Postgres95 1.01 Distribution - Virgin Sources

src/backend/optimizer/path/hashutils.c

@@ -0,0 +1,120 @@
+/*-------------------------------------------------------------------------
+ *
+ * hashutils.c--
+ *    Utilities for finding applicable merge clauses and pathkeys
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/hashutils.c,v 1.1.1.1 1996/07/09 06:21:35 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+#include "nodes/pg_list.h"
+#include "nodes/relation.h"
+
+#include "optimizer/internal.h"
+#include "optimizer/paths.h"
+#include "optimizer/clauses.h"
+
+
+static HInfo *match_hashop_hashinfo(Oid hashop, List *hashinfo_list);
+
+/*    
+ * group-clauses-by-hashop--
+ *    If a join clause node in 'clauseinfo-list' is hashjoinable, store
+ *    it within a hashinfo node containing other clause nodes with the same
+ *    hash operator.
+ *    
+ * 'clauseinfo-list' is the list of clauseinfo nodes
+ * 'inner-relid' is the relid of the inner join relation
+ *    
+ * Returns the new list of hashinfo nodes.
+ *    
+ */
+List *
+group_clauses_by_hashop(List *clauseinfo_list,
+			int inner_relid)
+{
+    List *hashinfo_list = NIL;
+    CInfo *clauseinfo = (CInfo*)NULL;
+    List *i = NIL;
+    Oid hashjoinop = 0;
+    
+    foreach (i,clauseinfo_list) {
+	clauseinfo = (CInfo*)lfirst(i);
+	hashjoinop = clauseinfo->hashjoinoperator;
+	
+	/*
+	 * Create a new hashinfo node and add it to 'hashinfo-list' if one
+	 * does not yet exist for this hash operator.
+	 */
+	if (hashjoinop ) {
+	    HInfo *xhashinfo = (HInfo*)NULL;
+	    Expr *clause = clauseinfo->clause;
+	    Var *leftop = get_leftop(clause);
+	    Var *rightop = get_rightop(clause);
+	    JoinKey *keys = (JoinKey*)NULL;
+	    
+	    xhashinfo = 
+		match_hashop_hashinfo(hashjoinop,hashinfo_list);
+	    
+	    if (inner_relid == leftop->varno){
+		keys = makeNode(JoinKey);
+		keys->outer = rightop;
+		keys->inner = leftop;
+	    } else {
+		keys = makeNode(JoinKey);
+		keys->outer = leftop;
+		keys->inner = rightop;
+	    }
+	    
+	    if (xhashinfo==NULL) {
+		xhashinfo = makeNode(HInfo);
+		xhashinfo->hashop = hashjoinop;
+
+		xhashinfo->jmethod.jmkeys = NIL;
+		xhashinfo->jmethod.clauses = NIL;
+
+		/* XXX was push  */
+		hashinfo_list = lappend(hashinfo_list,xhashinfo);
+		hashinfo_list = nreverse(hashinfo_list);
+	    }
+
+	    xhashinfo->jmethod.clauses =
+		lcons(clause, xhashinfo->jmethod.clauses);
+
+	    xhashinfo->jmethod.jmkeys =
+		lcons(keys, xhashinfo->jmethod.jmkeys);
+	}
+    }
+    return(hashinfo_list);
+}
+
+
+/*    
+ * match-hashop-hashinfo--
+ *    Searches the list 'hashinfo-list' for a hashinfo node whose hash op
+ *    field equals 'hashop'.
+ *    
+ * Returns the node if it exists.
+ *    
+ */
+static HInfo *
+match_hashop_hashinfo(Oid hashop, List *hashinfo_list)
+{
+    Oid key = 0;
+    HInfo *xhashinfo = (HInfo*)NULL;
+    List *i = NIL;
+    
+    foreach( i, hashinfo_list) {
+	xhashinfo = (HInfo*)lfirst(i);
+	key = xhashinfo->hashop;
+	if (hashop == key) {	/* found */
+	    return(xhashinfo);	/* should be a hashinfo node ! */
+	}
+    }
+    return((HInfo*)NIL);
+}