Planner failed to be smart about binary-compatible expressions in pathkeys

and hash bucket-size estimation.  Issue has been there awhile but is more
critical in 7.4 because it affects varchar columns.  Per report from
Greg Stark.

diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 059d574c45f19ecba5d5f1574622e623b9951ba4..8f56b6cfbf8c0a5cf5de4702c98cf96170c9d9e3 100644 (file)
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -49,7 +49,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.116 2003/11/29 19:51:50 pgsql Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.117 2003/12/03 17:45:07 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1322,6 +1322,10 @@ estimate_hash_bucketsize(Query *root, Var *var, int nbuckets)
        float4     *numbers;
        int                     nnumbers;
 
+       /* Ignore any binary-compatible relabeling */
+       if (var && IsA(var, RelabelType))
+               var = (Var *) ((RelabelType *) var)->arg;
+
        /*
         * Lookup info about var's relation and attribute; if none available,
         * return default estimate.

diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index e554e0df8e22b4b73f07a29f92a02e2e3bafa7a8..d6d83f7c761d2697214838c8b51896d10b79c212 100644 (file)
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.54 2003/11/29 19:51:50 pgsql Exp $
+ *       $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.55 2003/12/03 17:45:07 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -25,12 +25,13 @@
 #include "optimizer/tlist.h"
 #include "optimizer/var.h"
 #include "parser/parsetree.h"
+#include "parser/parse_expr.h"
 #include "parser/parse_func.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 
 
-static PathKeyItem *makePathKeyItem(Node *key, Oid sortop);
+static PathKeyItem *makePathKeyItem(Node *key, Oid sortop, bool checkType);
 static List *make_canonical_pathkey(Query *root, PathKeyItem *item);
 static Var *find_indexkey_var(Query *root, RelOptInfo *rel,
                                  AttrNumber varattno);
@@ -41,10 +42,29 @@ static Var *find_indexkey_var(Query *root, RelOptInfo *rel,
  *             create a PathKeyItem node
  */
 static PathKeyItem *
-makePathKeyItem(Node *key, Oid sortop)
+makePathKeyItem(Node *key, Oid sortop, bool checkType)
 {
        PathKeyItem *item = makeNode(PathKeyItem);
 
+       /*
+        * Some callers pass expressions that are not necessarily of the same
+        * type as the sort operator expects as input (for example when dealing
+        * with an index that uses binary-compatible operators).  We must relabel
+        * these with the correct type so that the key expressions will be seen
+        * as equal() to expressions that have been correctly labeled.
+        */
+       if (checkType)
+       {
+               Oid                     lefttype,
+                                       righttype;
+
+               op_input_types(sortop, &lefttype, &righttype);
+               if (exprType(key) != lefttype)
+                       key = (Node *) makeRelabelType((Expr *) key,
+                                                                                  lefttype, -1,
+                                                                                  COERCE_DONTCARE);
+       }
+
        item->key = key;
        item->sortop = sortop;
        return item;
@@ -70,9 +90,11 @@ add_equijoined_keys(Query *root, RestrictInfo *restrictinfo)
 {
        Expr       *clause = restrictinfo->clause;
        PathKeyItem *item1 = makePathKeyItem(get_leftop(clause),
-                                                                                restrictinfo->left_sortop);
+                                                                                restrictinfo->left_sortop,
+                                                                                false);
        PathKeyItem *item2 = makePathKeyItem(get_rightop(clause),
-                                                                                restrictinfo->right_sortop);
+                                                                                restrictinfo->right_sortop,
+                                                                                false);
        List       *newset,
                           *cursetlink;
 
@@ -668,7 +690,7 @@ build_index_pathkeys(Query *root,
                }
 
                /* OK, make a sublist for this sort key */
-               item = makePathKeyItem(indexkey, sortop);
+               item = makePathKeyItem(indexkey, sortop, true);
                cpathkey = make_canonical_pathkey(root, item);
 
