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java-通过保留1亿个数据的联接来提高PostgreSQL查询性能

分类：Postgre SQL作者：编程之家原文地址

我正在使用Postgresql-9.2版本,Windows 7 64位,RAM 6GB.这是一个Java企业项目.

我必须在页面上显示订单相关信息.通过左联接将三个表组合在一起.

表格：

> TV_HD(389772行)
> TV_SNAPSHOT(1564756行)
> TD_MAKKA(419298行)

左联接3个表后,查询给出487252.它也将逐日增加.

enter image description here

表关系：

> TV_HD与TV_SNAPSHOT包含“一对多”关系
> TV_HD与TD_MAKKA包含“一对多”关系

为了更好地理解,我现在使用SQL查询提供图片视图

SELECT * FROM tv_hd其中urino = 1630799

enter image description here

SELECT * FROM tv_snapshot其中urino = 1630799

enter image description here

SELECT * FROM td_makka其中urino = 1630799

enter image description here


该查询将在大约90秒内运行.如何改善查询性能？

我也考虑过建立索引.但是据我所知,当我们想从表中获取2％-4％的数据时,实际上就使用了索引.但是就我而言,我需要从这3个表中获取所有数据.

这是查询：

SELECT count(*)
FROM (SELECT HD.URINO
      FROM
        TV_HD HD
        LEFT JOIN TV_SNAPSHOT T ON (HD.URINO = T.URINO AND HD.TCODE = T.TCODE AND T.DELFLG = 0 AND T.SYUBETSU = 1)
        LEFT JOIN TV_SNAPSHOT T_SQ
          ON (HD.URINO = T_SQ.URINO AND HD.SQCODE = T_SQ.TCODE AND T_SQ.DELFLG = 0 AND T_SQ.SYUBETSU = 3)
        LEFT JOIN (SELECT N.URINO
                   FROM
                     TD_MAKKA N
                   WHERE
                     N.UPDATETIME IN (
                       SELECT MIN(NMIN.UPDATETIME)
                       FROM
                         TD_MAKKA NMIN
                       WHERE
                         N.URINO = NMIN.URINO
                         AND
                         NMIN.TORIKESHIFLG <> -1
                     )
                  ) NYUMIN
          ON (HD.URINO = NYUMIN.URINO)
        LEFT JOIN
        (
          SELECT
            NSUM.URINO,
            SUM(COALESCE(NSUM.NYUKIN, 0))                                                             NYUKIN,
            SUM(COALESCE(NSUM.NYUKIN, 0)) + SUM(COALESCE(NSUM.TESU, 0)) + SUM(COALESCE(NSUM.soTA, 0)) SUMNYUKIN
          FROM
            TD_MAKKA NSUM
          GROUP BY
            URINO
        ) NYUSUM
          ON (HD.URINO = NYUSUM.URINO)
        LEFT JOIN
        (
          SELECT N.URINO
          FROM
            TD_MAKKA N
          WHERE
            UPDATETIME = (
              SELECT MAX(UPDATETIME)
              FROM
                TD_MAKKA NMAX
              WHERE
                N.URINO = NMAX.URINO
                AND
                NMAX.TORIKESHIFLG <> -1
            )
        ) NYUMAX
          ON (HD.URINO = NYUMAX.URINO)
      WHERE ((HD.URIBRUI <> '1') OR (HD.URIBRUI = '1' AND T_SQ.NYUKOBEFLG = '-1'))
      ORDER BY
        HD.URINO DESC
     ) COUNT_

