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9ee014fc89
Module provides new access method. It is actually a simple Bloom filter implemented as pgsql's index. It could give some benefits on search with large number of columns. Module is a single way to test generic WAL interface committed earlier. Author: Teodor Sigaev, Alexander Korotkov Reviewers: Aleksander Alekseev, Michael Paquier, Jim Nasby
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* blcost.c
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* Cost estimate function for bloom indexes.
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*
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* Copyright (c) 2016, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/bloom/blcost.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "fmgr.h"
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#include "optimizer/cost.h"
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#include "utils/selfuncs.h"
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#include "bloom.h"
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/*
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* Estimate cost of bloom index scan.
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*/
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void
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blcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
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Cost *indexStartupCost, Cost *indexTotalCost,
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Selectivity *indexSelectivity, double *indexCorrelation)
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{
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IndexOptInfo *index = path->indexinfo;
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List *qinfos;
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GenericCosts costs;
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/* Do preliminary analysis of indexquals */
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qinfos = deconstruct_indexquals(path);
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MemSet(&costs, 0, sizeof(costs));
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/* We have to visit all index tuples anyway */
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costs.numIndexTuples = index->tuples;
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/* Use generic estimate */
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genericcostestimate(root, path, loop_count, qinfos, &costs);
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*indexStartupCost = costs.indexStartupCost;
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*indexTotalCost = costs.indexTotalCost;
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*indexSelectivity = costs.indexSelectivity;
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*indexCorrelation = costs.indexCorrelation;
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}
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