Restructure planner's handling of inheritance. Rather than processing

inheritance trees on-the-fly, which pretty well constrained us to considering
only one way of planning inheritance, expand inheritance sets during the
planner prep phase, and build a side data structure that can be consulted
later to find which RTEs are members of which inheritance sets.  As proof of
concept, use the data structure to plan joins against inheritance sets more
efficiently: we can now use indexes on the set members in inner-indexscan
joins.  (The generated plans could be improved further, but it'll take some
executor changes.)  This data structure will also support handling UNION ALL
subqueries in the same way as inheritance sets, but that aspect of it isn't
finished yet.

1 files changed, 33 insertions, 83 deletions

diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index cef0c63a66..cedb808227 100644
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.74 2005/12/20 02:30:36 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.75 2006/01/31 21:39:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,8 +30,6 @@ typedef struct JoinHashEntry
 	RelOptInfo *join_rel;
 } JoinHashEntry;
 
-static RelOptInfo *make_reloptinfo(PlannerInfo *root, int relid,
-				RelOptKind reloptkind);
 static void build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
 					RelOptInfo *input_rel);
 static List *build_joinrel_restrictlist(PlannerInfo *root,
@@ -49,71 +47,25 @@ static void subbuild_joinrel_joinlist(RelOptInfo *joinrel,
 
 
 /*
- * build_base_rel
- *	  Construct a new base relation RelOptInfo, and put it in the query's
- *	  base_rel_array.
- */
-void
-build_base_rel(PlannerInfo *root, int relid)
-{
-	Assert(relid > 0);
-
-	/* Rel should not exist already */
-	if (relid < root->base_rel_array_size &&
-		root->base_rel_array[relid] != NULL)
-		elog(ERROR, "rel already exists");
-
-	/* No existing RelOptInfo for this base rel, so make a new one */
-	(void) make_reloptinfo(root, relid, RELOPT_BASEREL);
-}
-
-/*
- * build_other_rel
- *	  Returns relation entry corresponding to 'relid', creating a new one
- *	  if necessary.  This is for 'other' relations, which are much like
- *	  base relations except that they have a different RelOptKind.
+ * build_simple_rel
+ *	  Construct a new RelOptInfo for a base relation or 'other' relation.
  */
 RelOptInfo *
-build_other_rel(PlannerInfo *root, int relid)
+build_simple_rel(PlannerInfo *root, int relid, RelOptKind reloptkind)
 {
 	RelOptInfo *rel;
+	RangeTblEntry *rte;
 
-	Assert(relid > 0);
-
-	/* Already made? */
-	if (relid < root->base_rel_array_size)
-	{
-		rel = root->base_rel_array[relid];
-		if (rel)
-		{
-			/* it should not exist as a base rel */
-			if (rel->reloptkind == RELOPT_BASEREL)
-				elog(ERROR, "rel already exists as base rel");
-			/* otherwise, A-OK */
-			return rel;
-		}
-	}
+	/* Fetch RTE for relation */
+	Assert(relid > 0 && relid <= list_length(root->parse->rtable));
+	rte = rt_fetch(relid, root->parse->rtable);
 
-	/* No existing RelOptInfo for this other rel, so make a new one */
-	/* presently, must be an inheritance child rel */
-	rel = make_reloptinfo(root, relid, RELOPT_OTHER_CHILD_REL);
-
-	return rel;
-}
-
-/*
- * make_reloptinfo
- *	  Construct a RelOptInfo for the specified rangetable index,
- *	  and enter it into base_rel_array.
- *
- * Common code for build_base_rel and build_other_rel.
- */
-static RelOptInfo *
-make_reloptinfo(PlannerInfo *root, int relid, RelOptKind reloptkind)
-{
-	RelOptInfo *rel = makeNode(RelOptInfo);
-	RangeTblEntry *rte = rt_fetch(relid, root->parse->rtable);
+	/* Rel should not exist already */
+	Assert(relid < root->simple_rel_array_size);
+	if (root->simple_rel_array[relid] != NULL)
+		elog(ERROR, "rel %d already exists", relid);
 
+	rel = makeNode(RelOptInfo);
 	rel->reloptkind = reloptkind;
 	rel->relids = bms_make_singleton(relid);
 	rel->rows = 0;
@@ -161,21 +113,8 @@ make_reloptinfo(PlannerInfo *root, int relid, RelOptKind reloptkind)
 			break;
 	}
 
-	/* Add the finished struct to the base_rel_array */
-	if (relid >= root->base_rel_array_size)
-	{
-		int			oldsize = root->base_rel_array_size;
-		int			newsize;
-
-		newsize = Max(oldsize * 2, relid + 1);
-		root->base_rel_array = (RelOptInfo **)
-			repalloc(root->base_rel_array, newsize * sizeof(RelOptInfo *));
-		MemSet(root->base_rel_array + oldsize, 0,
-			   (newsize - oldsize) * sizeof(RelOptInfo *));
-		root->base_rel_array_size = newsize;
-	}
-
-	root->base_rel_array[relid] = rel;
+	/* Save the finished struct in the query's simple_rel_array */
+	root->simple_rel_array[relid] = rel;
 
 	return rel;
 }
@@ -191,9 +130,9 @@ find_base_rel(PlannerInfo *root, int relid)
 
 	Assert(relid > 0);
 
-	if (relid < root->base_rel_array_size)
+	if (relid < root->simple_rel_array_size)
 	{
-		rel = root->base_rel_array[relid];
+		rel = root->simple_rel_array[relid];
 		if (rel)
 			return rel;
 	}
@@ -446,12 +385,24 @@ build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
 
 	foreach(vars, input_rel->reltargetlist)
 	{
-		Var		   *var = (Var *) lfirst(vars);
+		Var		   *origvar = (Var *) lfirst(vars);
+		Var		   *var;
 		RelOptInfo *baserel;
 		int			ndx;
 
-		/* We can't run into any child RowExprs here */
-		Assert(IsA(var, Var));
+		/*
+		 * We can't run into any child RowExprs here, but we could find
+		 * a whole-row Var with a ConvertRowtypeExpr atop it.
+		 */
+		var = origvar;
+		while (!IsA(var, Var))
+		{
+			if (IsA(var, ConvertRowtypeExpr))
+				var = (Var *) ((ConvertRowtypeExpr *) var)->arg;
+			else
+				elog(ERROR, "unexpected node type in reltargetlist: %d",
+					 (int) nodeTag(var));
+		}
 
 		/* Get the Var's original base rel */
 		baserel = find_base_rel(root, var->varno);
@@ -461,8 +412,7 @@ build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
 		if (bms_nonempty_difference(baserel->attr_needed[ndx], relids))
 		{
 			/* Yup, add it to the output */
-			joinrel->reltargetlist = lappend(joinrel->reltargetlist, var);
-			Assert(baserel->attr_widths[ndx] > 0);
+			joinrel->reltargetlist = lappend(joinrel->reltargetlist, origvar);
 			joinrel->width += baserel->attr_widths[ndx];
 		}
 	}