mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-10-02 21:16:54 +02:00
429 lines
12 KiB
C
429 lines
12 KiB
C
|
/*-------------------------------------------------------------------------
|
||
|
*
|
||
|
* pg_attrdef.c
|
||
|
* routines to support manipulation of the pg_attrdef relation
|
||
|
*
|
||
|
* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
|
||
|
* Portions Copyright (c) 1994, Regents of the University of California
|
||
|
*
|
||
|
*
|
||
|
* IDENTIFICATION
|
||
|
* src/backend/catalog/pg_attrdef.c
|
||
|
*
|
||
|
*-------------------------------------------------------------------------
|
||
|
*/
|
||
|
#include "postgres.h"
|
||
|
|
||
|
#include "access/genam.h"
|
||
|
#include "access/relation.h"
|
||
|
#include "access/table.h"
|
||
|
#include "catalog/catalog.h"
|
||
|
#include "catalog/dependency.h"
|
||
|
#include "catalog/indexing.h"
|
||
|
#include "catalog/objectaccess.h"
|
||
|
#include "catalog/pg_attrdef.h"
|
||
|
#include "executor/executor.h"
|
||
|
#include "optimizer/optimizer.h"
|
||
|
#include "utils/array.h"
|
||
|
#include "utils/builtins.h"
|
||
|
#include "utils/fmgroids.h"
|
||
|
#include "utils/rel.h"
|
||
|
#include "utils/syscache.h"
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Store a default expression for column attnum of relation rel.
|
||
|
*
|
||
|
* Returns the OID of the new pg_attrdef tuple.
|
||
|
*
|
||
|
* add_column_mode must be true if we are storing the default for a new
|
||
|
* attribute, and false if it's for an already existing attribute. The reason
|
||
|
* for this is that the missing value must never be updated after it is set,
|
||
|
* which can only be when a column is added to the table. Otherwise we would
|
||
|
* in effect be changing existing tuples.
|
||
|
*/
|
||
|
Oid
|
||
|
StoreAttrDefault(Relation rel, AttrNumber attnum,
|
||
|
Node *expr, bool is_internal, bool add_column_mode)
|
||
|
{
|
||
|
char *adbin;
|
||
|
Relation adrel;
|
||
|
HeapTuple tuple;
|
||
|
Datum values[4];
|
||
|
static bool nulls[4] = {false, false, false, false};
|
||
|
Relation attrrel;
|
||
|
HeapTuple atttup;
|
||
|
Form_pg_attribute attStruct;
|
||
|
char attgenerated;
|
||
|
Oid attrdefOid;
|
||
|
ObjectAddress colobject,
|
||
|
defobject;
|
||
|
|
||
|
adrel = table_open(AttrDefaultRelationId, RowExclusiveLock);
|
||
|
|
||
|
/*
|
||
|
* Flatten expression to string form for storage.
|
||
|
*/
|
||
|
adbin = nodeToString(expr);
|
||
|
|
||
|
/*
|
||
|
* Make the pg_attrdef entry.
|
||
|
*/
|
||
|
attrdefOid = GetNewOidWithIndex(adrel, AttrDefaultOidIndexId,
|
||
|
Anum_pg_attrdef_oid);
|
||
|
values[Anum_pg_attrdef_oid - 1] = ObjectIdGetDatum(attrdefOid);
|
||
|
values[Anum_pg_attrdef_adrelid - 1] = RelationGetRelid(rel);
|
||
|
values[Anum_pg_attrdef_adnum - 1] = attnum;
|
||
|
values[Anum_pg_attrdef_adbin - 1] = CStringGetTextDatum(adbin);
|
||
|
|
||
|
tuple = heap_form_tuple(adrel->rd_att, values, nulls);
|
||
|
CatalogTupleInsert(adrel, tuple);
|
||
|
|
||
|
defobject.classId = AttrDefaultRelationId;
|
||
|
defobject.objectId = attrdefOid;
|
||
|
defobject.objectSubId = 0;
|
||
|
|
||
|
table_close(adrel, RowExclusiveLock);
|
||
|
|
||
|
/* now can free some of the stuff allocated above */
|
||
|
pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1]));
|
||
|
heap_freetuple(tuple);
|
||
|
pfree(adbin);
|
||
|
|
||
|
/*
|
||
|
* Update the pg_attribute entry for the column to show that a default
|
||
|
* exists.
