From 9a9825f96ad701f5b4f1f19da22cbdd712557e85 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 6 Sep 2002 00:01:53 +0000
Subject: [PATCH] Remove heap_mark4update from AlterTableCreateToastTable.
This has never been the correct procedure for locking a relation, and the
recently-found ALTER TABLE bug with adding a constraint and a toast table in
the same command shows why it's a bad idea.
---
src/backend/commands/tablecmds.c | 52 +++++++++-----------------------
1 file changed, 15 insertions(+), 37 deletions(-)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3b06c6915b2..7b49ba720aa 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.39 2002/09/04 20:31:15 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.40 2002/09/06 00:01:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -3325,11 +3325,9 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
{
Relation rel;
HeapTuple reltup;
- HeapTupleData classtuple;
TupleDesc tupdesc;
bool shared_relation;
Relation class_rel;
- Buffer buffer;
Oid toast_relid;
Oid toast_idxid;
char toast_relname[NAMEDATALEN];
@@ -3366,42 +3364,14 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
if (shared_relation && IsUnderPostmaster)
elog(ERROR, "Shared relations cannot be toasted after initdb");
- /*
- * lock the pg_class tuple for update (is that really needed?)
- */
- class_rel = heap_openr(RelationRelationName, RowExclusiveLock);
-
- reltup = SearchSysCache(RELOID,
- ObjectIdGetDatum(relOid),
- 0, 0, 0);
- if (!HeapTupleIsValid(reltup))
- elog(ERROR, "ALTER TABLE: relation \"%s\" not found",
- RelationGetRelationName(rel));
- classtuple.t_self = reltup->t_self;
- ReleaseSysCache(reltup);
-
- switch (heap_mark4update(class_rel, &classtuple, &buffer,
- GetCurrentCommandId()))
- {
- case HeapTupleSelfUpdated:
- case HeapTupleMayBeUpdated:
- break;
- default:
- elog(ERROR, "couldn't lock pg_class tuple");
- }
- reltup = heap_copytuple(&classtuple);
- ReleaseBuffer(buffer);
-
/*
* Is it already toasted?
*/
- if (((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid != InvalidOid)
+ if (rel->rd_rel->reltoastrelid != InvalidOid)
{
if (silent)
{
heap_close(rel, NoLock);
- heap_close(class_rel, NoLock);
- heap_freetuple(reltup);
return;
}
@@ -3417,8 +3387,6 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
if (silent)
{
heap_close(rel, NoLock);
- heap_close(class_rel, NoLock);
- heap_freetuple(reltup);
return;
}
@@ -3509,8 +3477,17 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
setRelhasindex(toast_relid, true, true, toast_idxid);
/*
- * Store the toast table's OID in the parent relation's tuple
+ * Store the toast table's OID in the parent relation's pg_class row
*/
+ class_rel = heap_openr(RelationRelationName, RowExclusiveLock);
+
+ reltup = SearchSysCacheCopy(RELOID,
+ ObjectIdGetDatum(relOid),
+ 0, 0, 0);
+ if (!HeapTupleIsValid(reltup))
+ elog(ERROR, "ALTER TABLE: relation \"%s\" not found",
+ RelationGetRelationName(rel));
+
((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
simple_heap_update(class_rel, &reltup->t_self, reltup);
@@ -3520,6 +3497,8 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
heap_freetuple(reltup);
+ heap_close(class_rel, RowExclusiveLock);
+
/*
* Register dependency from the toast table to the master, so that the
* toast table will be deleted if the master is.
@@ -3534,9 +3513,8 @@ AlterTableCreateToastTable(Oid relOid, bool silent)
recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
/*
- * Close relations and make changes visible
+ * Clean up and make changes visible
*/
- heap_close(class_rel, NoLock);
heap_close(rel, NoLock);
CommandCounterIncrement();
--
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