Fix nasty bug in optimization of multiway joins: optimizer

would sometimes generate a plan that omitted a sort step before merge.

diff --git a/src/backend/optimizer/path/hashutils.c b/src/backend/optimizer/path/hashutils.c
index 78441f041a100da4537fff2d8925cd76137ec62c..f67e4eb8eca87a8fde11b33d82f53e6661d8006f 100644 (file)
--- a/src/backend/optimizer/path/hashutils.c
+++ b/src/backend/optimizer/path/hashutils.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/hashutils.c,v 1.14 1999/02/22 05:26:18 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/hashutils.c,v 1.15 1999/04/03 00:18:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,19 +29,20 @@ static HashInfo *match_hashop_hashinfo(Oid hashop, List *hashinfo_list);
  *   hash operator.
  *
  * 'restrictinfo_list' is the list of restrictinfo nodes
- * 'inner_relid' is the relid of the inner join relation
+ * 'inner_relids' is the list of relids in the inner join relation
+ *   (used to determine whether a join var is inner or outer)
  *
  * Returns the new list of hashinfo nodes.
  *
  */
 List *
 group_clauses_by_hashop(List *restrictinfo_list,
-                       int inner_relid)
+                       Relids inner_relids)
 {
    List       *hashinfo_list = NIL;
-   RestrictInfo *restrictinfo = (RestrictInfo *) NULL;
-   List       *i = NIL;
-   Oid         hashjoinop = 0;
+   RestrictInfo *restrictinfo;
+   List       *i;
+   Oid         hashjoinop;
 
    foreach(i, restrictinfo_list)
    {
@@ -54,23 +55,21 @@ group_clauses_by_hashop(List *restrictinfo_list,
         */
        if (hashjoinop)
        {
-           HashInfo   *xhashinfo = (HashInfo *) NULL;
            Expr       *clause = restrictinfo->clause;
            Var        *leftop = get_leftop(clause);
            Var        *rightop = get_rightop(clause);
-           JoinKey    *joinkey = (JoinKey *) NULL;
+           HashInfo   *xhashinfo;
+           JoinKey    *joinkey;
 
            xhashinfo = match_hashop_hashinfo(hashjoinop, hashinfo_list);
-
-           if (inner_relid == leftop->varno)
+           joinkey = makeNode(JoinKey);
+           if (intMember(leftop->varno, inner_relids))
            {
-               joinkey = makeNode(JoinKey);
                joinkey->outer = rightop;
                joinkey->inner = leftop;
            }
            else
            {
-               joinkey = makeNode(JoinKey);
                joinkey->outer = leftop;
                joinkey->inner = rightop;
            }
@@ -79,16 +78,15 @@ group_clauses_by_hashop(List *restrictinfo_list,
            {
                xhashinfo = makeNode(HashInfo);
                xhashinfo->hashop = hashjoinop;
-
                xhashinfo->jmethod.jmkeys = NIL;
                xhashinfo->jmethod.clauses = NIL;
-
                hashinfo_list = lcons(xhashinfo, hashinfo_list);
            }
 
-           xhashinfo->jmethod.clauses = lcons(clause, xhashinfo->jmethod.clauses);
-
-           xhashinfo->jmethod.jmkeys = lcons(joinkey, xhashinfo->jmethod.jmkeys);
+           xhashinfo->jmethod.clauses = lcons(clause,
+                                              xhashinfo->jmethod.clauses);
+           xhashinfo->jmethod.jmkeys = lcons(joinkey,
+                                             xhashinfo->jmethod.jmkeys);
        }
    }
    return hashinfo_list;

diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c
index 47668a69b81c5c335a5c1899ec2867b03acc4420..5edfed65b0e9039a39a32afcfbebfa2723565c00 100644 (file)
--- a/src/backend/optimizer/path/joinpath.c
+++ b/src/backend/optimizer/path/joinpath.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.32 1999/02/22 05:26:20 momjian Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.33 1999/04/03 00:18:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -97,11 +97,11 @@ update_rels_pathlist_for_joins(Query *root, List *joinrels)
 
        if (_enable_mergejoin_)
            mergeinfo_list = group_clauses_by_order(joinrel->restrictinfo,
-                                      lfirsti(innerrel->relids));
+                                                   innerrel->relids);
 
        if (_enable_hashjoin_)
            hashinfo_list = group_clauses_by_hashop(joinrel->restrictinfo,
-                                       lfirsti(innerrel->relids));
+                                                   innerrel->relids);
 
        /* need to flatten the relids list */
        joinrel->relids = nconc(listCopy(outerrelids),
@@ -173,12 +173,10 @@ best_innerjoin(List *join_paths, Relids outer_relids)
    {
        Path       *path = (Path *) lfirst(join_path);
 
