From 39ee0f55d7a88432b3e2b1184daa318f689b5f32 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 12 Sep 2000 20:38:09 +0000
Subject: [PATCH] Fix relation-to-view conversion so that it doesn't try to
convert a plain relation to a view when you create an ON INSERT/UPDATE/DELETE
rule ...
---
src/backend/rewrite/rewriteDefine.c | 68 ++++++++++++++---------------
1 file changed, 33 insertions(+), 35 deletions(-)
diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index 8444bd91384..da0d84ad9d5 100644
--- a/src/backend/rewrite/rewriteDefine.c
+++ b/src/backend/rewrite/rewriteDefine.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.51 2000/09/12 04:49:09 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteDefine.c,v 1.52 2000/09/12 20:38:09 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -200,40 +200,16 @@ DefineQueryRewrite(RuleStmt *stmt)
foreach(l, action)
{
query = (Query *) lfirst(l);
- if (query->resultRelation == 1)
+ if (query->resultRelation == PRS2_OLD_VARNO)
{
elog(ERROR, "rule actions on OLD currently not supported"
"\n\tuse views or triggers instead");
}
- if (query->resultRelation == 2)
+ if (query->resultRelation == PRS2_NEW_VARNO)
{
elog(ERROR, "rule actions on NEW currently not supported"
"\n\tuse triggers instead");
}
-
- if (event_relation->rd_rel->relkind != RELKIND_VIEW)
- {
- HeapScanDesc scanDesc;
- HeapTuple tuple;
- /*
- * A relation is about to become a view.
- * check that the relation is empty because
- * the storage for the relation is going to
- * be deleted.
- */
-
- scanDesc = heap_beginscan(event_relation, 0, SnapshotNow, 0, NULL);
- tuple = heap_getnext(scanDesc, 0);
- if (HeapTupleIsValid(tuple))
- elog(ERROR, "relation %s is not empty. Cannot convert to view", event_obj->relname);
-
- /* don't need heap_freetuple because we never got a valid tuple */
- heap_endscan(scanDesc);
-
-
- RelisBecomingView = true;
- }
-
}
/*
@@ -333,7 +309,6 @@ DefineQueryRewrite(RuleStmt *stmt)
/*
* ... and finally the rule must be named _RETviewname.
*/
-
expected_name = MakeRetrieveViewRuleName(event_obj->relname);
if (strcmp(expected_name, stmt->rulename) != 0)
{
@@ -341,6 +316,29 @@ DefineQueryRewrite(RuleStmt *stmt)
event_obj->relname, expected_name);
}
pfree(expected_name);
+
+ /*
+ * Are we converting a relation to a view?
+ *
+ * If so, check that the relation is empty because the storage
+ * for the relation is going to be deleted.
+ */
+ if (event_relation->rd_rel->relkind != RELKIND_VIEW)
+ {
+ HeapScanDesc scanDesc;
+ HeapTuple tuple;
+
+ scanDesc = heap_beginscan(event_relation, 0, SnapshotNow, 0, NULL);
+ tuple = heap_getnext(scanDesc, 0);
+ if (HeapTupleIsValid(tuple))
+ elog(ERROR, "Relation \"%s\" is not empty. Cannot convert it to view",
+ event_obj->relname);
+
+ /* don't need heap_freetuple because we never got a valid tuple */
+ heap_endscan(scanDesc);
+
+ RelisBecomingView = true;
+ }
}
/*
@@ -363,7 +361,7 @@ DefineQueryRewrite(RuleStmt *stmt)
is_instead, event_attype);
/* discard rule if it's null action and not INSTEAD; it's a no-op */
- if (action != NULL || is_instead)
+ if (action != NIL || is_instead)
{
Relation relationRelation;
HeapTuple tuple;
@@ -382,8 +380,8 @@ DefineQueryRewrite(RuleStmt *stmt)
/*
* Set pg_class 'relhasrules' field TRUE for event relation.
- * Also modify the 'relkind' field to show that the relation is
- * now a view.
+ * If appropriate, also modify the 'relkind' field to show that
+ * the relation is now a view.
*
* Important side effect: an SI notice is broadcast to force all
* backends (including me!) to update relcache entries with the new
@@ -398,8 +396,8 @@ DefineQueryRewrite(RuleStmt *stmt)
*/
relationRelation = heap_openr(RelationRelationName, RowExclusiveLock);
tuple = SearchSysCacheTupleCopy(RELOID,
- ObjectIdGetDatum(ev_relid),
- 0, 0, 0);
+ ObjectIdGetDatum(ev_relid),
+ 0, 0, 0);
Assert(HeapTupleIsValid(tuple));
/* Do the update */
@@ -420,12 +418,12 @@ DefineQueryRewrite(RuleStmt *stmt)
/*
* IF the relation is becoming a view, delete the storage
- * files associated with it.
+ * files associated with it. NB: we had better have AccessExclusiveLock
+ * to do this ...
*/
if (RelisBecomingView)
smgrunlink(DEFAULT_SMGR, event_relation);
-
/* Close rel, but keep lock till commit... */
heap_close(event_relation, NoLock);
}
--
GitLab