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optimizer cleanup

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This commit is contained in:
Bruce Momjian 1999-02-19 02:05:20 +00:00
parent 61f40ac3f2
commit 8ab72a38df
5 changed files with 76 additions and 77 deletions
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16
src/backend/optimizer/README
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@ -5,12 +5,14 @@ The optimizer generates optimial query plans by doing several steps:
1) Take each relation in a query, and make a RelOptInfo structure for
it. Find each way of accessing the relation, called a Path, including
sequential and index scans, and add it to RelOptInfo.pathlist.
sequential and index scans, and add it to RelOptInfo.pathlist. Also
create RelOptInfo.joininfo that lists all the joins that involve this
relation.
2) Join each RelOptInfo to each other RelOptInfo as specified in the
WHERE clause. At this point each RelOptInfo is a single relation, so
you are joining every relation to every relation as joined in the WHERE
clause.
2) Join each RelOptInfo to other RelOptInfo as specified in
RelOptInfo.joininfo. At this point each RelOptInfo is a single
relation, so you are joining every relation to the other relations as
joined in the WHERE clause.
Joins occur using two RelOptInfos. One is outer, the other inner.
Outers drive lookups of values in the inner. In a nested loop, lookups
@ -137,8 +139,8 @@ Optimizer Structures
RelOptInfo - a relation or joined relations
RestrictInfo - restriction clauses
JoinInfo - join clauses
RestrictInfo - restriction clauses, like "x = 3"
JoinInfo - join clauses, including the relids needed for the join
Path - every way to generate a RelOptInfo(sequential,index,joins)
IndexPath - index scans

