Postgresql 旋转驱动，而且速度很慢。切换到固态驱动器会给您带来巨大的改进。非常感谢！我编辑了我的问题以显示解释（分析、缓冲）。似乎只有索引扫描才起作用，而work_mem设置没有太大影响。 Gather (cost=3378.13..13984524.32 rows

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旋转驱动，而且速度很慢。切换到固态驱动器会给您带来巨大的改进。

非常感谢！我编辑了我的问题以显示

解释（分析、缓冲）

。似乎只有索引扫描才起作用，而work_mem设置没有太大影响。

Gather  (cost=3378.13..13984524.32 rows=50262 width=12) (actual time=144.749..1751127.665 rows=173071 loops=1)
  Workers Planned: 2
  Workers Launched: 2
  ->  Parallel Bitmap Heap Scan on T  (cost=2378.13..13978498.12 rows=20942 width=12) (actual time=154.140..1750873.360 rows=57690 loops=3)
        Recheck Cond: ((w1 = ANY ('{123,555,999}'::integer[])) OR (w2 = ANY ('{123,555,999}'::integer[])))
        Rows Removed by Index Recheck: 20069348
        Filter: (occurences > 1)
        Rows Removed by Filter: 110878
        Heap Blocks: exact=902 lossy=107950
        ->  BitmapOr  (cost=2378.13..2378.13 rows=214069 width=0) (actual time=114.320..114.335 rows=0 loops=1)
              ->  Bitmap Index Scan on tdc_idx_w1  (cost=0.00..1631.03 rows=148439 width=0) (actual time=17.100..17.103 rows=166301 loops=1)
                    Index Cond: (w1 = ANY ('{123,555,999}'::integer[]))
              ->  Bitmap Index Scan on tdc_idx_w2  (cost=0.00..721.96 rows=65630 width=0) (actual time=97.208..97.211 rows=339406 loops=1)
                    Index Cond: (w2 = ANY ('{123,555,999}'::integer[]))
Planning Time: 0.280 ms
JIT:
  Functions: 12
  Options: Inlining true, Optimization true, Expressions true, Deforming true
  Timing: Generation 2.689 ms, Inlining 117.210 ms, Optimization 36.646 ms, Emission 28.227 ms, Total 184.772 ms
Execution Time: 1751571.992 ms

Index Scan using tdc_idx_1 on T  (cost=0.58..61.13 rows=1 width=12) (actual time=88.895..239.394 rows=3 loops=1)
  Index Cond: ((w1 = ANY ('{123,555,999}'::integer[])) AND (w2 = ANY ('{123,555,999}'::integer[])))
  Filter: (occurences > 1)
Planning Time: 51.256 ms
Execution Time: 239.518 ms

HashAggregate  (cost=841679.67..842197.01 rows=51734 width=12) (actual time=1755066.279..1755315.668 rows=173071 loops=1)
  Group Key: T.w1, T.w2, T.occurences
  Batches: 5  Memory Usage: 4145kB  Disk Usage: 6920kB
  ->  Append  (cost=561.79..841291.66 rows=51734 width=12) (actual time=1088.188..1753999.477 rows=173074 loops=1)
        ->  Nested Loop  (cost=561.79..579176.31 rows=35898 width=12) (actual time=1088.181..75981.142 rows=55822 loops=1)
              ->  Values Scan on *VALUES*  (cost=0.00..0.04 rows=3 width=4) (actual time=0.006..0.032 rows=3 loops=1)
              ->  Bitmap Heap Scan on T  (cost=561.79..192939.10 rows=11966 width=12) (actual time=407.806..25231.892 rows=18607 loops=3)
                    Recheck Cond: (w1 = *VALUES*.column1)
                    Filter: (occurences > 1)
                    Rows Removed by Filter: 36826
                    Heap Blocks: exact=10630
                    ->  Bitmap Index Scan on tdc_idx_w1  (cost=0.00..558.80 rows=50963 width=0) (actual time=74.175..74.175 rows=55434 loops=3)
                          Index Cond: (w1 = *VALUES*.column1)
        ->  Nested Loop  (cost=250.51..261339.35 rows=15836 width=12) (actual time=217.234..1677133.291 rows=117252 loops=1)
              ->  Values Scan on *VALUES*_1  (cost=0.00..0.04 rows=3 width=4) (actual time=0.020..0.042 rows=3 loops=1)
              ->  Bitmap Heap Scan on T T_1  (cost=250.51..87060.31 rows=5279 width=12) (actual time=143.454..558815.229 rows=39084 loops=3)
                    Recheck Cond: (w2 = *VALUES*_1.column1)
                    Rows Removed by Index Recheck: 19099252
                    Filter: (occurences > 1)
                    Rows Removed by Filter: 74051
                    Heap Blocks: exact=18304 lossy=311451
                    ->  Bitmap Index Scan on tdc_idx_w2  (cost=0.00..249.19 rows=22482 width=0) (actual time=122.725..122.725 rows=113135 loops=3)
                          Index Cond: (w2 = *VALUES*_1.column1)
Planning Time: 68.676 ms
JIT:
  Functions: 21
  Options: Inlining true, Optimization true, Expressions true, Deforming true
  Timing: Generation 5.749 ms, Inlining 219.374 ms, Optimization 370.011 ms, Emission 360.728 ms, Total 955.862 ms
Execution Time: 1756917.366 ms

