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Transaction safe Truncate

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Rod Taylor
This commit is contained in:
Bruce Momjian
2002-11-23 04:05:52 +00:00
parent a2b4a7071d
commit d46f3de363
5 changed files with 68 additions and 29 deletions
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29
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.55 2002/11/23 03:59:07 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.56 2002/11/23 04:05:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -29,6 +29,7 @@
#include "catalog/pg_opclass.h"
#include "catalog/pg_trigger.h"
#include "catalog/pg_type.h"
#include "commands/cluster.h"
#include "commands/tablecmds.h"
#include "commands/trigger.h"
#include "executor/executor.h"
@ -360,7 +361,7 @@ RemoveRelation(const RangeVar *relation, DropBehavior behavior)
* Removes all the rows from a relation.
*
* Note: This routine only does safety and permissions checks;
* heap_truncate does the actual work.
* rebuild_rel in cluster.c does the actual work.
*/
void
TruncateRelation(const RangeVar *relation)
@ -371,6 +372,7 @@ TruncateRelation(const RangeVar *relation)
Relation fkeyRel;
SysScanDesc fkeyScan;
HeapTuple tuple;
List *indexes;
/* Grab exclusive lock in preparation for truncate */
rel = heap_openrv(relation, AccessExclusiveLock);
@ -399,16 +401,6 @@ TruncateRelation(const RangeVar *relation)
if (!pg_class_ownercheck(relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
/*
* Truncate within a transaction block is dangerous, because if
* the transaction is later rolled back we have no way to undo
* truncation of the relation's physical file. Disallow it except for
* a rel created in the current xact (which would be deleted on abort,
* anyway).
*/
if (!rel->rd_isnew)
PreventTransactionChain((void *) relation, "TRUNCATE TABLE");
/*
* Don't allow truncate on temp tables of other backends ... their
* local buffer manager is not going to cope.
@ -438,7 +430,8 @@ TruncateRelation(const RangeVar *relation)
Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tuple);
if (con->contype == 'f' && con->conrelid != relid)
elog(ERROR, "TRUNCATE cannot be used as table %s references this one via foreign key constraint %s",
elog(ERROR, "TRUNCATE cannot be used as table %s references "
"this one via foreign key constraint %s",
get_rel_name(con->conrelid),
NameStr(con->conname));
}
@ -446,11 +439,17 @@ TruncateRelation(const RangeVar *relation)
systable_endscan(fkeyScan);
heap_close(fkeyRel, AccessShareLock);
/* Save the information of all indexes on the relation. */
indexes = get_indexattr_list(rel, InvalidOid);
/* Keep the lock until transaction commit */
heap_close(rel, NoLock);
/* Do the real work */
heap_truncate(relid);
/*
* Do the real work using the same technique as cluster, but
* without the code copy portion
*/
rebuild_rel(relid, NULL, indexes, false);
}
/*----------