115
src/backend/optimizer/path/pathkey.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/pathkey.c,v 1.1 1999/02/18 19:58:52 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/pathkey.c,v 1.2 1999/02/19 02:05:15 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -27,9 +27,9 @@
static int match_pathkey_joinkeys(List *pathkey, List *joinkeys,
int which_subkey);
int outer_or_inner);
static bool every_func(List *joinkeys, List *pathkey,
int which_subkey);
int outer_or_inner);
static List *new_join_pathkey(List *subkeys, List *considered_subkeys,
List *join_rel_tlist, List *joinclauses);
static List *new_matching_subkeys(Var *subkey, List *considered_subkeys,
@ -54,7 +54,7 @@ static List *new_matching_subkeys(Var *subkey, List *considered_subkeys,
* ( (outer inner) (outer inner) ... )
* 'joinclauses' is a list of clauses corresponding to the join keys in
* 'joinkeys'
* 'which_subkey' is a flag that selects the desired subkey of a join key
* 'outer_or_inner' is a flag that selects the desired subkey of a join key
* in 'joinkeys'
*
* Returns the join keys and corresponding join clauses in a list if all
@ -72,7 +72,7 @@ List *
match_pathkeys_joinkeys(List *pathkeys,
List *joinkeys,
List *joinclauses,
int which_subkey,
int outer_or_inner,
List **matchedJoinClausesPtr)
{
List *matched_joinkeys = NIL;
@ -84,19 +84,17 @@ match_pathkeys_joinkeys(List *pathkeys,
foreach(i, pathkeys)
{
pathkey = lfirst(i);
matched_joinkey_index = match_pathkey_joinkeys(pathkey, joinkeys, which_subkey);
matched_joinkey_index = match_pathkey_joinkeys(pathkey, joinkeys,
outer_or_inner);
if (matched_joinkey_index != -1)
{
List *xjoinkey = nth(matched_joinkey_index, joinkeys);
List *joinclause = nth(matched_joinkey_index, joinclauses);
/* XXX was "push" function */
matched_joinkeys = lappend(matched_joinkeys, xjoinkey);
matched_joinkeys = nreverse(matched_joinkeys);
matched_joinkeys = lcons(xjoinkey, matched_joinkeys);
matched_joinclauses = lcons(joinclause, matched_joinclauses);
matched_joinclauses = lappend(matched_joinclauses, joinclause);
matched_joinclauses = nreverse(matched_joinclauses);
joinkeys = LispRemove(xjoinkey, joinkeys);
}
else
@ -111,6 +109,7 @@ match_pathkeys_joinkeys(List *pathkeys,
return nreverse(matched_joinkeys);
}
/*
* match_pathkey_joinkeys
* Returns the 0-based index into 'joinkeys' of the first joinkey whose
@ -119,7 +118,7 @@ match_pathkeys_joinkeys(List *pathkeys,
static int
match_pathkey_joinkeys(List *pathkey,
List *joinkeys,
int which_subkey)
int outer_or_inner)
{
Var *path_subkey;
int pos;
@ -135,7 +134,7 @@ match_pathkey_joinkeys(List *pathkey,
{
jk = (JoinKey *) lfirst(x);
if (var_equal(path_subkey,
extract_join_subkey(jk, which_subkey)))
extract_join_key(jk, outer_or_inner)))
return pos;
pos++;
}
@ -143,6 +142,7 @@ match_pathkey_joinkeys(List *pathkey,
return -1; /* no index found */
}
/*
* match_paths_joinkeys
* Attempts to find a path in 'paths' whose keys match a set of join
@ -159,53 +159,16 @@ match_pathkey_joinkeys(List *pathkey,
* must correspond
* 'paths' is a list of(inner) paths which are to be matched against
* each join key in 'joinkeys'
* 'which_subkey' is a flag that selects the desired subkey of a join key
* 'outer_or_inner' is a flag that selects the desired subkey of a join key
* in 'joinkeys'
*
* Returns the matching path node if one exists, nil otherwise.
*/
static bool
every_func(List *joinkeys, List *pathkey, int which_subkey)
{
JoinKey *xjoinkey;
Var *temp;
Var *tempkey = NULL;
bool found = false;
List *i = NIL;
List *j = NIL;
foreach(i, joinkeys)
{
xjoinkey = (JoinKey *) lfirst(i);
found = false;
foreach(j, pathkey)
{
temp = (Var *) lfirst((List *) lfirst(j));
if (temp == NULL)
continue;
tempkey = extract_join_subkey(xjoinkey, which_subkey);
if (var_equal(tempkey, temp))
{
found = true;
break;
}
}
if (found == false)
return false;
}
return found;
}
/*
* match_paths_joinkeys -
* find the cheapest path that matches the join keys
* Find the cheapest path that matches the join keys
*/
Path *
match_paths_joinkeys(List *joinkeys,
PathOrder *ordering,
List *paths,
int which_subkey)
int outer_or_inner)
{
Path *matched_path = NULL;
bool key_match = false;
@ -216,13 +179,12 @@ match_paths_joinkeys(List *joinkeys,
Path *path = (Path *) lfirst(i);
int better_sort;
key_match = every_func(joinkeys, path->pathkeys, which_subkey);
key_match = every_func(joinkeys, path->pathkeys, outer_or_inner);
if (pathorder_match(ordering, path->pathorder, &better_sort) &&
better_sort == 0 &&
length(joinkeys) == length(path->pathkeys) && key_match)
{
if (matched_path)
{
if (path->path_cost < matched_path->path_cost)
@ -236,7 +198,6 @@ match_paths_joinkeys(List *joinkeys,
}
/*
* extract_path_keys
* Builds a subkey list for a path by pulling one of the subkeys from
@ -245,7 +206,7 @@ match_paths_joinkeys(List *joinkeys,
*
* 'joinkeys' is a list of join key pairs
* 'tlist' is a relation target list
* 'which_subkey' is a flag that selects the desired subkey of a join key
* 'outer_or_inner' is a flag that selects the desired subkey of a join key
* in 'joinkeys'
*
* Returns a list of pathkeys: ((tlvar1)(tlvar2)...(tlvarN)).
@ -254,7 +215,7 @@ match_paths_joinkeys(List *joinkeys,
List *
extract_path_keys(List *joinkeys,
List *tlist,
int which_subkey)
int outer_or_inner)
{
List *pathkeys = NIL;
List *jk;
@ -269,7 +230,7 @@ extract_path_keys(List *joinkeys,
/*
* find the right Var in the target list for this key
*/
var = (Var *) extract_join_subkey(jkey, which_subkey);
var = (Var *) extract_join_key(jkey, outer_or_inner);
key = (Var *) matching_tlist_var(var, tlist);
/*
@ -291,6 +252,42 @@ extract_path_keys(List *joinkeys,
}
/*
* every_func
*/
static bool
every_func(List *joinkeys, List *pathkey, int outer_or_inner)
{
JoinKey *xjoinkey;
Var *temp;
Var *tempkey = NULL;
bool found = false;
List *i = NIL;
List *j = NIL;
foreach(i, joinkeys)
{
xjoinkey = (JoinKey *) lfirst(i);
found = false;
foreach(j, pathkey)
{
temp = (Var *) lfirst((List *) lfirst(j));
if (temp == NULL)
continue;
tempkey = extract_join_key(xjoinkey, outer_or_inner);
if (var_equal(tempkey, temp))
{
found = true;
break;
}
}
if (found == false)
return false;
}
return found;
}
/****************************************************************************
* NEW PATHKEY FORMATION
****************************************************************************/

