In PostgreSQL 14, I have a table with around 10 million of rows with this structure:
CREATE INDEX search_stats_date_idx ON search_stats USING brin (date);
CREATE INDEX search_stats_search_query_idx ON search_stats USING btree (search_query);
CREATE INDEX search_stats_user_id_idx ON search_stats USING btree (user_id);
This is my EXPLAIN (ANALYZE, BUFFERS)
Sort (cost=576930.96..580812.49 rows=1552612 width=68) (actual time=15702.669..15936.775 rows=1656788 loops=1) |
Sort Key: (count(*)) DESC, (count(DISTINCT search_stats.user_id)) DESC |
Sort Method: external merge Disk: 134584kB |
Buffers: shared hit=15953 read=29111, temp read=38184 written=32013 |
-> WindowAgg (cost=100614.65..353591.31 rows=1552612 width=68) (actual time=14207.366..14836.972 rows=1656788 loops=1) |
Buffers: shared hit=15953 read=29111, temp read=21361 written=15188 |
-> GroupAggregate (cost=100614.65..334183.66 rows=1552612 width=60) (actual time=7578.995..13339.283 rows=1656788 loops=1) |
Group Key: search_stats.search_query |
Buffers: shared hit=15953 read=29111 |
-> Gather Merge (cost=100614.65..305804.74 rows=1713707 width=109) (actual time=7578.971..10803.777 rows=1714043 loops=1) |
Workers Planned: 4 |
Workers Launched: 4 |
Buffers: shared hit=15953 read=29111 |
-> Sort (cost=99614.59..100685.65 rows=428426 width=109) (actual time=5440.355..5521.071 rows=342809 loops=5) |
Sort Key: search_stats.search_query |
Sort Method: quicksort Memory: 113434kB |
Buffers: shared hit=15953 read=29111 |
Worker 0: Sort Method: quicksort Memory: 93953kB |
Worker 1: Sort Method: quicksort Memory: 95874kB |
Worker 2: Sort Method: quicksort Memory: 43844kB |
Worker 3: Sort Method: quicksort Memory: 38459kB |
-> Parallel Append (cost=0.00..59538.15 rows=428426 width=109) (actual time=12.168..142.869 rows=342809 loops=5) |
Buffers: shared hit=15785 read=29111 |
-> Parallel Seq Scan on mdr_querystats_part_may search_stats_5 (cost=0.00..8218.54 rows=119279 width=110) (actual time=0.018..87.771 rows=286326 loops=1)|
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2312 read=4117 |
-> Parallel Seq Scan on mdr_querystats_part_jun search_stats_6 (cost=0.00..8212.33 rows=119198 width=110) (actual time=0.018..86.707 rows=286133 loops=1)|
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2272 read=4152 |
-> Parallel Seq Scan on mdr_querystats_part_jul search_stats_7 (cost=0.00..8206.25 rows=1 width=109) (actual time=59.912..59.912 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Rows Removed by Filter: 285960 |
Buffers: shared hit=2270 read=4149 |
-> Parallel Seq Scan on mdr_querystats_part_jan search_stats_1 (cost=0.00..8198.10 rows=118983 width=109) (actual time=0.405..52.659 rows=142808 loops=2)|
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2203 read=4210 |
-> Parallel Seq Scan on mdr_querystats_part_mar search_stats_3 (cost=0.00..8196.36 rows=119000 width=109) (actual time=0.499..21.592 rows=57132 loops=5) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2275 read=4136 |
-> Parallel Seq Scan on mdr_querystats_part_apr search_stats_4 (cost=0.00..8187.51 rows=118877 width=109) (actual time=0.006..45.467 rows=142681 loops=2)|
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2252 read=4152 |
-> Parallel Seq Scan on mdr_querystats_part_feb search_stats_2 (cost=0.00..8176.93 rows=118705 width=109) (actual time=0.061..83.882 rows=284948 loops=1)|
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Buffers: shared hit=2201 read=4195 |
-> Parallel Seq Scan on mdr_querystats_part_aug search_stats_8 (cost=0.00..0.00 rows=1 width=64) (actual time=0.000..0.000 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
-> Parallel Seq Scan on mdr_querystats_part_sep search_stats_9 (cost=0.00..0.00 rows=1 width=64) (actual time=0.001..0.001 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
-> Parallel Seq Scan on mdr_querystats_part_oct search_stats_10 (cost=0.00..0.00 rows=1 width=64) (actual time=0.000..0.000 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
-> Parallel Seq Scan on mdr_querystats_part_nov search_stats_11 (cost=0.00..0.00 rows=1 width=64) (actual time=0.000..0.001 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
-> Parallel Seq Scan on mdr_querystats_part_dec search_stats_12 (cost=0.00..0.00 rows=1 width=64) (actual time=0.002..0.002 rows=0 loops=1) |
Filter: ((search_date >= '2023-01-01 00:00:00'::timestamp without time zone) AND (search_date < '2023-07-01 00:00:00'::timestamp without time zone)) |
Planning: |
Buffers: shared hit=20 |
Planning Time: 0.602 ms |
Execution Time: 16105.124 ms