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 ...

diff --git a/src/backend/rewrite/rewriteDefine.c b/src/backend/rewrite/rewriteDefine.c
index 8444bd9138423c985097d50837ba4087c393507a..da0d84ad9d5eda303e18bfe91e94b8973afb0d49 100644 (file)
--- 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);
 }