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Generalize TRUNCATE to support truncating multiple tables in one

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command.  This is useful because we can allow truncation of tables
referenced by foreign keys, so long as the referencing table is
truncated in the same command.

Alvaro Herrera
This commit is contained in:
Tom Lane
2005-01-27 03:19:37 +00:00
parent 4fe201237f
commit f07b9689c9
14 changed files with 398 additions and 180 deletions
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182
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.143 2005/01/24 23:21:57 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.144 2005/01/27 03:17:30 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -525,88 +525,113 @@ RemoveRelation(const RangeVar *relation, DropBehavior behavior)
}
/*
* TruncateRelation
* Removes all the rows from a relation.
* ExecuteTruncate
* Executes a TRUNCATE command.
*
* This is a multi-relation truncate. It first opens and grabs exclusive
* locks on all relations involved, checking permissions and otherwise
* verifying that the relation is OK for truncation. When they are all
* open, it checks foreign key references on them, namely that FK references
* are all internal to the group that's being truncated. Finally all
* relations are truncated and reindexed.
*/
void
TruncateRelation(const RangeVar *relation)
ExecuteTruncate(List *relations)
{
Relation rel;
Oid heap_relid;
Oid toast_relid;
List *rels = NIL;
ListCell *cell;
/* Grab exclusive lock in preparation for truncate */
rel = heap_openrv(relation, AccessExclusiveLock);
/* 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")));
/*
* Don't allow truncate on tables which are referenced by foreign keys
*/
heap_truncate_check_FKs(rel);
/*
* Okay, here we go: 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))
foreach(cell, relations)
{
rel = relation_open(toast_relid, AccessExclusiveLock);
setNewRelfilenode(rel);
heap_close(rel, NoLock);
RangeVar *rv = lfirst(cell);
Relation rel;
/* Grab exclusive lock in preparation for truncate */
rel = heap_openrv(rv, AccessExclusiveLock);
/* 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")));
/* Save it into the list of rels to truncate */
rels = lappend(rels, rel);
}
/*
* Reconstruct the indexes to match, and we're done.
* Check foreign key references.
*/
reindex_relation(heap_relid, true);
heap_truncate_check_FKs(rels, false);
/*
* OK, truncate each table.
*/
foreach(cell, rels)
{
Relation rel = 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);
}
}
/*----------
@ -6013,6 +6038,7 @@ void
PreCommit_on_commit_actions(void)
{
ListCell *l;
List *oids_to_truncate = NIL;
foreach(l, on_commits)
{
@ -6029,8 +6055,7 @@ PreCommit_on_commit_actions(void)
/* Do nothing (there shouldn't be such entries, actually) */
break;
case ONCOMMIT_DELETE_ROWS:
heap_truncate(oc->relid);
CommandCounterIncrement(); /* XXX needed? */
oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
break;
case ONCOMMIT_DROP:
{
@ -6051,6 +6076,11 @@ PreCommit_on_commit_actions(void)
}
}
}
if (oids_to_truncate != NIL)
{
heap_truncate(oids_to_truncate);
CommandCounterIncrement(); /* XXX needed? */
}
}
/*