From e6381966c1886badbc19c94ac1f1ffbc104125ab Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 16 Aug 1999 02:17:58 +0000
Subject: Major planner/optimizer revision: get rid of PathOrder node type,
 store all ordering information in pathkeys lists (which are now lists of
 lists of PathKeyItem nodes, not just lists of lists of vars).  This was a big
 win --- the code is smaller and IMHO more understandable than it was, even
 though it handles more cases.  I believe the node changes will not force an
 initdb for anyone; planner nodes don't show up in stored rules.

---
 src/backend/optimizer/path/mergeutils.c | 131 --------------------------------
 1 file changed, 131 deletions(-)
 delete mode 100644 src/backend/optimizer/path/mergeutils.c

(limited to 'src/backend/optimizer/path/mergeutils.c')

diff --git a/src/backend/optimizer/path/mergeutils.c b/src/backend/optimizer/path/mergeutils.c
deleted file mode 100644
index 1cc19693f8d..00000000000
--- a/src/backend/optimizer/path/mergeutils.c
+++ /dev/null
@@ -1,131 +0,0 @@
-/*-------------------------------------------------------------------------
- *
- * mergeutils.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/mergeutils.c,v 1.24 1999/07/16 04:59:15 momjian Exp $
- *
- *-------------------------------------------------------------------------
- */
-#include "postgres.h"
-
-
-#include "optimizer/clauses.h"
-#include "optimizer/ordering.h"
-#include "optimizer/paths.h"
-
-/*
- * group_clauses_by_order
- *	  If a join clause node in 'restrictinfo_list' is mergejoinable, store
- *	  it within a mergeinfo node containing other clause nodes with the same
- *	  mergejoin ordering.
- *
- * XXX This is completely braindead: there is no reason anymore to segregate
- * mergejoin clauses by join operator, since the executor can handle mergejoin
- * clause sets with different operators in them.  Instead, we ought to be
- * building a MergeInfo for each potentially useful ordering of the input
- * relations.  But right now the optimizer's internal data structures do not
- * support that (MergeInfo can only store one MergeOrder for a set of clauses).
- * Something to fix next time...
- *
- * 'restrictinfo_list' is the list of restrictinfo nodes
- * '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,
-					   Relids inner_relids)
-{
-	List	   *mergeinfo_list = NIL;
-	List	   *xrestrictinfo;
-
-	foreach(xrestrictinfo, restrictinfo_list)
-	{
-		RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(xrestrictinfo);
-		MergeOrder *merge_ordering = restrictinfo->mergejoinorder;
-
-		if (merge_ordering)
-		{
-
-			/*
-			 * Create a new mergeinfo node and add it to 'mergeinfo_list'
-			 * if one does not yet exist for this merge ordering.
-			 */
-			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);
-			jmkeys = makeNode(JoinKey);
-			if (intMember(leftop->varno, inner_relids))
-			{
-				jmkeys->outer = rightop;
-				jmkeys->inner = leftop;
-			}
-			else
-			{
-				jmkeys->outer = leftop;
-				jmkeys->inner = rightop;
-			}
-
-			if (xmergeinfo == NULL)
-			{
-				xmergeinfo = makeNode(MergeInfo);
-				xmergeinfo->m_ordering = merge_ordering;
-				mergeinfo_list = lcons(xmergeinfo, mergeinfo_list);
-			}
-
-			xmergeinfo->jmethod.clauses = lcons(clause,
-											xmergeinfo->jmethod.clauses);
-			xmergeinfo->jmethod.jmkeys = lcons(jmkeys,
-											 xmergeinfo->jmethod.jmkeys);
-		}
-	}
-	return mergeinfo_list;
-}
-
-
-/*
- * match_order_mergeinfo
- *	  Searches the list 'mergeinfo_list' for a mergeinfo node whose order
- *	  field equals 'ordering'.
- *
- * Returns the node if it exists.
- *
- */
-MergeInfo  *
-match_order_mergeinfo(PathOrder *ordering, List *mergeinfo_list)
-{
-	MergeOrder *xmergeorder;
-	List	   *xmergeinfo = NIL;
-
-	foreach(xmergeinfo, mergeinfo_list)
-	{
-		MergeInfo  *mergeinfo = (MergeInfo *) lfirst(xmergeinfo);
-
-		xmergeorder = mergeinfo->m_ordering;
-
-		if ((ordering->ordtype == MERGE_ORDER &&
-			 equal_merge_ordering(ordering->ord.merge, xmergeorder)) ||
-			(ordering->ordtype == SORTOP_ORDER &&
-		   equal_path_merge_ordering(ordering->ord.sortop, xmergeorder)))
-		{
-
-			return mergeinfo;
-		}
-	}
-	return (MergeInfo *) NIL;
-}
-- 
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