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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
31 lines
1015 B
C
31 lines
1015 B
C
/*-------------------------------------------------------------------------
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*
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* geqo_mutation.h
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* prototypes for mutation functions 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_mutation.h,v 1.22 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_MUTATION_H
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#define GEQO_MUTATION_H
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#include "optimizer/geqo.h"
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extern void geqo_mutation(PlannerInfo *root, Gene *tour, int num_gene);
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#endif /* GEQO_MUTATION_H */
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