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random number seed each time. This is how it used to work years ago, but we got rid of the seed reset because it was resetting the main random() sequence and thus having undesirable effects on the rest of the system. To fix, establish a private random number state for each execution of geqo(), and initialize the state using the new GUC variable geqo_seed. People who want to experiment with different random searches can do so by changing geqo_seed, but you'll always get the same plan for the same value of geqo_seed (if holding all other planner inputs constant, of course). The new state is kept in PlannerInfo by adding a "void *" field reserved for use by join_search hooks. Most of the rather bulky code changes in this commit are just arranging to pass PlannerInfo around to all the GEQO functions (many of which formerly didn't receive it). Andres Freund, with some editorialization by Tom
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* geqo.h
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* prototypes for various files in optimizer/geqo
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*
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* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/optimizer/geqo.h,v 1.45 2009/07/16 20:55:44 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/* contributed by:
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=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
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* Martin Utesch * Institute of Automatic Control *
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= = University of Mining and Technology =
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* utesch@aut.tu-freiberg.de * Freiberg, Germany *
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=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
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*/
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#ifndef GEQO_H
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#define GEQO_H
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#include "nodes/relation.h"
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#include "optimizer/geqo_gene.h"
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/* GEQO debug flag */
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/*
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#define GEQO_DEBUG
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*/
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/* recombination mechanism */
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/*
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#define ERX
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#define PMX
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#define CX
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#define PX
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#define OX1
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#define OX2
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*/
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#define ERX
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/*
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* Configuration options
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*
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* If you change these, update backend/utils/misc/postgresql.conf.sample
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*/
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extern int Geqo_effort; /* 1 .. 10, knob for adjustment of defaults */
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#define DEFAULT_GEQO_EFFORT 5
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#define MIN_GEQO_EFFORT 1
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#define MAX_GEQO_EFFORT 10
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extern int Geqo_pool_size; /* 2 .. inf, or 0 to use default */
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extern int Geqo_generations; /* 1 .. inf, or 0 to use default */
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extern double Geqo_selection_bias;
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#define DEFAULT_GEQO_SELECTION_BIAS 2.0
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#define MIN_GEQO_SELECTION_BIAS 1.5
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#define MAX_GEQO_SELECTION_BIAS 2.0
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extern double Geqo_seed; /* 0 .. 1 */
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/*
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* Private state for a GEQO run --- accessible via root->join_search_private
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*/
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typedef struct
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{
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List *initial_rels; /* the base relations we are joining */
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unsigned short random_state[3]; /* state for erand48() */
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} GeqoPrivateData;
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/* routines in geqo_main.c */
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extern RelOptInfo *geqo(PlannerInfo *root,
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int number_of_rels, List *initial_rels);
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/* routines in geqo_eval.c */
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extern Cost geqo_eval(PlannerInfo *root, Gene *tour, int num_gene);
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extern RelOptInfo *gimme_tree(PlannerInfo *root, Gene *tour, int num_gene);
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#endif /* GEQO_H */
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