From 66661858aedf01d358cb7081a8d5d645821c452c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 14 Jan 2008 02:49:47 +0000
Subject: [PATCH] Use an indexscan not a heapscan to search pg_index in
get_pkey_attnames. Noted while looking for heapscans that might need to start
from block zero.
---
contrib/dblink/dblink.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 92891a03557..e09d6f16f69 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -8,7 +8,7 @@
* Darko Prenosil <Darko.Prenosil@finteh.hr>
* Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
*
- * $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.68 2008/01/03 21:27:59 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/dblink/dblink.c,v 1.69 2008/01/14 02:49:47 tgl Exp $
* Copyright (c) 2001-2008, PostgreSQL Global Development Group
* ALL RIGHTS RESERVED;
*
@@ -38,8 +38,10 @@
#include "fmgr.h"
#include "funcapi.h"
#include "miscadmin.h"
+#include "access/genam.h"
#include "access/heapam.h"
#include "access/tupdesc.h"
+#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
@@ -1662,8 +1664,8 @@ static char **
get_pkey_attnames(Oid relid, int16 *numatts)
{
Relation indexRelation;
- ScanKeyData entry;
- HeapScanDesc scan;
+ ScanKeyData skey;
+ SysScanDesc scan;
HeapTuple indexTuple;
int i;
char **result = NULL;
@@ -1671,6 +1673,9 @@ get_pkey_attnames(Oid relid, int16 *numatts)
TupleDesc tupdesc;
AclResult aclresult;
+ /* initialize numatts to 0 in case no primary key exists */
+ *numatts = 0;
+
/* open relation using relid, check permissions, get tupdesc */
rel = relation_open(relid, AccessShareLock);
@@ -1682,23 +1687,22 @@ get_pkey_attnames(Oid relid, int16 *numatts)
tupdesc = rel->rd_att;
- /* initialize numatts to 0 in case no primary key exists */
- *numatts = 0;
-
- /* use relid to get all related indexes */
+ /* Prepare to scan pg_index for entries having indrelid = this rel. */
indexRelation = heap_open(IndexRelationId, AccessShareLock);
- ScanKeyInit(&entry,
+ ScanKeyInit(&skey,
Anum_pg_index_indrelid,
BTEqualStrategyNumber, F_OIDEQ,
ObjectIdGetDatum(relid));
- scan = heap_beginscan(indexRelation, SnapshotNow, 1, &entry);
- while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
+ scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
+ SnapshotNow, 1, &skey);
+
+ while (HeapTupleIsValid(indexTuple = systable_getnext(scan)))
{
Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
/* we're only interested if it is the primary key */
- if (index->indisprimary == TRUE)
+ if (index->indisprimary)
{
*numatts = index->indnatts;
if (*numatts > 0)
@@ -1711,7 +1715,8 @@ get_pkey_attnames(Oid relid, int16 *numatts)
break;
}
}
- heap_endscan(scan);
+
+ systable_endscan(scan);
heap_close(indexRelation, AccessShareLock);
relation_close(rel, AccessShareLock);
--
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