Fix markQueryForLocking() to work correctly in the presence of nested views.

It has been wrong for this case since it was first written for 7.1 :-(
Per report from Pavel Hanák.

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index a9843f0d823db6956935ac2ed16714a2069e4ae7..c0e1ec9d978f4701cd7e999995bff8e287fa840b 100644 (file)
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.147.4.1 2006/05/23 17:09:18 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.147.4.2 2007/03/01 18:50:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -51,7 +51,7 @@ static TargetEntry *process_matched_tle(TargetEntry *src_tle,
                    TargetEntry *prior_tle,
                    const char *attrName);
 static Node *get_assignment_input(Node *node);
-static void markQueryForUpdate(Query *qry, bool skipOldNew);
+static void markQueryForUpdate(Query *qry, Node *jtnode);
 static List *matchLocks(CmdType event, RuleLock *rulelocks,
           int varno, Query *parsetree);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
@@ -765,7 +765,7 @@ ApplyRetrieveRule(Query *parsetree,
        /*
         * Set up the view's referenced tables as if FOR UPDATE.
         */
-       markQueryForUpdate(rule_action, true);
+       markQueryForUpdate(rule_action, (Node *) rule_action->jointree);
    }
 
    return parsetree;
@@ -778,23 +778,19 @@ ApplyRetrieveRule(Query *parsetree,
  * aggregate.  We leave it to the planner to detect that.
  *
  * NB: this must agree with the parser's transformForUpdate() routine.
+ * However, unlike the parser we have to be careful not to mark a view's
+ * OLD and NEW rels for updating.  The best way to handle that seems to be
+ * to scan the jointree to determine which rels are used.
  */
 static void
-markQueryForUpdate(Query *qry, bool skipOldNew)
+markQueryForUpdate(Query *qry, Node *jtnode)
 {
-   Index       rti = 0;
-   ListCell   *l;
-
-   foreach(l, qry->rtable)
+   if (jtnode == NULL)
+       return;
+   if (IsA(jtnode, RangeTblRef))
    {
-       RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
-
-       rti++;
-
-       /* Ignore OLD and NEW entries if we are at top level of view */
-       if (skipOldNew &&
-           (rti == PRS2_OLD_VARNO || rti == PRS2_NEW_VARNO))
-           continue;
+       int         rti = ((RangeTblRef *) jtnode)->rtindex;
+       RangeTblEntry *rte = rt_fetch(rti, qry->rtable);
 
        if (rte->rtekind == RTE_RELATION)
        {
@@ -805,9 +801,27 @@ markQueryForUpdate(Query *qry, bool skipOldNew)
        else if (rte->rtekind == RTE_SUBQUERY)
        {
            /* FOR UPDATE of subquery is propagated to subquery's rels */
-           markQueryForUpdate(rte->subquery, false);
+           markQueryForUpdate(rte->subquery, (Node *) rte->subquery->jointree);
        }
    }
+   else if (IsA(jtnode, FromExpr))
+   {
+       FromExpr   *f = (FromExpr *) jtnode;
+       ListCell   *l;
+
+       foreach(l, f->fromlist)
+           markQueryForUpdate(qry, lfirst(l));
+   }
+   else if (IsA(jtnode, JoinExpr))
+   {
+       JoinExpr   *j = (JoinExpr *) jtnode;
+
+       markQueryForUpdate(qry, j->larg);
+       markQueryForUpdate(qry, j->rarg);
+   }
+   else
+       elog(ERROR, "unrecognized node type: %d",
+            (int) nodeTag(jtnode));
 }