From eca1388629facd9e65d2c7ce405e079ba2bc60c4 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 10 Aug 2008 19:02:33 +0000
Subject: [PATCH] Fix corner-case bug introduced with HOT: if REINDEX TABLE
pg_class (or a REINDEX DATABASE including same) is done before a session has
done any other update on pg_class, the pg_class relcache entry was left with
an incorrect setting of rd_indexattr, because the indexed-attributes set
would be first demanded at a time when we'd forced a partial list of indexes
into the pg_class entry, and it would remain cached after that. This could
result in incorrect decisions about HOT-update safety later in the same
session. In practice, since only pg_class_relname_nsp_index would be missed
out, only ALTER TABLE RENAME and ALTER TABLE SET SCHEMA could trigger a
problem. Per report and test case from Ondrej Jirman.
---
src/backend/catalog/index.c | 8 ++++++--
src/backend/utils/cache/relcache.c | 10 ++++++++--
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 3c50d8c5ed2..f06307a7722 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.300 2008/06/19 00:46:04 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.301 2008/08/10 19:02:33 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -2380,9 +2380,13 @@ reindex_relation(Oid relid, bool toast_too)
* problem.
*/
is_pg_class = (RelationGetRelid(rel) == RelationRelationId);
- doneIndexes = NIL;
+
+ /* Ensure rd_indexattr is valid; see comments for RelationSetIndexList */
+ if (is_pg_class)
+ (void) RelationGetIndexAttrBitmap(rel);
/* Reindex all the indexes. */
+ doneIndexes = NIL;
foreach(indexId, indexIds)
{
Oid indexOid = lfirst_oid(indexId);
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 723e9657d5b..7bfb23aaf08 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.272 2008/05/12 00:00:52 alvherre Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.273 2008/08/10 19:02:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2986,6 +2986,13 @@ insert_ordered_oid(List *list, Oid datum)
* messages. In practice it is only used on pg_class (see REINDEX).
*
* It is up to the caller to make sure the given list is correctly ordered.
+ *
+ * We deliberately do not change rd_indexattr here: even when operating
+ * with a temporary partial index list, HOT-update decisions must be made
+ * correctly with respect to the full index set. It is up to the caller
+ * to ensure that a correct rd_indexattr set has been cached before first
+ * calling RelationSetIndexList; else a subsequent inquiry might cause a
+ * wrong rd_indexattr set to get computed and cached.
*/
void
RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
@@ -3004,7 +3011,6 @@ RelationSetIndexList(Relation relation, List *indexIds, Oid oidIndex)
relation->rd_indexvalid = 2; /* mark list as forced */
/* must flag that we have a forced index list */
need_eoxact_work = true;
- /* we deliberately do not change rd_indexattr */
}
/*
--
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