                /*
@@ -785,7 +807,8 @@ build_subquery_pathkeys(Query *root, RelOptInfo *rel, Query *subquery)
                                                                                tle->resdom->restypmod,
                                                                                0);
                                        outer_item = makePathKeyItem((Node *) outer_var,
-                                                                                                sub_item->sortop);
+                                                                                                sub_item->sortop,
+                                                                                                true);
                                        /* score = # of mergejoin peers */
                                        score = count_canonical_peers(root, outer_item);
                                        /* +1 if it matches the proper query_pathkeys item */
@@ -893,7 +916,7 @@ make_pathkeys_for_sortclauses(List *sortclauses,
                PathKeyItem *pathkey;
 
                sortkey = get_sortgroupclause_expr(sortcl, tlist);
-               pathkey = makePathKeyItem(sortkey, sortcl->sortop);
+               pathkey = makePathKeyItem(sortkey, sortcl->sortop, true);
 
                /*
                 * The pathkey becomes a one-element sublist, for now;
@@ -937,7 +960,7 @@ cache_mergeclause_pathkeys(Query *root, RestrictInfo *restrictinfo)
        {
                oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(restrictinfo));
                key = get_leftop(restrictinfo->clause);
-               item = makePathKeyItem(key, restrictinfo->left_sortop);
+               item = makePathKeyItem(key, restrictinfo->left_sortop, false);
                restrictinfo->left_pathkey = make_canonical_pathkey(root, item);
                MemoryContextSwitchTo(oldcontext);
        }
@@ -945,7 +968,7 @@ cache_mergeclause_pathkeys(Query *root, RestrictInfo *restrictinfo)
        {
                oldcontext = MemoryContextSwitchTo(GetMemoryChunkContext(restrictinfo));
                key = get_rightop(restrictinfo->clause);
-               item = makePathKeyItem(key, restrictinfo->right_sortop);
+               item = makePathKeyItem(key, restrictinfo->right_sortop, false);
                restrictinfo->right_pathkey = make_canonical_pathkey(root, item);
                MemoryContextSwitchTo(oldcontext);
        }

diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
index 6d4053f608c0e378d6f9cb1779d6337ff67fb435..237cf97e6c70f68c8533b8ed6b46ff0f361605d4 100644 (file)
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.111 2003/11/29 19:52:00 pgsql Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.112 2003/12/03 17:45:09 tgl Exp $
  *
  * NOTES
  *       Eventually, the index information should go through here, too.
@@ -465,6 +465,29 @@ get_opname(Oid opno)
                return NULL;
 }
 
+/*
+ * op_input_types
+ *
+ *             Returns the left and right input datatypes for an operator
+ *             (InvalidOid if not relevant).
+ */
+void
+op_input_types(Oid opno, Oid *lefttype, Oid *righttype)
+{
+       HeapTuple       tp;
+       Form_pg_operator optup;
+
+       tp = SearchSysCache(OPEROID,
+                                               ObjectIdGetDatum(opno),
+                                               0, 0, 0);
+       if (!HeapTupleIsValid(tp))      /* shouldn't happen */
+               elog(ERROR, "cache lookup failed for operator %u", opno);
+       optup = (Form_pg_operator) GETSTRUCT(tp);
+       *lefttype = optup->oprleft;
+       *righttype = optup->oprright;
+       ReleaseSysCache(tp);
+}
+
 /*
  * op_mergejoinable
  *

diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index 0d1fb7288a065bcb3550594cc29c71589ba944ef..bd02e132d0f3bb7b2ccbc1f45523fb62e7e7042f 100644 (file)
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.85 2003/11/29 22:41:15 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.86 2003/12/03 17:45:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,6 +42,7 @@ extern bool opclass_is_btree(Oid opclass);
 extern bool opclass_is_hash(Oid opclass);
 extern RegProcedure get_opcode(Oid opno);
 extern char *get_opname(Oid opno);
+extern void op_input_types(Oid opno, Oid *lefttype, Oid *righttype);
 extern bool op_mergejoinable(Oid opno, Oid *leftOp, Oid *rightOp);
 extern void op_mergejoin_crossops(Oid opno, Oid *ltop, Oid *gtop,
                                          RegProcedure *ltproc, RegProcedure *gtproc);