greenplumn blcost 源码
greenplumn blcost 代码
文件路径：/contrib/bloom/blcost.c
/*-------------------------------------------------------------------------
*
* blcost.c
* Cost estimate function for bloom indexes.
*
* Copyright (c) 2016-2019, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/bloom/blcost.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "fmgr.h"
#include "utils/selfuncs.h"
#include "bloom.h"
/*
* Estimate cost of bloom index scan.
*/
void
blcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
Cost *indexStartupCost, Cost *indexTotalCost,
Selectivity *indexSelectivity, double *indexCorrelation,
double *indexPages)
{
IndexOptInfo *index = path->indexinfo;
GenericCosts costs;
MemSet(&costs, 0, sizeof(costs));
/* We have to visit all index tuples anyway */
costs.numIndexTuples = index->tuples;
/* Use generic estimate */
genericcostestimate(root, path, loop_count, &costs);
*indexStartupCost = costs.indexStartupCost;
*indexTotalCost = costs.indexTotalCost;
*indexSelectivity = costs.indexSelectivity;
*indexCorrelation = costs.indexCorrelation;
*indexPages = costs.numIndexPages;
}
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