PostgreSQL在何处处理 sql查询之六十六

继续分析

/*

 * 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;
    ...
}