|
||
|
*/
|
||
|
attrrel = table_open(AttributeRelationId, RowExclusiveLock);
|
||
|
atttup = SearchSysCacheCopy2(ATTNUM,
|
||
|
ObjectIdGetDatum(RelationGetRelid(rel)),
|
||
|
Int16GetDatum(attnum));
|
||
|
if (!HeapTupleIsValid(atttup))
|
||
|
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
|
||
|
attnum, RelationGetRelid(rel));
|
||
|
attStruct = (Form_pg_attribute) GETSTRUCT(atttup);
|
||
|
attgenerated = attStruct->attgenerated;
|
||
|
if (!attStruct->atthasdef)
|
||
|
{
|
||
|
Form_pg_attribute defAttStruct;
|
||
|
|
||
|
ExprState *exprState;
|
||
|
Expr *expr2 = (Expr *) expr;
|
||
|
EState *estate = NULL;
|
||
|
ExprContext *econtext;
|
||
|
Datum valuesAtt[Natts_pg_attribute];
|
||
|
bool nullsAtt[Natts_pg_attribute];
|
||
|
bool replacesAtt[Natts_pg_attribute];
|
||
|
Datum missingval = (Datum) 0;
|
||
|
bool missingIsNull = true;
|
||
|
|
||
|
MemSet(valuesAtt, 0, sizeof(valuesAtt));
|
||
|
MemSet(nullsAtt, false, sizeof(nullsAtt));
|
||
|
MemSet(replacesAtt, false, sizeof(replacesAtt));
|
||
|
valuesAtt[Anum_pg_attribute_atthasdef - 1] = true;
|
||
|
replacesAtt[Anum_pg_attribute_atthasdef - 1] = true;
|
||
|
|
||
|
if (rel->rd_rel->relkind == RELKIND_RELATION && add_column_mode &&
|
||
|
!attgenerated)
|
||
|
{
|
||
|
expr2 = expression_planner(expr2);
|
||
|
estate = CreateExecutorState();
|
||
|
exprState = ExecPrepareExpr(expr2, estate);
|
||
|
econtext = GetPerTupleExprContext(estate);
|
||
|
|
||
|
missingval = ExecEvalExpr(exprState, econtext,
|
||
|
&missingIsNull);
|
||
|
|
||
|
FreeExecutorState(estate);
|
||
|
|
||
|
defAttStruct = TupleDescAttr(rel->rd_att, attnum - 1);
|
||
|
|
||
|
if (missingIsNull)
|
||
|
{
|
||
|
/* if the default evaluates to NULL, just store a NULL array */
|
||
|
missingval = (Datum) 0;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
/* otherwise make a one-element array of the value */
|
||
|
missingval = PointerGetDatum(construct_array(&missingval,
|
||
|
1,
|
||
|
defAttStruct->atttypid,
|
||
|
defAttStruct->attlen,
|
||
|
defAttStruct->attbyval,
|
||
|
defAttStruct->attalign));
|
||
|
}
|
||
|
|
||
|
valuesAtt[Anum_pg_attribute_atthasmissing - 1] = !missingIsNull;
|
||
|
replacesAtt[Anum_pg_attribute_atthasmissing - 1] = true;
|
||
|
valuesAtt[Anum_pg_attribute_attmissingval - 1] = missingval;
|
||
|
replacesAtt[Anum_pg_attribute_attmissingval - 1] = true;
|
||
|
nullsAtt[Anum_pg_attribute_attmissingval - 1] = missingIsNull;
|
||
|
}
|
||
|
atttup = heap_modify_tuple(atttup, RelationGetDescr(attrrel),
|
||
|
valuesAtt, nullsAtt, replacesAtt);
|
||
|
|
||
|
CatalogTupleUpdate(attrrel, &atttup->t_self, atttup);
|
||
|
|
||
|
if (!missingIsNull)
|
||
|
pfree(DatumGetPointer(missingval));
|
||
|
|
||
|
}
|
||
|
table_close(attrrel, RowExclusiveLock);
|
||
|
heap_freetuple(atttup);
|
||
|
|
||
|
/*
|
||
|
* Make a dependency so that the pg_attrdef entry goes away if the column
|
||
|
* (or whole table) is deleted.
