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Code review for ALTER TRIGGER RENAME patch: make better use of index,

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don't scribble on tuple returned by table scan.
This commit is contained in:
Tom Lane
2002-04-30 01:24:57 +00:00
parent 857661ba2e
commit 4c25a0655b
2 changed files with 44 additions and 48 deletions
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89
src/backend/commands/trigger.c
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.116 2002/04/27 03:45:02 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.117 2002/04/30 01:24:57 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -514,8 +514,7 @@ RelationRemoveTriggers(Relation rel)
* for name conflict (within rel) * for name conflict (within rel)
* for original trigger (if not arg) * for original trigger (if not arg)
* modify tgname in trigger tuple * modify tgname in trigger tuple
* insert modified trigger in trigger catalog * update row in catalog
* delete original trigger from trigger catalog
*/ */
void void
renametrig(Oid relid, renametrig(Oid relid,
@ -526,8 +525,7 @@ renametrig(Oid relid,
Relation tgrel; Relation tgrel;
HeapTuple tuple; HeapTuple tuple;
SysScanDesc tgscan; SysScanDesc tgscan;
ScanKeyData key; ScanKeyData key[2];
bool found = FALSE;
Relation idescs[Num_pg_trigger_indices]; Relation idescs[Num_pg_trigger_indices];
/* /*
@ -550,70 +548,69 @@ renametrig(Oid relid,
/* /*
* First pass -- look for name conflict * First pass -- look for name conflict
*/ */
ScanKeyEntryInitialize(&key, 0, ScanKeyEntryInitialize(&key[0], 0,
Anum_pg_trigger_tgrelid, Anum_pg_trigger_tgrelid,
F_OIDEQ, F_OIDEQ,
ObjectIdGetDatum(relid)); ObjectIdGetDatum(relid));
ScanKeyEntryInitialize(&key[1], 0,
Anum_pg_trigger_tgname,
F_NAMEEQ,
PointerGetDatum(newname));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true, tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &key); SnapshotNow, 2, key);
while (HeapTupleIsValid(tuple = systable_getnext(tgscan))) if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{ elog(ERROR, "renametrig: trigger %s already defined on relation %s",
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); newname, RelationGetRelationName(targetrel));
if (namestrcmp(&(pg_trigger->tgname), newname) == 0)
elog(ERROR, "renametrig: trigger %s already defined on relation %s",
newname, RelationGetRelationName(targetrel));
}
systable_endscan(tgscan); systable_endscan(tgscan);
/* /*
* Second pass -- look for trigger existing with oldname and update * Second pass -- look for trigger existing with oldname and update
*/ */
ScanKeyEntryInitialize(&key, 0, ScanKeyEntryInitialize(&key[0], 0,
Anum_pg_trigger_tgrelid, Anum_pg_trigger_tgrelid,
F_OIDEQ, F_OIDEQ,
ObjectIdGetDatum(relid)); ObjectIdGetDatum(relid));
ScanKeyEntryInitialize(&key[1], 0,
Anum_pg_trigger_tgname,
F_NAMEEQ,
PointerGetDatum(oldname));
tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true, tgscan = systable_beginscan(tgrel, TriggerRelidNameIndex, true,
SnapshotNow, 1, &key); SnapshotNow, 2, key);
while (HeapTupleIsValid(tuple = systable_getnext(tgscan))) if (HeapTupleIsValid(tuple = systable_getnext(tgscan)))
{ {
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple); /*
* Update pg_trigger tuple with new tgname.
*/
tuple = heap_copytuple(tuple); /* need a modifiable copy */
if (namestrcmp(&(pg_trigger->tgname), oldname) == 0) namestrcpy(&((Form_pg_trigger) GETSTRUCT(tuple))->tgname, newname);
{
/*
* Update pg_trigger tuple with new tgname.
* (Scribbling on tuple is OK because it's a copy...)
*/
namestrcpy(&(pg_trigger->tgname), newname);
simple_heap_update(tgrel, &tuple->t_self, tuple);
/* simple_heap_update(tgrel, &tuple->t_self, tuple);
* keep system catalog indices current
*/
CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
CatalogCloseIndices(Num_pg_trigger_indices, idescs);
/* /*
* Invalidate relation's relcache entry so that other * keep system catalog indices current
* backends (and this one too!) are sent SI message to make them */
* rebuild relcache entries. CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
*/ CatalogIndexInsert(idescs, Num_pg_trigger_indices, tgrel, tuple);
CacheInvalidateRelcache(relid); CatalogCloseIndices(Num_pg_trigger_indices, idescs);
found = TRUE; /*
break; * Invalidate relation's relcache entry so that other backends (and
} * this one too!) are sent SI message to make them rebuild relcache
* entries. (Ideally this should happen automatically...)
*/
CacheInvalidateRelcache(relid);
} }
else
{
elog(ERROR, "renametrig: trigger %s not defined on relation %s",
oldname, RelationGetRelationName(targetrel));
}
systable_endscan(tgscan); systable_endscan(tgscan);
heap_close(tgrel, RowExclusiveLock); heap_close(tgrel, RowExclusiveLock);
if (!found)
elog(ERROR, "renametrig: trigger %s not defined on relation %s",
oldname, RelationGetRelationName(targetrel));
/* /*
* Close rel, but keep exclusive lock! * Close rel, but keep exclusive lock!
*/ */

3
src/include/commands/tablecmds.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* $Id: tablecmds.h,v 1.3 2002/04/26 19:29:47 tgl Exp $ * $Id: tablecmds.h,v 1.4 2002/04/30 01:24:52 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -15,7 +15,6 @@
#define TABLECMDS_H #define TABLECMDS_H
#include "nodes/parsenodes.h" #include "nodes/parsenodes.h"
#include "utils/inval.h"
extern void AlterTableAddColumn(Oid myrelid, bool inherits, extern void AlterTableAddColumn(Oid myrelid, bool inherits,
ColumnDef *colDef); ColumnDef *colDef);