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Fix GEQO optimizer to work correctly with new outer-join-capable

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query representation.  Note that GEQO_RELS setting is now interpreted
as the number of top-level items in the FROM list, not necessarily the
number of relations in the query.  This seems appropriate since we are
only doing join-path searching over the top-level items.
This commit is contained in:
Tom Lane
2000-09-19 18:42:34 +00:00
parent 457ac0331c
commit ba2ea6e0f5
6 changed files with 57 additions and 48 deletions
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50
src/backend/optimizer/geqo/geqo_eval.c
View File

@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: geqo_eval.c,v 1.54 2000/09/12 21:06:50 tgl Exp $
* $Id: geqo_eval.c,v 1.55 2000/09/19 18:42:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -36,7 +36,7 @@
* Returns cost of a query tree as an individual of the population.
*/
Cost
geqo_eval(Query *root, Gene *tour, int num_gene)
geqo_eval(Query *root, List *initial_rels, Gene *tour, int num_gene)
{
MemoryContext mycontext;
MemoryContext oldcxt;
@ -64,7 +64,7 @@ geqo_eval(Query *root, Gene *tour, int num_gene)
savelist = root->join_rel_list;
/* construct the best path for the given combination of relations */
joinrel = gimme_tree(root, tour, 0, num_gene, NULL);
joinrel = gimme_tree(root, initial_rels, tour, num_gene, 0, NULL);
/*
* compute fitness
@ -86,35 +86,42 @@ geqo_eval(Query *root, Gene *tour, int num_gene)
/*
* gimme_tree
* this program presumes that only LEFT-SIDED TREES are considered!
* this routine considers only LEFT-SIDED TREES!
*
* 'old_rel' is the preceding join
* 'root' is the Query
* 'initial_rels' is the list of initial relations (FROM-list items)
* 'tour' is the proposed join order, of length 'num_gene'
* 'rel_count' is number of initial_rels items already joined (initially 0)
* 'old_rel' is the preceding join (initially NULL)
*
* Returns a new join relation incorporating all joins in a left-sided tree.
*/
RelOptInfo *
gimme_tree(Query *root, Gene *tour, int rel_count, int num_gene,
RelOptInfo *old_rel)
gimme_tree(Query *root, List *initial_rels,
Gene *tour, int num_gene,
int rel_count, RelOptInfo *old_rel)
{
RelOptInfo *inner_rel; /* current relation */
int base_rel_index;
int init_rel_index;
if (rel_count < num_gene)
{ /* tree not yet finished */
{
/* tree not yet finished */
init_rel_index = (int) tour[rel_count];
/* tour[0] = 3; tour[1] = 1; tour[2] = 2 */
base_rel_index = (int) tour[rel_count];
inner_rel = (RelOptInfo *) nth(base_rel_index - 1, root->base_rel_list);
inner_rel = (RelOptInfo *) nth(init_rel_index - 1, initial_rels);
if (rel_count == 0)
{ /* processing first join with
* base_rel_index = (int) tour[0] */
{
/* processing first join with init_rel_index = (int) tour[0] */
rel_count++;
return gimme_tree(root, tour, rel_count, num_gene, inner_rel);
return gimme_tree(root, initial_rels,
tour, num_gene,
rel_count, inner_rel);
}
else
{ /* tree main part */
{
/* tree main part */
List *acceptable_rels = lcons(inner_rel, NIL);
List *new_rels;
RelOptInfo *new_rel;
@ -133,13 +140,14 @@ gimme_tree(Query *root, Gene *tour, int rel_count, int num_gene,
}
new_rel = (RelOptInfo *) lfirst(new_rels);
rel_count++;
Assert(length(new_rel->relids) == rel_count);
/* Find and save the cheapest paths for this rel */
set_cheapest(new_rel);
return gimme_tree(root, tour, rel_count, num_gene, new_rel);
/* and recurse... */
rel_count++;
return gimme_tree(root, initial_rels,
tour, num_gene,
rel_count, new_rel);
}
}

20
src/backend/optimizer/geqo/geqo_main.c
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: geqo_main.c,v 1.23 2000/08/07 00:51:23 tgl Exp $
* $Id: geqo_main.c,v 1.24 2000/09/19 18:42:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -65,13 +65,12 @@ static int gimme_number_generations(int pool_size, int effort);
*/
RelOptInfo *
geqo(Query *root)
geqo(Query *root, int number_of_rels, List *initial_rels)
{
int generation;
Chromosome *momma;
Chromosome *daddy;
Chromosome *kid;
int number_of_rels;
Pool *pool;
int pool_size,
number_generations,
@ -95,9 +94,6 @@ geqo(Query *root)
#endif
/* set tour size */
number_of_rels = length(root->base_rel_list);
/* set GA parameters */
pool_size = gimme_pool_size(number_of_rels);
number_generations = gimme_number_generations(pool_size, Geqo_effort);
@ -114,7 +110,7 @@ geqo(Query *root)
pool = alloc_pool(pool_size, number_of_rels);
/* random initialization of the pool */
random_init_pool(root, pool, 0, pool->size);
random_init_pool(root, initial_rels, pool, 0, pool->size);
/* sort the pool according to cheapest path as fitness */
sort_pool(pool); /* we have to do it only one time, since
@ -204,7 +200,8 @@ geqo(Query *root)
/* EVALUATE FITNESS */
kid->worth = geqo_eval(root, kid->string, pool->string_length);
kid->worth = geqo_eval(root, initial_rels,
kid->string, pool->string_length);
/* push the kid into the wilderness of life according to its worth */
spread_chromo(kid, pool);
@ -247,9 +244,10 @@ geqo(Query *root)
best_tour = (Gene *) pool->data[0].string;
/* root->join_relation_list_ will be modified during this ! */
best_rel = (RelOptInfo *) gimme_tree(root, best_tour, 0,
pool->string_length, NULL);
/* root->join_rel_list will be modified during this ! */
best_rel = (RelOptInfo *) gimme_tree(root, initial_rels,
best_tour, pool->string_length,
0, NULL);
/* DBG: show the query plan
print_plan(best_plan, root);

14
src/backend/optimizer/geqo/geqo_pool.c
View File

@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: geqo_pool.c,v 1.17 2000/01/26 05:56:33 momjian Exp $
* $Id: geqo_pool.c,v 1.18 2000/09/19 18:42:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -84,18 +84,18 @@ free_pool(Pool *pool)
* initialize genetic pool
*/
void
random_init_pool(Query *root, Pool *pool, int strt, int stp)
random_init_pool(Query *root, List *initial_rels,
Pool *pool, int strt, int stp)
{
Chromosome *chromo = (Chromosome *) pool->data;
int i;
for (i = strt; i < stp; i++)
{
init_tour(chromo[i].string, pool->string_length); /* from
* "geqo_recombination.c"
* */
pool->data[i].worth = geqo_eval(root, chromo[i].string, pool->string_length); /* "from geqo_eval.c" */
init_tour(chromo[i].string, pool->string_length);
pool->data[i].worth = geqo_eval(root, initial_rels,
chromo[i].string,
pool->string_length);
}
}

4
src/backend/optimizer/path/allpaths.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.63 2000/09/12 21:06:52 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/allpaths.c,v 1.64 2000/09/19 18:42:34 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -188,7 +188,7 @@ make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels)
* rest will be skipped in case of GEQO *
*******************************************/
if (enable_geqo && levels_needed >= geqo_rels)
return geqo(root);
return geqo(root, levels_needed, initial_rels);
/*
* We employ a simple "dynamic programming" algorithm: we first find