|
||
|
*/
|
||
|
colobject.classId = RelationRelationId;
|
||
|
colobject.objectId = RelationGetRelid(rel);
|
||
|
colobject.objectSubId = attnum;
|
||
|
|
||
|
recordDependencyOn(&defobject, &colobject, DEPENDENCY_AUTO);
|
||
|
|
||
|
/*
|
||
|
* Record dependencies on objects used in the expression, too.
|
||
|
*/
|
||
|
if (attgenerated)
|
||
|
{
|
||
|
/*
|
||
|
* Generated column: Dropping anything that the generation expression
|
||
|
* refers to automatically drops the generated column.
|
||
|
*/
|
||
|
recordDependencyOnSingleRelExpr(&colobject, expr, RelationGetRelid(rel),
|
||
|
DEPENDENCY_AUTO,
|
||
|
DEPENDENCY_AUTO, false);
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
/*
|
||
|
* Normal default: Dropping anything that the default refers to
|
||
|
* requires CASCADE and drops the default only.
|
||
|
*/
|
||
|
recordDependencyOnSingleRelExpr(&defobject, expr, RelationGetRelid(rel),
|
||
|
DEPENDENCY_NORMAL,
|
||
|
DEPENDENCY_NORMAL, false);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Post creation hook for attribute defaults.
|
||
|
*
|
||
|
* XXX. ALTER TABLE ALTER COLUMN SET/DROP DEFAULT is implemented with a
|
||
|
* couple of deletion/creation of the attribute's default entry, so the
|
||
|
* callee should check existence of an older version of this entry if it
|
||
|
* needs to distinguish.
|
||
|
*/
|
||
|
InvokeObjectPostCreateHookArg(AttrDefaultRelationId,
|
||
|
RelationGetRelid(rel), attnum, is_internal);
|
||
|
|
||
|
return attrdefOid;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* RemoveAttrDefault
|
||
|
*
|
||
|
* If the specified relation/attribute has a default, remove it.
|
||
|
* (If no default, raise error if complain is true, else return quietly.)
|
||
|
*/
|
||
|
void
|
||
|
RemoveAttrDefault(Oid relid, AttrNumber attnum,
|
||
|
DropBehavior behavior, bool complain, bool internal)
|
||
|
{
|
||
|
Relation attrdef_rel;
|
||
|
ScanKeyData scankeys[2];
|
||
|
SysScanDesc scan;
|
||
|
HeapTuple tuple;
|
||
|
bool found = false;
|
||
|
|
||
|
attrdef_rel = table_open(AttrDefaultRelationId, RowExclusiveLock);
|
||
|
|
||
|
ScanKeyInit(&scankeys[0],
|
||
|
Anum_pg_attrdef_adrelid,
|
||
|
BTEqualStrategyNumber, F_OIDEQ,
|
||
|
ObjectIdGetDatum(relid));
|
||
|
ScanKeyInit(&scankeys[1],
|
||
|
Anum_pg_attrdef_adnum,
|
||
|
BTEqualStrategyNumber, F_INT2EQ,
|
||
|
Int16GetDatum(attnum));
|
||
|
|
||
|
scan = systable_beginscan(attrdef_rel, AttrDefaultIndexId, true,
|
||
|
NULL, 2, scankeys);
|
||
|
|
||
|
/* There should be at most one matching tuple, but we loop anyway */
|
||
|
while (HeapTupleIsValid(tuple = systable_getnext(scan)))
|
||
|
{
|
||
|
ObjectAddress object;
|
||
|
Form_pg_attrdef attrtuple = (Form_pg_attrdef) GETSTRUCT(tuple);
|
||
|
|
||
|