10
src/backend/optimizer/util/keys.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/Attic/keys.c,v 1.17 1999/02/13 23:16:45 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/Attic/keys.c,v 1.18 1999/02/19 02:05:16 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -80,17 +80,17 @@ equal_indexkey_var(int index_key, Var *var)
}
/*
* extract_join_subkey
* extract_join_key
* Returns the subkey in a join key corresponding to the outer or inner
* relation.
*
*/
Var *
extract_join_subkey(JoinKey *jk, int which_subkey)
extract_join_key(JoinKey *jk, int outer_or_inner)
{
Var *retval;
switch (which_subkey)
switch (outer_or_inner)
{
case OUTER:
retval = jk->outer;
@ -99,7 +99,7 @@ extract_join_subkey(JoinKey *jk, int which_subkey)
retval = jk->inner;
break;
default: /* do nothing */
elog(DEBUG, "extract_join_subkey with neither INNER or OUTER");
elog(DEBUG, "extract_join_key with neither INNER or OUTER");
retval = NULL;
}
return retval;

4
src/include/optimizer/keys.h
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@ -6,7 +6,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: keys.h,v 1.12 1999/02/13 23:21:49 momjian Exp $
* $Id: keys.h,v 1.13 1999/02/19 02:05:18 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -17,7 +17,7 @@
#include "nodes/relation.h"
extern bool match_indexkey_operand(int indexkey, Var *operand, RelOptInfo *rel);
extern Var *extract_join_subkey(JoinKey *jk, int which_subkey);
extern Var *extract_join_key(JoinKey *jk, int outer_or_inner);
extern bool pathkeys_match(List *keys1, List *keys2, int *better_key);
extern List *collect_index_pathkeys(int *index_keys, List *tlist);

8
src/include/optimizer/paths.h
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@ -7,7 +7,7 @@
*
* Copyright (c) 1994, Regents of the University of California
*
* $Id: paths.h,v 1.22 1999/02/18 04:45:36 momjian Exp $
* $Id: paths.h,v 1.23 1999/02/19 02:05:20 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -55,12 +55,12 @@ extern List *group_clauses_by_hashop(List *restrictinfo_list,
* generic join method key/clause routines
*/
extern List *match_pathkeys_joinkeys(List *pathkeys,
List *joinkeys, List *joinclauses, int which_subkey,
List *joinkeys, List *joinclauses, int outer_or_inner,
List **matchedJoinClausesPtr);
extern List *extract_path_keys(List *joinkeys, List *tlist,
int which_subkey);
int outer_or_inner);
extern Path *match_paths_joinkeys(List *joinkeys, PathOrder *ordering,
List *paths, int which_subkey);
List *paths, int outer_or_inner);
extern List *new_join_pathkeys(List *outer_pathkeys,
List *join_rel_tlist, List *joinclauses);