Change GEQO optimizer to release memory after each gene
is evaluated. This bounds memory usage to something reasonable even when many tables are being joined.
This commit is contained in:
Tom Lane
parent
c686be8d56
commit
1332c1e144
@ -5,7 +5,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: geqo_eval.c,v 1.36 1999/05/16 19:45:00 tgl Exp $
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* $Id: geqo_eval.c,v 1.37 1999/05/17 00:25:34 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -36,6 +36,7 @@
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#include "utils/palloc.h"
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#include "utils/elog.h"
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#include "utils/portal.h"
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#include "optimizer/internal.h"
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#include "optimizer/paths.h"
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@ -48,6 +49,38 @@
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#include "optimizer/geqo_gene.h"
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#include "optimizer/geqo.h"
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/*
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* Variables set by geqo_eval_startup for use within a single GEQO run
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*/
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static MemoryContext geqo_eval_context;
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/*
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* geqo_eval_startup:
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* Must be called during geqo_main startup (before geqo_eval may be called)
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*
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* The main thing we need to do here is prepare a private memory context for
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* allocation of temp storage used while constructing a path in geqo_eval().
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* Since geqo_eval() will be called many times, we can't afford to let all
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* that memory go unreclaimed until end of statement. We use a special
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* named portal to hold the context, so that it will be freed even if
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* we abort via elog(ERROR). The working data is allocated in the portal's
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* heap memory context.
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*/
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void
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geqo_eval_startup(void)
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{
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#define GEQO_PORTAL_NAME "<geqo workspace>"
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Portal geqo_portal = GetPortalByName(GEQO_PORTAL_NAME);
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if (!PortalIsValid(geqo_portal)) {
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/* First time through (within current transaction, that is) */
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geqo_portal = CreatePortal(GEQO_PORTAL_NAME);
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Assert(PortalIsValid(geqo_portal));
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}
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geqo_eval_context = (MemoryContext) PortalGetHeapMemory(geqo_portal);
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}
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/*
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* geqo_eval
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*
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@ -56,23 +89,30 @@
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Cost
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geqo_eval(Query *root, Gene *tour, int num_gene)
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{
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RelOptInfo *joinrel;
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Cost fitness;
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List *temp;
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MemoryContext oldcxt;
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RelOptInfo *joinrel;
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Cost fitness;
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List *savelist;
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/* remember root->join_rel_list ... */
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/* because root->join_rel_list will be changed during the following */
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temp = listCopy(root->join_rel_list);
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/* preserve root->join_rel_list, which gimme_tree changes */
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savelist = root->join_rel_list;
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/* joinrel is readily processed query tree -- left-sided ! */
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/* create a temporary allocation context for the path construction work */
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oldcxt = MemoryContextSwitchTo(geqo_eval_context);
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StartPortalAllocMode(DefaultAllocMode, 0);
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/* construct the best path for the given combination of relations */
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joinrel = gimme_tree(root, tour, 0, num_gene, NULL);
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/* compute fitness */
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fitness = (Cost) joinrel->cheapestpath->path_cost;
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root->join_rel_list = temp;
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/* restore join_rel_list */
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root->join_rel_list = savelist;
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pfree(joinrel);
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/* release all the memory acquired within gimme_tree */
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EndPortalAllocMode();
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MemoryContextSwitchTo(oldcxt);
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return fitness;
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}
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@ -6,7 +6,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: geqo_main.c,v 1.14 1999/02/18 04:55:54 momjian Exp $
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* $Id: geqo_main.c,v 1.15 1999/05/17 00:25:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -70,44 +70,31 @@ geqo(Query *root)
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Chromosome *momma;
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Chromosome *daddy;
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Chromosome *kid;
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#if defined(ERX)
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Edge *edge_table; /* list of edges */
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int edge_failures = 0;
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float difference;
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#endif
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#if defined(CX) || defined(PX) || defined(OX1) || defined(OX2)
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City *city_table; /* list of cities */
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#endif
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#if defined(CX)
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int cycle_diffs = 0;
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int mutations = 0;
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#endif
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int number_of_rels;
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Pool *pool;
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int pool_size,
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number_generations,
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status_interval;
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Gene *best_tour;
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RelOptInfo *best_rel;
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/* Plan *best_plan; */
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#if defined(ERX)
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Edge *edge_table; /* list of edges */
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int edge_failures = 0;
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float difference;
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#endif
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#if defined(CX) || defined(PX) || defined(OX1) || defined(OX2)
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City *city_table; /* list of cities */
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#endif
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#if defined(CX)
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int cycle_diffs = 0;
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int mutations = 0;
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#endif
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/* set tour size */
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number_of_rels = length(root->base_rel_list);
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/* set GA parameters */
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geqo_params(number_of_rels);/* out of "$PGDATA/pg_geqo" file */
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geqo_params(number_of_rels); /* read "$PGDATA/pg_geqo" file */
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pool_size = PoolSize;
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number_generations = Generations;
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status_interval = 10;
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@ -115,6 +102,9 @@ geqo(Query *root)
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/* seed random number generator */
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srandom(RandomSeed);
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/* initialize plan evaluator */
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geqo_eval_startup();
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/* allocate genetic pool memory */
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pool = alloc_pool(pool_size, number_of_rels);
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@ -5,7 +5,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: geqo_params.c,v 1.14 1999/02/15 03:22:01 momjian Exp $
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* $Id: geqo_params.c,v 1.15 1999/05/17 00:25:33 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -45,6 +45,16 @@
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#include "storage/fd.h"
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/*
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* Parameter values read from the config file (or defaulted) are stored here
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* by geqo_params().
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*/
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int PoolSize;
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int Generations;
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long RandomSeed;
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double SelectionBias;
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#define POOL_TAG "Pool_Size"
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#define TRIAL_TAG "Generations"
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#define RAND_TAG "Random_Seed"
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@ -77,7 +87,7 @@ geqo_params(int string_length)
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char *conf_file;
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/* these static variables are used to signal that a value has been set */
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/* these flag variables signal that a value has been set from the file */
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int pool_size = 0;
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int number_trials = 0;
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int random_seed = 0;
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@ -5,7 +5,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: geqo.h,v 1.13 1999/02/18 04:55:54 momjian Exp $
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* $Id: geqo.h,v 1.14 1999/05/17 00:25:32 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -56,27 +56,22 @@
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#define SELECTION_BIAS 2.0 /* selective pressure within population */
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/* should be 1.5 <= SELECTION_BIAS <= 2.0 */
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int PoolSize;
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int Generations;
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/* parameter values set in geqo_params.c */
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extern int PoolSize;
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extern int Generations;
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extern long RandomSeed;
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extern double SelectionBias;
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long RandomSeed; /* defaults to (long) time(NULL) in
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* geqo_params.c */
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double SelectionBias;
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/* logarithmic base for rel->size decrease in case of long
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queries that cause an integer overflow; used in geqo_eval.c */
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#define GEQO_LOG_BASE 1.5 /* should be 1.0 < GEQO_LOG_BASE <= 2.0 */
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/* ^^^ */
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/* geqo prototypes */
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/* routines in geqo_main.c */
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extern RelOptInfo *geqo(Query *root);
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/* routines in geqo_params.c */
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extern void geqo_params(int string_length);
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/* routines in geqo_eval.c */
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extern void geqo_eval_startup(void);
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extern Cost geqo_eval(Query *root, Gene *tour, int num_gene);
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extern RelOptInfo *gimme_tree(Query *root, Gene *tour, int rel_count,
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int num_gene, RelOptInfo *old_rel);
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#endif /* GEQO_H */
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