object.classId = AttrDefaultRelationId;
|
||
|
object.objectId = attrtuple->oid;
|
||
|
object.objectSubId = 0;
|
||
|
|
||
|
performDeletion(&object, behavior,
|
||
|
internal ? PERFORM_DELETION_INTERNAL : 0);
|
||
|
|
||
|
found = true;
|
||
|
}
|
||
|
|
||
|
systable_endscan(scan);
|
||
|
table_close(attrdef_rel, RowExclusiveLock);
|
||
|
|
||
|
if (complain && !found)
|
||
|
elog(ERROR, "could not find attrdef tuple for relation %u attnum %d",
|
||
|
relid, attnum);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* RemoveAttrDefaultById
|
||
|
*
|
||
|
* Remove a pg_attrdef entry specified by OID. This is the guts of
|
||
|
* attribute-default removal. Note it should be called via performDeletion,
|
||
|
* not directly.
|
||
|
*/
|
||
|
void
|
||
|
RemoveAttrDefaultById(Oid attrdefId)
|
||
|
{
|
||
|
Relation attrdef_rel;
|
||
|
Relation attr_rel;
|
||
|
Relation myrel;
|
||
|
ScanKeyData scankeys[1];
|
||
|
SysScanDesc scan;
|
||
|
HeapTuple tuple;
|
||
|
Oid myrelid;
|
||
|
AttrNumber myattnum;
|
||
|
|
||
|
/* Grab an appropriate lock on the pg_attrdef relation */
|
||
|
attrdef_rel = table_open(AttrDefaultRelationId, RowExclusiveLock);
|
||
|
|
||
|
/* Find the pg_attrdef tuple */
|
||
|
ScanKeyInit(&scankeys[0],
|
||
|
Anum_pg_attrdef_oid,
|
||
|
BTEqualStrategyNumber, F_OIDEQ,
|
||
|
ObjectIdGetDatum(attrdefId));
|
||
|
|
||
|
scan = systable_beginscan(attrdef_rel, AttrDefaultOidIndexId, true,
|
||
|
NULL, 1, scankeys);
|
||
|
|
||
|
tuple = systable_getnext(scan);
|
||
|
if (!HeapTupleIsValid(tuple))
|
||
|
elog(ERROR, "could not find tuple for attrdef %u", attrdefId);
|
||
|
|
||
|
myrelid = ((Form_pg_attrdef) GETSTRUCT(tuple))->adrelid;
|
||
|
myattnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
|
||
|
|
||
|
/* Get an exclusive lock on the relation owning the attribute */
|
||
|
myrel = relation_open(myrelid, AccessExclusiveLock);
|
||
|
|
||
|
/* Now we can delete the pg_attrdef row */
|
||
|
CatalogTupleDelete(attrdef_rel, &tuple->t_self);
|
||
|
|
||
|
systable_endscan(scan);
|
||
|
table_close(attrdef_rel, RowExclusiveLock);
|
||
|
|
||
|
/* Fix the pg_attribute row */
|
||
|
attr_rel = table_open(AttributeRelationId, RowExclusiveLock);
|
||
|
|
||
|
tuple = SearchSysCacheCopy2(ATTNUM,
|
||
|
ObjectIdGetDatum(myrelid),
|
||
|
Int16GetDatum(myattnum));
|
||
|
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
|
||
|
elog(ERROR, "cache lookup failed for attribute %d of relation %u",
|
||
|
myattnum, myrelid);
|
||
|
|
||
|
((Form_pg_attribute) GETSTRUCT(tuple))->atthasdef = false;
|
||
|
|
||
|
CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
|
||
|
|
||
|
/*
|
||
|
* Our update of the pg_attribute row will force a relcache rebuild, so
|
||
|
* there's nothing else to do here.