这是EXPLAIN ANALYZE的结果

Aggregate  (cost=7246861.21..7246861.22 rows=1 width=0) (actual time=69549.159..69549.159 rows=1 loops=1)
  ->  Merge Left Join  (cost=7240188.92..7242117.36 rows=379508 width=6) (actual time=68602.689..69510.563 rows=487252 loops=1)
        Merge Cond: (hd.urino = n.urino)
        ->  Sort  (cost=3727299.33..3728248.10 rows=379508 width=6) (actual time=62160.072..62557.132 rows=420036 loops=1)
              Sort Key: hd.urino
              Sort Method: external merge  disk: 6984kB
              ->  Hash Right Join  (cost=169264.26..3686940.26 rows=379508 width=6) (actual time=54796.930..60172.248 rows=420036 loops=1)
                    Hash Cond: (n.urino = hd.urino)
                    ->  Seq Scan on td_makka n  (cost=0.00..3511201.36 rows=209673 width=6) (actual time=24.326..4640.020 rows=419143 loops=1)
                          Filter: (SubPlan 1)
                          Rows Removed by Filter: 155
                          SubPlan 1
                            ->  Aggregate  (cost=8.33..8.34 rows=1 width=23) (actual time=0.009..0.009 rows=1 loops=419298)
                                  ->  Index Scan using idx_td_makka on td_makka nmin  (cost=0.00..8.33 rows=1 width=23) (actual time=0.006..0.007 rows=1 loops=419298)
                                        Index Cond: (n.urino = urino)
                                        Filter: (torikeshiflg <> (-1)::numeric)
                                        Rows Removed by Filter: 0
                    ->  Hash  (cost=163037.41..163037.41 rows=379508 width=6) (actual time=54771.078..54771.078 rows=386428 loops=1)
                          Buckets: 4096  Batches: 16  Memory Usage: 737kB
                          ->  Hash Right Join  (cost=75799.55..163037.41 rows=379508 width=6) (actual time=51599.167..54605.901 rows=386428 loops=1)
                                Hash Cond: ((t_sq.urino = hd.urino) AND (t_sq.tcode = hd.sqcode))
                                Filter: ((hd.uribrui <> '1'::bpchar) OR ((hd.uribrui = '1'::bpchar) AND (t_sq.nyukobeflg = (-1)::numeric)))
                                Rows Removed by Filter: 3344
                                ->  Seq Scan on tv_snapshot t_sq  (cost=0.00..73705.42 rows=385577 width=15) (actual time=0.053..2002.953 rows=389983 loops=1)
                                      Filter: ((delflg = 0::numeric) AND (syubetsu = 3::numeric))
                                      Rows Removed by Filter: 1174773
                                ->  Hash  (cost=68048.99..68048.99 rows=389771 width=14) (actual time=51596.055..51596.055 rows=389772 loops=1)
                                      Buckets: 4096  Batches: 16  Memory Usage: 960kB
                                      ->  Hash Right Join  (cost=21125.85..68048.99 rows=389771 width=14) (actual time=579.405..51348.270 rows=389772 loops=1)
                                            Hash Cond: (nyusum.urino = hd.urino)
                                            ->  Subquery Scan on nyusum  (cost=0.00..35839.52 rows=365638 width=6) (actual time=17.435..49996.674 rows=385537 loops=1)
                                                  ->  GroupAggregate  (cost=0.00..32183.14 rows=365638 width=34) (actual time=17.430..49871.702 rows=385537 loops=1)
                                                        ->  Index Scan using idx_td_makka on td_makka nsum  (cost=0.00..21456.76 rows=419345 width=34) (actual time=0.017..48357.702 rows=419298 loops=1)
                                            ->  Hash  (cost=13969.71..13969.71 rows=389771 width=20) (actual time=491.549..491.549 rows=389772 loops=1)
                                                  Buckets: 4096  Batches: 32  Memory Usage: 567kB
                                                  ->  Seq Scan on tv_hd hd  (cost=0.00..13969.71 rows=389771 width=20) (actual time=0.052..242.415 rows=389772 loops=1)
        ->  Sort  (cost=3512889.60..3512894.84 rows=2097 width=6) (actual time=6442.600..6541.728 rows=486359 loops=1)
              Sort Key: n.urino
              Sort Method: external sort  disk: 8600kB
              ->  Seq Scan on td_makka n  (cost=0.00..3512773.90 rows=2097 width=6) (actual time=0.135..4053.116 rows=419143 loops=1)
                    Filter: ((updatetime)::text = (SubPlan 2))
                    Rows Removed by Filter: 155
                    SubPlan 2
                      ->  Aggregate  (cost=8.33..8.34 rows=1 width=23) (actual time=0.008..0.008 rows=1 loops=419298)
                            ->  Index Scan using idx_td_makka on td_makka nmax  (cost=0.00..8.33 rows=1 width=23) (actual time=0.005..0.006 rows=1 loops=419298)
                                  Index Cond: (n.urino = urino)
                                  Filter: (torikeshiflg <> (-1)::numeric)
                                  Rows Removed by Filter: 0
Total runtime: 69575.139 ms

这是解释分析结果的详细信息：

http://explain.depesz.com/s/23Fg

解决方法:

第一步：
您可以删除选择查询中不需要的更多列,因为您只需要计算总行数即可.例如：

select count(*) from ( SELECT
    HD.URINO
FROM
    TV_HD HD
    LEFT JOIN TV_SNAPSHOT T ON (HD.URINO = T.URINO AND HD.TCODE = T.TCODE AND T.DELFLG = 0 AND T.SYUBETSU = 1)
    LEFT JOIN TV_SNAPSHOT T_SQ ON (HD.URINO = T_SQ.URINO AND HD.SQCODE = T_SQ.TCODE AND T_SQ.DELFLG = 0 AND T_SQ.SYUBETSU = 3)
    LEFT JOIN (SELECT
                    N.URINO
            FROM
                TD_MAKKA N
            WHERE
                N.UPDATETIME IN (
                    SELECT
                        MIN (NMIN.UPDATETIME)
                    FROM
                        TD_MAKKA NMIN
                    WHERE
                        N.URINO = NMIN.URINO
                    AND
                        NMIN.TORIKESHIFLG <> -1 
                )
        ) NYUMIN
    ON  (HD.URINO = NYUMIN.URINO) 
            LEFT JOIN
                (
                    SELECT
                        NSUM.URINO
                        ,SUM (COALESCE(NSUM.NYUKIN ,0)) NYUKIN
                        ,SUM (COALESCE(NSUM.NYUKIN ,0)) + SUM (COALESCE(NSUM.TESU ,0)) + SUM (COALESCE(NSUM.soTA ,0)) SUMNYUKIN
                    FROM
                        TD_MAKKA NSUM
                    GROUP BY
                        URINO
                ) NYUSUM
            ON  (HD.URINO = NYUSUM.URINO)
            LEFT JOIN
                (
                    SELECT
                         N.URINO
                    FROM
                        TD_MAKKA N
                    WHERE
                        UPDATETIME = (
                            SELECT
                                MAX (UPDATETIME)
                            FROM
                                TD_MAKKA NMAX
                            WHERE
                                N.URINO = NMAX.URINO
                            AND
                                NMAX.TORIKESHIFLG <> -1 
                        )
               ) NYUMAX
            ON  (HD.URINO = NYUMAX.URINO)
WHERE ( (HD.URIBRUI <> '1') OR ( HD.URIBRUI = '1' AND T_SQ.NYUKOBEFLG = '-1' ) )
 ORDER BY 
 HD.URINO DESC
  ) COUNT_

第二步：
您可以避免左连接对获取行数没有意义.
例如：

select count(*) from ( SELECT
    HD.URINO
FROM
    TV_HD HD
    LEFT JOIN TV_SNAPSHOT T ON (HD.URINO = T.URINO AND HD.TCODE = T.TCODE AND T.DELFLG = 0 AND T.SYUBETSU = 1)
    LEFT JOIN TV_SNAPSHOT T_SQ ON (HD.URINO = T_SQ.URINO AND HD.SQCODE = T_SQ.TCODE AND T_SQ.DELFLG = 0 AND T_SQ.SYUBETSU = 3)
    LEFT JOIN (SELECT
                    N.URINO
            FROM
                TD_MAKKA N
            WHERE
                N.UPDATETIME IN (
                    SELECT
                        MIN (NMIN.UPDATETIME)
                    FROM
                        TD_MAKKA NMIN
                    WHERE
                        N.URINO = NMIN.URINO
                    AND
                        NMIN.TORIKESHIFLG <> -1 
                )
        ) NYUMIN
    ON  (HD.URINO = NYUMIN.URINO) 
            LEFT JOIN
                (
                    SELECT
                         N.URINO
                    FROM
                        TD_MAKKA N
                    WHERE
                        UPDATETIME = (
                            SELECT
                                MAX (UPDATETIME)
                            FROM
                                TD_MAKKA NMAX
                            WHERE
                                N.URINO = NMAX.URINO
                            AND
                                NMAX.TORIKESHIFLG <> -1 
                        )
               ) NYUMAX
            ON  (HD.URINO = NYUMAX.URINO)
WHERE ( (HD.URIBRUI <> '1') OR ( HD.URIBRUI = '1' AND T_SQ.NYUKOBEFLG = '-1' ) )

  ) COUNT_

第三步：您可以使用PgAdmin图形解释计划来分析查询并避免其他不必要的执行开销.

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