!found)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("relation \"%s\" is not a parent of relation \"%s\"",
RelationGetRelationName(parent_rel),
RelationGetRelationName(rel))));
/*
* Search through child columns looking for ones matching parent rel
*/
catalogRelation = heap_open(AttributeRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_attribute_attrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
scan = systable_beginscan(catalogRelation, AttributeRelidNumIndexId,
true, SnapshotNow, 1, key);
while (HeapTupleIsValid(attributeTuple = systable_getnext(scan)))
{
Form_pg_attribute att = (Form_pg_attribute) GETSTRUCT(attributeTuple);
/* Ignore if dropped or not inherited */
if (att->attisdropped)
continue;
if (att->attinhcount <= 0)
continue;
if (SearchSysCacheExistsAttName(RelationGetRelid(parent_rel),
NameStr(att->attname)))
{
/* Decrement inhcount and possibly set islocal to true */
HeapTuple copyTuple = heap_copytuple(attributeTuple);
Form_pg_attribute copy_att = (Form_pg_attribute) GETSTRUCT(copyTuple);
copy_att->attinhcount--;
if (copy_att->attinhcount == 0)
copy_att->attislocal = true;
simple_heap_update(catalogRelation, &copyTuple->t_self, copyTuple);
CatalogUpdateIndexes(catalogRelation, copyTuple);
heap_freetuple(copyTuple);
}
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
/*
* Drop the dependency
*
* There's no convenient way to do this, so go trawling through pg_depend
*/
catalogRelation = heap_open(DependRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
Anum_pg_depend_classid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_objid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
ScanKeyInit(&key[2],
Anum_pg_depend_objsubid,
BTEqualStrategyNumber, F_INT4EQ,
Int32GetDatum(0));
scan = systable_beginscan(catalogRelation, DependDependerIndexId, true,
SnapshotNow, 3, key);
while (HeapTupleIsValid(depTuple = systable_getnext(scan)))
{
Form_pg_depend dep = (Form_pg_depend) GETSTRUCT(depTuple);
if (dep->refclassid == RelationRelationId &&
dep->refobjid == RelationGetRelid(parent_rel) &&
dep->refobjsubid == 0 &&
dep->deptype == DEPENDENCY_NORMAL)
simple_heap_delete(catalogRelation, &depTuple->t_self);
}
systable_endscan(scan);
heap_close(catalogRelation, RowExclusiveLock);
/* keep our lock on the parent relation until commit */
heap_close(parent_rel, NoLock);
}
/*
* Execute ALTER TABLE SET SCHEMA
*
* Note: caller must have checked ownership of the relation already
*/
void
AlterTableNamespace(RangeVar *relation, const char *newschema)
{
Relation rel;
Oid relid;
Oid oldNspOid;
Oid nspOid;
Relation classRel;
rel = heap_openrv(relation, AccessExclusiveLock);
relid = RelationGetRelid(rel);
oldNspOid = RelationGetNamespace(rel);
/* heap_openrv allows TOAST, but we don't want to */
if (rel->rd_rel->relkind == RELKIND_TOASTVALUE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a TOAST relation",
RelationGetRelationName(rel))));
/* if it's an owned sequence, disallow moving it by itself */
if (rel->rd_rel->relkind == RELKIND_SEQUENCE)
{
Oid tableId;
int32 colId;
if (sequenceIsOwned(relid, &tableId, &colId))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move an owned sequence into another schema"),
errdetail("Sequence \"%s\" is linked to table \"%s\".",
RelationGetRelationName(rel),
get_rel_name(tableId))));
}
/* get schema OID and check its permissions */
nspOid = LookupCreationNamespace(newschema);
if (oldNspOid == nspOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" is already in schema \"%s\"",
RelationGetRelationName(rel),
newschema)));
/* disallow renaming into or out of temp schemas */
if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move objects into or out of temporary schemas")));
/* same for TOAST schema */
if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot move objects into or out of TOAST schema")));
/* OK, modify the pg_class row and pg_depend entry */
classRel = heap_open(RelationRelationId, RowExclusiveLock);
AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true);
/* Fix the table's rowtype too */
AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false, false);
/* Fix other dependent stuff */
if (rel->rd_rel->relkind == RELKIND_RELATION)
{
AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid);
AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema);
AlterConstraintNamespaces(relid, oldNspOid, nspOid, false);
}
heap_close(classRel, RowExclusiveLock);
/* close rel, but keep lock until commit */
relation_close(rel, NoLock);
}
/*
* The guts of relocating a relation to another namespace: fix the pg_class
* entry, and the pg_depend entry if any. Caller must already have
* opened and write-locked pg_class.
