Handle PlaceHolderVar case in replace_varno_walker

This commit also retires sje_walker.  This increases the generalty of replacing
varno in the parse tree and simplifies the code.

Discussion: https://postgr.es/m/18187-831da249cbd2ff8e%40postgresql.org
Author: Richard Guo
Reviewed-by: Andrei Lepikhov

diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c
index b9be19a687f5013511d9d273be83f151f519b627..00404a8beb0c57a9f5c22e691a4f19bd833b0fcc 100644 (file)
--- a/src/backend/optimizer/plan/analyzejoins.c
+++ b/src/backend/optimizer/plan/analyzejoins.c
@@ -1456,7 +1456,16 @@ replace_varno_walker(Node *node, ReplaceVarnoContext *ctx)
        }
        return false;
    }
-   if (IsA(node, RestrictInfo))
+   else if (IsA(node, PlaceHolderVar))
+   {
+       PlaceHolderVar *phv = (PlaceHolderVar *) node;
+
+       phv->phrels = replace_relid(phv->phrels, ctx->from, ctx->to);
+       phv->phnullingrels = replace_relid(phv->phnullingrels, ctx->from, ctx->to);
+
+       /* fall through to recurse into the placeholder's expression */
+   }
+   else if (IsA(node, RestrictInfo))
    {
        RestrictInfo *rinfo = (RestrictInfo *) node;
        int         relid = -1;
@@ -1641,26 +1650,6 @@ update_eclasses(EquivalenceClass *ec, int from, int to)
    ec->ec_relids = replace_relid(ec->ec_relids, from, to);
 }
 
-static bool
-sje_walker(Node *node, ReplaceVarnoContext *ctx)
-{
-   if (node == NULL)
-       return false;
-
-   if (IsA(node, Var))
-   {
-       Var        *var = (Var *) node;
-
-       if (var->varno == ctx->from)
-       {
-           var->varno = ctx->to;
-           var->varnosyn = ctx->to;
-       }
-       return false;
-   }
-   return expression_tree_walker(node, sje_walker, (void *) ctx);
-}
-
 /*
  * Remove a relation after we have proven that it participates only in an
  * unneeded unique self join.
@@ -1868,7 +1857,8 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark,
    }
 
    /* Replace varno in all the query structures */
-   query_tree_walker(root->parse, sje_walker, &ctx, QTW_EXAMINE_SORTGROUP);
+   query_tree_walker(root->parse, replace_varno_walker, &ctx,
+                     QTW_EXAMINE_SORTGROUP);
 
    /* Replace links in the planner info */
    remove_rel_from_query(root, toRemove, toKeep->relid, NULL, NULL);