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Add a RESTART (without parameter) option to ALTER SEQUENCE, allowing a

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sequence to be reset to its original starting value.  This requires adding the
original start value to the set of parameters (columns) of a sequence object,
which is a user-visible change with potential compatibility implications;
it also forces initdb.

Also add hopefully-SQL-compatible RESTART/CONTINUE IDENTITY options to
TRUNCATE TABLE.  RESTART IDENTITY executes ALTER SEQUENCE RESTART for all
sequences "owned by" any of the truncated relations.  CONTINUE IDENTITY is
a no-op option.

Zoltan Boszormenyi
This commit is contained in:
Tom Lane
2008-05-16 23:36:05 +00:00
parent 8a2f5d221b
commit 10a3471bed
18 changed files with 513 additions and 106 deletions
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57
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.253 2008/05/12 00:00:48 alvherre Exp $
* $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.254 2008/05/16 23:36:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -37,6 +37,7 @@
#include "catalog/toasting.h"
#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "commands/trigger.h"
@ -531,6 +532,7 @@ ExecuteTruncate(TruncateStmt *stmt)
{
List *rels = NIL;
List *relids = NIL;
List *seq_relids = NIL;
EState *estate;
ResultRelInfo *resultRelInfos;
ResultRelInfo *resultRelInfo;
@ -596,6 +598,40 @@ ExecuteTruncate(TruncateStmt *stmt)
heap_truncate_check_FKs(rels, false);
#endif
/*
* If we are asked to restart sequences, find all the sequences,
* lock them (we only need AccessShareLock because that's all that
* ALTER SEQUENCE takes), and check permissions. We want to do this
* early since it's pointless to do all the truncation work only to fail
* on sequence permissions.
*/
if (stmt->restart_seqs)
{
foreach(cell, rels)
{
Relation rel = (Relation) lfirst(cell);
List *seqlist = getOwnedSequences(RelationGetRelid(rel));
ListCell *seqcell;
foreach(seqcell, seqlist)
{
Oid seq_relid = lfirst_oid(seqcell);
Relation seq_rel;
seq_rel = relation_open(seq_relid, AccessShareLock);
/* This check must match AlterSequence! */
if (!pg_class_ownercheck(seq_relid, GetUserId()))
aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
RelationGetRelationName(seq_rel));
seq_relids = lappend_oid(seq_relids, seq_relid);
relation_close(seq_rel, NoLock);
}
}
}
/* Prepare to catch AFTER triggers. */
AfterTriggerBeginQuery();
@ -694,6 +730,25 @@ ExecuteTruncate(TruncateStmt *stmt)
heap_close(rel, NoLock);
}
/*
* Lastly, restart any owned sequences if we were asked to. This is done
* last because it's nontransactional: restarts will not roll back if
* we abort later. Hence it's important to postpone them as long as
* possible. (This is also a big reason why we locked and
* permission-checked the sequences beforehand.)
*/
if (stmt->restart_seqs)
{
List *options = list_make1(makeDefElem("restart", NULL));
foreach(cell, seq_relids)
{
Oid seq_relid = lfirst_oid(cell);
AlterSequenceInternal(seq_relid, options);
}
}
}
/*