Merge in GEQO Optimizer

From: "Martin S. Utesch" <utesch@aut.tu-freiberg.de>

1 files changed, 145 insertions, 0 deletions

diff --git a/src/backend/optimizer/geqo/geqo_paths.c b/src/backend/optimizer/geqo/geqo_paths.c
new file mode 100644
index 00000000000..c6a7ce512b7
--- /dev/null
+++ b/src/backend/optimizer/geqo/geqo_paths.c
@@ -0,0 +1,145 @@
+/*-------------------------------------------------------------------------
+ *
+ * geqo_paths.c--
+ *    Routines to process redundant paths and relations
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: geqo_paths.c,v 1.1 1997/02/19 12:57:25 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "nodes/pg_list.h"
+#include "nodes/relation.h"
+#include "nodes/primnodes.h"
+
+#include "utils/palloc.h"
+#include "utils/elog.h"
+
+#include "optimizer/internal.h"
+#include "optimizer/paths.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/clauses.h"
+#include "optimizer/cost.h"
+
+#include "optimizer/geqo_paths.h"
+
+
+static List *geqo_prune_rel(Rel *rel, List *other_rels);
+static Path *set_paths(Rel *rel, Path *unorderedpath);
+
+/*    
+ * geqo-prune-rels--
+ *    Removes any redundant relation entries from a list of rel nodes
+ *    'rel-list'.
+ *    
+ * Returns the resulting list. 
+ *    
+ */
+List *geqo_prune_rels(List *rel_list)
+{
+    List *temp_list = NIL;
+
+    if (rel_list != NIL) {
+	temp_list = lcons(lfirst(rel_list),
+			 geqo_prune_rels(geqo_prune_rel((Rel*)lfirst(rel_list),
+						      lnext(rel_list))));
+    } 
+    return(temp_list);
+}
+
+/*    
+ * geqo-prune-rel--
+ *    Prunes those relations from 'other-rels' that are redundant with
+ *    'rel'.  A relation is redundant if it is built up of the same
+ *    relations as 'rel'.  Paths for the redundant relation are merged into
+ *    the pathlist of 'rel'.
+ *    
+ * Returns a list of non-redundant relations, and sets the pathlist field
+ * of 'rel' appropriately.
+ *    
+ */
+static List *
+geqo_prune_rel(Rel *rel, List *other_rels) 
+{
+    List *i = NIL;
+    List *t_list = NIL;
+    List *temp_node = NIL;
+    Rel *other_rel = (Rel *)NULL;
+    
+    foreach(i, other_rels) {
+	other_rel = (Rel*)lfirst(i);
+	if(same(rel->relids, other_rel->relids)) {
+	    rel->pathlist = add_pathlist(rel,
+					 rel->pathlist,
+					 other_rel->pathlist);
+	    t_list = nconc(t_list, NIL);  /* XXX is this right ? */
+	} else {
+	    temp_node = lcons(other_rel, NIL);
+	    t_list = nconc(t_list,temp_node);
+	} 
+    }
+    return(t_list);
+}
+
+/*    
+ * geqo-rel-paths--
+ *    For a relation 'rel' (which corresponds to a join
+ *    relation), set pointers to the unordered path and cheapest paths
+ *    (if the unordered path isn't the cheapest, it is pruned), and
+ *    reset the relation's size field to reflect the join.
+ *    
+ * Returns nothing of interest.
+ *    
+ */
+void
+geqo_rel_paths(Rel *rel)
+{
+    List *y = NIL;
+    Path *path;
+    JoinPath *cheapest = (JoinPath*)NULL;
+    
+	foreach(y, rel->pathlist) {
+		path = (Path*)lfirst(y);
+
+	   if(!path->p_ordering.ord.sortop) {
+			break;
+		    }	    
+		}
+
+	cheapest = (JoinPath*)set_paths(rel, path);
+	rel->size = compute_joinrel_size(cheapest);
+}
+
+
+/*    
+ * set-path--
+ *    Compares the unordered path for a relation with the cheapest path. If
+ *    the unordered path is not cheapest, it is pruned.
+ *    
+ *    Resets the pointers in 'rel' for unordered and cheapest paths.
+ *    
+ * Returns the cheapest path.
+ *    
+ */
+static Path *
+set_paths(Rel *rel, Path *unorderedpath)
+{
+    Path *cheapest = set_cheapest(rel, rel->pathlist);
+    
+    /* don't prune if not pruneable  -- JMH, 11/23/92 */
+    if(unorderedpath != cheapest 
+       && rel->pruneable) {
+	
+	rel->unorderedpath = (Path *)NULL;
+	rel->pathlist = lremove(unorderedpath, rel->pathlist);
+    } else {
+	rel->unorderedpath = (Path *)unorderedpath;
+    } 
+    
+    return(cheapest);
+}
+