*/
void
AlterRelationNamespaceInternal(Relation classRel, Oid relOid,
Oid oldNspOid, Oid newNspOid,
bool hasDependEntry)
{
HeapTuple classTup;
Form_pg_class classForm;
classTup = SearchSysCacheCopy(RELOID,
ObjectIdGetDatum(relOid),
0, 0, 0);
if (!HeapTupleIsValid(classTup))
elog(ERROR, "cache lookup failed for relation %u", relOid);
classForm = (Form_pg_class) GETSTRUCT(classTup);
Assert(classForm->relnamespace == oldNspOid);
/* check for duplicate name (more friendly than unique-index failure) */
if (get_relname_relid(NameStr(classForm->relname),
newNspOid) != InvalidOid)
ereport(ERROR,
(errcode(ERRCODE_DUPLICATE_TABLE),
errmsg("relation \"%s\" already exists in schema \"%s\"",
NameStr(classForm->relname),
get_namespace_name(newNspOid))));
/* classTup is a copy, so OK to scribble on */
classForm->relnamespace = newNspOid;
simple_heap_update(classRel, &classTup->t_self, classTup);
CatalogUpdateIndexes(classRel, classTup);
/* Update dependency on schema if caller said so */
if (hasDependEntry &&
changeDependencyFor(RelationRelationId, relOid,
NamespaceRelationId, oldNspOid, newNspOid) != 1)
elog(ERROR, "failed to change schema dependency for relation \"%s\"",
NameStr(classForm->relname));
heap_freetuple(classTup);
}
/*
* Move all indexes for the specified relation to another namespace.
*
* Note: we assume adequate permission checking was done by the caller,
* and that the caller has a suitable lock on the owning relation.
*/
static void
AlterIndexNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid)
{
List *indexList;
ListCell *l;
indexList = RelationGetIndexList(rel);
foreach(l, indexList)
{
Oid indexOid = lfirst_oid(l);
/*
* Note: currently, the index will not have its own dependency on the
* namespace, so we don't need to do changeDependencyFor(). There's no
* rowtype in pg_type, either.
*/
AlterRelationNamespaceInternal(classRel, indexOid,
oldNspOid, newNspOid,
false);
}
list_free(indexList);
}
/*
* Move all SERIAL-column sequences of the specified relation to another
* namespace.
*
* Note: we assume adequate permission checking was done by the caller,
* and that the caller has a suitable lock on the owning relation.
*/
static void
AlterSeqNamespaces(Relation classRel, Relation rel,
Oid oldNspOid, Oid newNspOid, const char *newNspName)
{
Relation depRel;
SysScanDesc scan;
ScanKeyData key[2];
HeapTuple tup;
/*
* SERIAL sequences are those having an auto dependency on one of the
* table's columns (we don't care *which* column, exactly).
*/
depRel = heap_open(DependRelationId, AccessShareLock);
ScanKeyInit(&key[0],
Anum_pg_depend_refclassid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationRelationId));
ScanKeyInit(&key[1],
Anum_pg_depend_refobjid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(RelationGetRelid(rel)));
/* we leave refobjsubid unspecified */
scan = systable_beginscan(depRel, DependReferenceIndexId, true,
SnapshotNow, 2, key);
while (HeapTupleIsValid(tup = systable_getnext(scan)))
{
Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
Relation seqRel;
/* skip dependencies other than auto dependencies on columns */
if (depForm->refobjsubid == 0 ||
depForm->classid != RelationRelationId ||
depForm->objsubid != 0 ||
depForm->deptype != DEPENDENCY_AUTO)
continue;
/* Use relation_open just in case it's an index */
seqRel = relation_open(depForm->objid, AccessExclusiveLock);
/* skip non-sequence relations */
if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
{
/* No need to keep the lock */
relation_close(seqRel, AccessExclusiveLock);
continue;
}
/* Fix the pg_class and pg_depend entries */
AlterRelationNamespaceInternal(classRel, depForm->objid,
oldNspOid, newNspOid,
true);
/*
* Sequences have entries in pg_type. We need to be careful to move
* them to the new namespace, too.
*/
AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype,
newNspOid, false, false);
/* Now we can close it. Keep the lock till end of transaction. */
relation_close(seqRel, NoLock);
}
systable_endscan(scan);
relation_close(depRel, AccessShareLock);
}
/*
* This code supports
* CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
*
* Because we only support this for TEMP tables, it's sufficient to remember
* the state in a backend-local data structure.
