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 8c0e6530dfec3f2b19aafef174c029fa319fb5ce..b63fb4aff39738b73613c5637907873baedad482 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 1.170 2007/02/01 19:10:27 momjian Exp $
+ *   $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.171 2007/03/01 18:50:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -50,8 +50,8 @@ static TargetEntry *process_matched_tle(TargetEntry *src_tle,
 static Node *get_assignment_input(Node *node);
 static void rewriteValuesRTE(RangeTblEntry *rte, Relation target_relation,
                 List *attrnos);
-static void markQueryForLocking(Query *qry, bool forUpdate, bool noWait,
-                   bool skipOldNew);
+static void markQueryForLocking(Query *qry, Node *jtnode,
+                               bool forUpdate, bool noWait);
 static List *matchLocks(CmdType event, RuleLock *rulelocks,
           int varno, Query *parsetree);
 static Query *fireRIRrules(Query *parsetree, List *activeRIRs);
@@ -1122,8 +1122,8 @@ ApplyRetrieveRule(Query *parsetree,
        /*
         * Set up the view's referenced tables as if FOR UPDATE/SHARE.
         */
-       markQueryForLocking(rule_action, rc->forUpdate,
-                           rc->noWait, true);
+       markQueryForLocking(rule_action, (Node *) rule_action->jointree,
+                           rc->forUpdate, rc->noWait);
    }
 
    return parsetree;
@@ -1135,24 +1135,20 @@ ApplyRetrieveRule(Query *parsetree,
  * This may generate an invalid query, eg if some sub-query uses an
  * aggregate.  We leave it to the planner to detect that.
  *
- * NB: this must agree with the parser's transformLocking() routine.
+ * NB: this must agree with the parser's transformLockingClause() 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
-markQueryForLocking(Query *qry, bool forUpdate, bool noWait, bool skipOldNew)
+markQueryForLocking(Query *qry, Node *jtnode, bool forUpdate, bool noWait)
 {
-   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)
        {
@@ -1162,9 +1158,28 @@ markQueryForLocking(Query *qry, bool forUpdate, bool noWait, bool skipOldNew)
        else if (rte->rtekind == RTE_SUBQUERY)
        {
            /* FOR UPDATE/SHARE of subquery is propagated to subquery's rels */
-           markQueryForLocking(rte->subquery, forUpdate, noWait, false);
+           markQueryForLocking(rte->subquery, (Node *) rte->subquery->jointree,
+                               forUpdate, noWait);
        }
    }
+   else if (IsA(jtnode, FromExpr))
+   {
+       FromExpr   *f = (FromExpr *) jtnode;
+       ListCell   *l;
+
+       foreach(l, f->fromlist)
+           markQueryForLocking(qry, lfirst(l), forUpdate, noWait);
+   }
+   else if (IsA(jtnode, JoinExpr))
+   {
+       JoinExpr   *j = (JoinExpr *) jtnode;
+
+       markQueryForLocking(qry, j->larg, forUpdate, noWait);
+       markQueryForLocking(qry, j->rarg, forUpdate, noWait);
+   }
+   else
+       elog(ERROR, "unrecognized node type: %d",
+            (int) nodeTag(jtnode));
 }