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Transaction safe Truncate 

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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39
src/backend/commands/cluster.c
View File

@ -11,7 +11,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.95 2002/11/18 17:12:07 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/cluster.c,v 1.96 2002/11/23 04:05:51 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -20,12 +20,13 @@
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/catname.h"
#include "catalog/namespace.h"
#include "catalog/pg_constraint.h"
#include "commands/cluster.h"
#include "commands/tablecmds.h"
#include "miscadmin.h"
@ -63,7 +64,6 @@ typedef struct
static Oid make_new_heap(Oid OIDOldHeap, const char *NewName);
static void copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex);
static List *get_indexattr_list(Relation OldHeap, Oid OldIndex);
static void recreate_indexattr(Oid OIDOldHeap, List *indexes);
static void swap_relfilenodes(Oid r1, Oid r2);
static void cluster_rel(relToCluster *rv);
@ -92,11 +92,8 @@ static MemoryContext cluster_context = NULL;
void
cluster_rel(relToCluster *rvtc)
{
Oid OIDNewHeap;
Relation OldHeap,
OldIndex;
char NewHeapName[NAMEDATALEN];
ObjectAddress object;
List *indexes;
/* Check for user-requested abort. */
@ -172,6 +169,22 @@ cluster_rel(relToCluster *rvtc)
index_close(OldIndex);
heap_close(OldHeap, NoLock);
/* rebuild_rel does all the dirty work */
rebuild_rel(rvtc->tableOid, rvtc->indexOid, indexes, true);
}
void
rebuild_rel(Oid tableOid, Oid indexOid, List *indexes, bool dataCopy)
{
Oid OIDNewHeap;
char NewHeapName[NAMEDATALEN];
ObjectAddress object;
/*
* If dataCopy is true, we assume that we will be basing the
* copy off an index for cluster operations.
*/
Assert(!dataCopy || indexOid != NULL);
/*
* Create the new heap, using a temporary name in the same namespace
* as the existing table. NOTE: there is some risk of collision with
@ -180,10 +193,9 @@ cluster_rel(relToCluster *rvtc)
* namespace from the old, or we will have problems with the TEMP
* status of temp tables.
*/
snprintf(NewHeapName, NAMEDATALEN, "pg_temp_%u", rvtc->tableOid);
OIDNewHeap = make_new_heap(rvtc->tableOid, NewHeapName);
snprintf(NewHeapName, NAMEDATALEN, "pg_temp_%u", tableOid);
OIDNewHeap = make_new_heap(tableOid, NewHeapName);
/*
* We don't need CommandCounterIncrement() because make_new_heap did
* it.
@ -192,13 +204,14 @@ cluster_rel(relToCluster *rvtc)
/*
* Copy the heap data into the new table in the desired order.
*/
copy_heap_data(OIDNewHeap, rvtc->tableOid, rvtc->indexOid);
if (dataCopy)
copy_heap_data(OIDNewHeap, tableOid, indexOid);
/* To make the new heap's data visible (probably not needed?). */
CommandCounterIncrement();
/* Swap the relfilenodes of the old and new heaps. */
swap_relfilenodes(rvtc->tableOid, OIDNewHeap);
swap_relfilenodes(tableOid, OIDNewHeap);
CommandCounterIncrement();
@ -219,7 +232,7 @@ cluster_rel(relToCluster *rvtc)
* Recreate each index on the relation. We do not need
* CommandCounterIncrement() because recreate_indexattr does it.
*/
recreate_indexattr(rvtc->tableOid, indexes);
recreate_indexattr(tableOid, indexes);
}
/*
@ -322,7 +335,7 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex)
* Get the necessary info about the indexes of the relation and
* return a list of IndexAttrs structures.
*/
static List *
List *
get_indexattr_list(Relation OldHeap, Oid OldIndex)
{
List *indexes = NIL;

29
src/backend/commands/tablecmds.c
View File

@ -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);
}
/*----------

7
src/include/commands/cluster.h
View File

@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* $Id: cluster.h,v 1.16 2002/11/15 03:09:39 momjian Exp $
* $Id: cluster.h,v 1.17 2002/11/23 04:05:52 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -19,4 +19,9 @@
*/
extern void cluster(ClusterStmt *stmt);
extern List *get_indexattr_list(Relation OldHeap, Oid OldIndex);
extern void rebuild_rel(Oid tableOid, Oid indexOid,
List *indexes, bool dataCopy);
#endif /* CLUSTER_H */

14
src/test/regress/expected/truncate.out
View File

@ -10,7 +10,21 @@ SELECT * FROM truncate_a;
2
(2 rows)
-- Roll truncate back
BEGIN;
TRUNCATE truncate_a;
ROLLBACK;
SELECT * FROM truncate_a;
col1
------
1
2
(2 rows)
-- Commit the truncate this time
BEGIN;
TRUNCATE truncate_a;
COMMIT;
SELECT * FROM truncate_a;
col1
------

8
src/test/regress/sql/truncate.sql
View File

@ -3,7 +3,15 @@ CREATE TABLE truncate_a (col1 integer primary key);
INSERT INTO truncate_a VALUES (1);
INSERT INTO truncate_a VALUES (2);
SELECT * FROM truncate_a;
-- Roll truncate back
BEGIN;
TRUNCATE truncate_a;
ROLLBACK;
SELECT * FROM truncate_a;
-- Commit the truncate this time
BEGIN;
TRUNCATE truncate_a;
COMMIT;
SELECT * FROM truncate_a;
-- Test foreign constraint check