*/
/*
* Register a newly-created relation's ON COMMIT action.
*/
void
register_on_commit_action(Oid relid, OnCommitAction action)
{
OnCommitItem *oc;
MemoryContext oldcxt;
/*
* We needn't bother registering the relation unless there is an ON COMMIT
* action we need to take.
*/
if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS)
return;
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
oc = (OnCommitItem *) palloc(sizeof(OnCommitItem));
oc->relid = relid;
oc->oncommit = action;
oc->creating_subid = GetCurrentSubTransactionId();
oc->deleting_subid = InvalidSubTransactionId;
on_commits = lcons(oc, on_commits);
MemoryContextSwitchTo(oldcxt);
}
/*
* Unregister any ON COMMIT action when a relation is deleted.
*
* Actually, we only mark the OnCommitItem entry as to be deleted after commit.
*/
void
remove_on_commit_action(Oid relid)
{
ListCell *l;
foreach(l, on_commits)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(l);
if (oc->relid == relid)
{
oc->deleting_subid = GetCurrentSubTransactionId();
break;
}
}
}
/*
* Perform ON COMMIT actions.
*
* This is invoked just before actually committing, since it's possible
* to encounter errors.
*/
void
PreCommit_on_commit_actions(void)
{
ListCell *l;
List *oids_to_truncate = NIL;
foreach(l, on_commits)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(l);
/* Ignore entry if already dropped in this xact */
if (oc->deleting_subid != InvalidSubTransactionId)
continue;
switch (oc->oncommit)
{
case ONCOMMIT_NOOP:
case ONCOMMIT_PRESERVE_ROWS:
/* Do nothing (there shouldn't be such entries, actually) */
break;
case ONCOMMIT_DELETE_ROWS:
oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
break;
case ONCOMMIT_DROP:
{
ObjectAddress object;
object.classId = RelationRelationId;
object.objectId = oc->relid;
object.objectSubId = 0;
performDeletion(&object, DROP_CASCADE);
/*
* Note that table deletion will call
* remove_on_commit_action, so the entry should get marked
* as deleted.
*/
Assert(oc->deleting_subid != InvalidSubTransactionId);
break;
}
}
}
if (oids_to_truncate != NIL)
{
heap_truncate(oids_to_truncate);
CommandCounterIncrement(); /* XXX needed? */
}
}
/*
* Post-commit or post-abort cleanup for ON COMMIT management.
*
* All we do here is remove no-longer-needed OnCommitItem entries.
*
* During commit, remove entries that were deleted during this transaction;
* during abort, remove those created during this transaction.
*/
void
AtEOXact_on_commit_actions(bool isCommit)
{
ListCell *cur_item;
ListCell *prev_item;
prev_item = NULL;
cur_item = list_head(on_commits);
while (cur_item != NULL)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
if (isCommit ? oc->deleting_subid != InvalidSubTransactionId :
oc->creating_subid != InvalidSubTransactionId)
{
/* cur_item must be removed */
on_commits = list_delete_cell(on_commits, cur_item, prev_item);
pfree(oc);
if (prev_item)
cur_item = lnext(prev_item);
else
cur_item = list_head(on_commits);
}
else
{
/* cur_item must be preserved */
oc->creating_subid = InvalidSubTransactionId;
oc->deleting_subid = InvalidSubTransactionId;
prev_item = cur_item;
cur_item = lnext(prev_item);
}
}
}
/*
* Post-subcommit or post-subabort cleanup for ON COMMIT management.
*
* During subabort, we can immediately remove entries created during this
* subtransaction. During subcommit, just relabel entries marked during
* this subtransaction as being the parent's responsibility.
*/
void
AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid)
{
ListCell *cur_item;
ListCell *prev_item;
prev_item = NULL;
cur_item = list_head(on_commits);
while (cur_item != NULL)
{
OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
if (!isCommit && oc->creating_subid == mySubid)
{
/* cur_item must be removed */
on_commits = list_delete_cell(on_commits, cur_item, prev_item);
pfree(oc);
if (prev_item)
cur_item = lnext(prev_item);
else
cur_item = list_head(on_commits);
}
else
{
/* cur_item must be preserved */
if (oc->creating_subid == mySubid)
oc->creating_subid = parentSubid;
if (oc->deleting_subid == mySubid)
oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId;
prev_item = cur_item;
cur_item = lnext(prev_item);
}
}
}
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