Improve my initial, rather hacky implementation of joins to append

relations: fix the executor so that we can have an Append plan on the
inside of a nestloop and still pass down outer index keys to index scans
within the Append, then generate such plans as if they were regular
inner indexscans.  This avoids the need to evaluate the outer relation
multiple times.

src/backend/optimizer/util/relnode.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.76 2006/02/03 21:08:49 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.77 2006/02/05 02:59:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,7 +18,6 @@
 #include "optimizer/joininfo.h"
 #include "optimizer/pathnode.h"
 #include "optimizer/plancat.h"
-#include "optimizer/prep.h"
 #include "optimizer/restrictinfo.h"
 #include "optimizer/tlist.h"
 #include "parser/parsetree.h"
@@ -571,144 +570,3 @@ subbuild_joinrel_joinlist(RelOptInfo *joinrel,
 		}
 	}
 }
-
-/*
- * translate_join_rel
- *	  Returns relation entry corresponding to the union of two given rels,
- *	  creating a new relation entry if none already exists.  This is used
- *	  when one of the inputs is an append child relation.  In addition to
- *	  data about the input rels themselves, the corresponding joinrel for
- *	  the append parent relation must be provided, plus the AppendRelInfo
- *	  showing the parent-to-child translation.
- *
- * The reason for having this code, instead of just applying build_join_rel,
- * is that we must have corresponding tlist orderings for all joinrels that
- * are involved in an Append plan.  So we generate the tlist for joinrels
- * involving append child relations by translating the parent joinrel's tlist,
- * rather than examining the input relations directly.  (Another reason for
- * doing it this way is that the base relation attr_needed info in relations
- * being joined to the appendrel doesn't refer to the append child rel, but
- * the append parent, and so couldn't be used directly anyway.)  Otherwise
- * this is exactly like build_join_rel.
- */
-RelOptInfo *
-translate_join_rel(PlannerInfo *root,
-				   RelOptInfo *oldjoinrel,
-				   AppendRelInfo *appinfo,
-				   RelOptInfo *outer_rel,
-				   RelOptInfo *inner_rel,
-				   JoinType jointype,
-				   List **restrictlist_ptr)
-{
-	RelOptInfo *joinrel;
-	Relids		joinrelids;
-	List	   *restrictlist;
-
-	/*
-	 * Construct the Relids set for the translated joinrel, and see if
-	 * we've already built it.
-	 */
-	joinrelids = bms_copy(oldjoinrel->relids);
-	joinrelids = bms_del_member(joinrelids, appinfo->parent_relid);
-	joinrelids = bms_add_member(joinrelids, appinfo->child_relid);
-	joinrel = find_join_rel(root, joinrelids);
-	if (joinrel)
-	{
-		/*
-		 * Yes, so we only need to figure the restrictlist for this particular
-		 * pair of component relations.
-		 */
-		bms_free(joinrelids);
-		if (restrictlist_ptr)
-			*restrictlist_ptr = build_joinrel_restrictlist(root,
-														   joinrel,
-														   outer_rel,
-														   inner_rel,
-														   jointype);
-		return joinrel;
-	}
-
-	/*
-	 * Nope, so make one.
-	 */
-	joinrel = makeNode(RelOptInfo);
-	joinrel->reloptkind = RELOPT_JOINREL;
-	joinrel->relids = joinrelids;
-	joinrel->rows = 0;
-	joinrel->width = 0;
-	joinrel->reltargetlist = NIL;
-	joinrel->pathlist = NIL;
-	joinrel->cheapest_startup_path = NULL;
-	joinrel->cheapest_total_path = NULL;
-	joinrel->cheapest_unique_path = NULL;
-	joinrel->relid = 0;			/* indicates not a baserel */
-	joinrel->rtekind = RTE_JOIN;
-	joinrel->min_attr = 0;
-	joinrel->max_attr = 0;
-	joinrel->attr_needed = NULL;
-	joinrel->attr_widths = NULL;
-	joinrel->indexlist = NIL;
-	joinrel->pages = 0;
-	joinrel->tuples = 0;
-	joinrel->subplan = NULL;
-	joinrel->baserestrictinfo = NIL;
-	joinrel->baserestrictcost.startup = 0;
-	joinrel->baserestrictcost.per_tuple = 0;
-	joinrel->joininfo = NIL;
-	joinrel->index_outer_relids = NULL;
-	joinrel->index_inner_paths = NIL;
-
-	/*
-	 * Make the tlist by translating oldjoinrel's tlist, to ensure they
-	 * are in compatible orders.  Since we don't call build_joinrel_tlist,
-	 * we need another way to set the rel width; for the moment, just
-	 * assume it is the same as oldjoinrel.  (The correct value may well be
-	 * less, but it's not clear it's worth the trouble to get it right.)
-	 */
-	joinrel->reltargetlist = (List *)
-		adjust_appendrel_attrs((Node *) oldjoinrel->reltargetlist,
-							   appinfo);
-	joinrel->width = oldjoinrel->width;
-
-	/*
-	 * Construct restrict and join clause lists for the new joinrel. (The
-	 * caller might or might not need the restrictlist, but I need it anyway
-	 * for set_joinrel_size_estimates().)
-	 */
-	restrictlist = build_joinrel_restrictlist(root,
-											  joinrel,
-											  outer_rel,
-											  inner_rel,
-											  jointype);
-	if (restrictlist_ptr)
-		*restrictlist_ptr = restrictlist;
-	build_joinrel_joinlist(joinrel, outer_rel, inner_rel);
-
-	/*
-	 * Set estimates of the joinrel's size.
-	 */
-	set_joinrel_size_estimates(root, joinrel, outer_rel, inner_rel,
-							   jointype, restrictlist);
-
-	/*
-	 * Add the joinrel to the query's joinrel list, and store it into the
-	 * auxiliary hashtable if there is one.  NB: GEQO requires us to append
-	 * the new joinrel to the end of the list!
-	 */
-	root->join_rel_list = lappend(root->join_rel_list, joinrel);
-
-	if (root->join_rel_hash)
-	{
-		JoinHashEntry *hentry;
-		bool		found;
-
-		hentry = (JoinHashEntry *) hash_search(root->join_rel_hash,
-											   &(joinrel->relids),
-											   HASH_ENTER,
-											   &found);
-		Assert(!found);
-		hentry->join_rel = joinrel;
-	}
-
-	return joinrel;
-}