繼續分析

/** final_cost_hashjoin* Final estimate of the cost and result size of a hashjoin path.** Note: the numbatches estimate is also saved into 'path' for use later** 'path' is already filled in except for the rows and cost fields and* num_batches* 'workspace' is the result from initial_cost_hashjoin* 'sjinfo' is extra info about the join for selectivity estimation* 'semifactors' contains valid data if path->jointype is SEMI or ANTI*/ void final_cost_hashjoin(PlannerInfo *root, HashPath *path,JoinCostWorkspace *workspace,SpecialJoinInfo *sjinfo,SemiAntiJoinFactors *semifactors) {Path *outer_path = path->jpath.outerjoinpath;Path *inner_path = path->jpath.innerjoinpath;double outer_path_rows = outer_path->rows;double inner_path_rows = inner_path->rows;List *hashclauses = path->path_hashclauses;Cost startup_cost = workspace->startup_cost;Cost run_cost = workspace->run_cost;int numbuckets = workspace->numbuckets;int numbatches = workspace->numbatches;Cost cpu_per_tuple;QualCost hash_qual_cost;QualCost qp_qual_cost;double hashjointuples;double virtualbuckets;Selectivity innerbucketsize;ListCell *hcl;

...
qp_qual_cost.startup -= hash_qual_cost.startup;
qp_qual_cost.per_tuple -= hash_qual_cost.per_tuple;
...
}

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轉載于:https://www.cnblogs.com/gaojian/archive/2013/06/14/3134431.html

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