-       if (intMember(lfirsti(path->joinid), outer_relids)
-           && ((cheapest == NULL ||
-                path_is_cheaper((Path *) lfirst(join_path), cheapest))))
-       {
-           cheapest = (Path *) lfirst(join_path);
-       }
+       if (intMember(lfirsti(path->joinid), outer_relids) &&
+           (cheapest == NULL ||
+            path_is_cheaper(path, cheapest)))
+           cheapest = path;
    }
    return cheapest;
 }

diff --git a/src/backend/optimizer/path/mergeutils.c b/src/backend/optimizer/path/mergeutils.c
index 5f5a11bc7874406a13deca1c206cf979ed00bfed..a5bc8d96980f6a6d94419d5a5aaff384eb06baff 100644 (file)
--- a/src/backend/optimizer/path/mergeutils.c
+++ b/src/backend/optimizer/path/mergeutils.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/mergeutils.c,v 1.20 1999/03/01 00:10:32 tgl Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/mergeutils.c,v 1.21 1999/04/03 00:18:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,14 +36,15 @@
  * Something to fix next time...
  *
  * 'restrictinfo_list' is the list of restrictinfo nodes
- * 'inner_relid' is the relid of the inner join relation
+ * 'inner_relids' is the list of relids in the inner join relation
+ *   (used to determine whether a join var is inner or outer)
  *
  * Returns the new list of mergeinfo nodes.
  *
  */
 List *
 group_clauses_by_order(List *restrictinfo_list,
-                      int inner_relid)
+                      Relids inner_relids)
 {
    List       *mergeinfo_list = NIL;
    List       *xrestrictinfo;
@@ -59,26 +60,25 @@ group_clauses_by_order(List *restrictinfo_list,
             * Create a new mergeinfo node and add it to 'mergeinfo_list'
             * if one does not yet exist for this merge ordering.
             */
-           PathOrder   *pathorder;
-           MergeInfo   *xmergeinfo;
            Expr       *clause = restrictinfo->clause;
            Var        *leftop = get_leftop(clause);
            Var        *rightop = get_rightop(clause);
+           PathOrder   *pathorder;
+           MergeInfo   *xmergeinfo;
            JoinKey    *jmkeys;
 
            pathorder = makeNode(PathOrder);
            pathorder->ordtype = MERGE_ORDER;
            pathorder->ord.merge = merge_ordering;
            xmergeinfo = match_order_mergeinfo(pathorder, mergeinfo_list);
-           if (inner_relid == leftop->varno)
+           jmkeys = makeNode(JoinKey);
+           if (intMember(leftop->varno, inner_relids))
            {
-               jmkeys = makeNode(JoinKey);
                jmkeys->outer = rightop;
                jmkeys->inner = leftop;
            }
            else
            {
-               jmkeys = makeNode(JoinKey);
                jmkeys->outer = leftop;
                jmkeys->inner = rightop;
            }
@@ -86,10 +86,8 @@ group_clauses_by_order(List *restrictinfo_list,
            if (xmergeinfo == NULL)
            {
                xmergeinfo = makeNode(MergeInfo);
-
                xmergeinfo->m_ordering = merge_ordering;
-               mergeinfo_list = lcons(xmergeinfo,
-                                      mergeinfo_list);
+               mergeinfo_list = lcons(xmergeinfo, mergeinfo_list);
            }
 
            xmergeinfo->jmethod.clauses = lcons(clause,

diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index dfd2dfa7871ac3c68a85e27e57b5eb2857dbbda6..603efd7e52c57b6aff65244fb659384fc4d5a11e 100644 (file)
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -7,7 +7,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: paths.h,v 1.26 1999/02/22 05:26:52 momjian Exp $
+ * $Id: paths.h,v 1.27 1999/04/03 00:18:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,7 +48,7 @@ extern List *create_or_index_paths(Query *root, RelOptInfo *rel, List *clauses);
  *   routines to deal with hash keys and clauses
  */
 extern List *group_clauses_by_hashop(List *restrictinfo_list,
-                       int inner_relid);
+                                    Relids inner_relids);
 
 /*
  * joinutils.h
@@ -70,9 +70,9 @@ extern List *new_join_pathkeys(List *outer_pathkeys,
  *   routines to deal with merge keys and clauses
  */
 extern List *group_clauses_by_order(List *restrictinfo_list,
-                      int inner_relid);
+                                   Relids inner_relids);
 extern MergeInfo *match_order_mergeinfo(PathOrder *ordering,
-                     List *mergeinfo_list);
+                                       List *mergeinfo_list);
 
 /*
  * joinrels.h