Nested Loop  (cost=0.58..77.73 rows=1 width=12) (actual time=130.157..295.939 rows=3 loops=1)
  ->  Values Scan on ""*VALUES*_1""  (cost=0.00..0.04 rows=3 width=4) (actual time=0.005..0.019 rows=3 loops=1)
  ->  Nested Loop  (cost=0.58..25.87 rows=3 width=12) (actual time=54.355..98.622 rows=1 loops=3)
        ->  Values Scan on ""*VALUES*""  (cost=0.00..0.04 rows=3 width=4) (actual time=0.003..0.017 rows=3 loops=3)
        ->  Index Scan using tdc_idx_1 on T  (cost=0.58..8.60 rows=1 width=12) (actual time=32.853..32.855 rows=0 loops=9)
              Index Cond: ((w1 = ""*VALUES*"".column1) AND (w2 = ""*VALUES*_1"".column1))
              Filter: (occurences > 1)
Planning Time: 59.447 ms
Execution Time: 296.042 ms

HashAggregate  (cost=3535.61..4052.95 rows=51734 width=12) (actual time=3240.753..3471.160 rows=173071 loops=1)
  Group Key: token_doc_cooccurrences.w1, token_doc_cooccurrences.w2, token_doc_cooccurrences.occurences
  Batches: 1  Memory Usage: 14353kB
  Buffers: shared hit=152549 read=993
  ->  Append  (cost=0.58..3147.60 rows=51734 width=12) (actual time=196.966..2927.069 rows=173074 loops=1)
        Buffers: shared hit=152549 read=993
        ->  Nested Loop  (cost=0.58..1642.71 rows=35898 width=12) (actual time=196.960..1948.256 rows=55822 loops=1)
              Buffers: shared hit=46960 read=533
              ->  Values Scan on ""*VALUES*""  (cost=0.00..0.04 rows=3 width=4) (actual time=0.007..0.024 rows=3 loops=1)
              ->  Index Only Scan using w1_occ_w2 on token_doc_cooccurrences  (cost=0.58..427.90 rows=11966 width=12) (actual time=85.026..603.453 rows=18607 loops=3)
                    Index Cond: ((w1 = ""*VALUES*"".column1) AND (occurences > 1))
                    Heap Fetches: 0
                    Buffers: shared hit=46960 read=533
        ->  Nested Loop  (cost=0.58..728.88 rows=15836 width=12) (actual time=40.764..573.493 rows=117252 loops=1)
              Buffers: shared hit=105589 read=460
              ->  Values Scan on ""*VALUES*_1""  (cost=0.00..0.04 rows=3 width=4) (actual time=0.008..0.027 rows=3 loops=1)
              ->  Index Only Scan using w2_occ_w1 on token_doc_cooccurrences token_doc_cooccurrences_1  (cost=0.58..190.16 rows=5279 width=12) (actual time=30.809..99.922 rows=39084 loops=3)
                    Index Cond: ((w2 = ""*VALUES*_1"".column1) AND (occurences > 1))
                    Heap Fetches: 0
                    Buffers: shared hit=105589 read=460
                    Planning:
  Buffers: shared hit=121 read=13
  Planning Time: 165.009 ms
  Execution Time: 3672.053 ms

Successfully run. Total query runtime: 6 secs 122 msec.
173071 rows affected.

   Rows Removed by Index Recheck: 20069348
   Heap Blocks: exact=902 lossy=107950