|
||
|
*/
|
||
|
table_close(attr_rel, RowExclusiveLock);
|
||
|
|
||
|
/* Keep lock on attribute's rel until end of xact */
|
||
|
relation_close(myrel, NoLock);
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Get the pg_attrdef OID of the default expression for a column
|
||
|
* identified by relation OID and and column number.
|
||
|
*
|
||
|
* Returns InvalidOid if there is no such pg_attrdef entry.
|
||
|
*/
|
||
|
Oid
|
||
|
GetAttrDefaultOid(Oid relid, AttrNumber attnum)
|
||
|
{
|
||
|
Oid result = InvalidOid;
|
||
|
Relation attrdef;
|
||
|
ScanKeyData keys[2];
|
||
|
SysScanDesc scan;
|
||
|
HeapTuple tup;
|
||
|
|
||
|
attrdef = table_open(AttrDefaultRelationId, AccessShareLock);
|
||
|
ScanKeyInit(&keys[0],
|
||
|
Anum_pg_attrdef_adrelid,
|
||
|
BTEqualStrategyNumber,
|
||
|
F_OIDEQ,
|
||
|
ObjectIdGetDatum(relid));
|
||
|
ScanKeyInit(&keys[1],
|
||
|
Anum_pg_attrdef_adnum,
|
||
|
BTEqualStrategyNumber,
|
||
|
F_INT2EQ,
|
||
|
Int16GetDatum(attnum));
|
||
|
scan = systable_beginscan(attrdef, AttrDefaultIndexId, true,
|
||
|
NULL, 2, keys);
|
||
|
|
||
|
if (HeapTupleIsValid(tup = systable_getnext(scan)))
|
||
|
{
|
||
|
Form_pg_attrdef atdform = (Form_pg_attrdef) GETSTRUCT(tup);
|
||
|
|
||
|
result = atdform->oid;
|
||
|
}
|
||
|
|
||
|
systable_endscan(scan);
|
||
|
table_close(attrdef, AccessShareLock);
|
||
|
|
||
|
return result;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Given a pg_attrdef OID, return the relation OID and column number of
|
||
|
* the owning column (represented as an ObjectAddress for convenience).
|
||
|
*
|
||
|
* Returns InvalidObjectAddress if there is no such pg_attrdef entry.
|
||
|
*/
|
||
|
ObjectAddress
|
||
|
GetAttrDefaultColumnAddress(Oid attrdefoid)
|
||
|
{
|
||
|
ObjectAddress result = InvalidObjectAddress;
|
||
|
Relation attrdef;
|
||
|
ScanKeyData skey[1];
|
||
|
SysScanDesc scan;
|
||
|
HeapTuple tup;
|
||
|
|
||
|
attrdef = table_open(AttrDefaultRelationId, AccessShareLock);
|
||
|
ScanKeyInit(&skey[0],
|
||
|
Anum_pg_attrdef_oid,
|
||
|
BTEqualStrategyNumber, F_OIDEQ,
|
||
|
ObjectIdGetDatum(attrdefoid));
|
||
|
scan = systable_beginscan(attrdef, AttrDefaultOidIndexId, true,
|
||
|
NULL, 1, skey);
|
||
|
|
||
|
if (HeapTupleIsValid(tup = systable_getnext(scan)))
|
||
|
{
|
||
|
Form_pg_attrdef atdform = (Form_pg_attrdef) GETSTRUCT(tup);
|
||
|
|
||
|
result.classId = RelationRelationId;
|
||
|
result.objectId = atdform->adrelid;
|
||
|
result.objectSubId = atdform->adnum;
|
||
|
}
|
||
|
|
||
|
systable_endscan(scan);
|
||
|
table_close(attrdef, AccessShareLock);
|
||
|
|
||
|
return result;
|
||
|
}
|