Poor performance on a simple join
От | CS DBA |
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Тема | Poor performance on a simple join |
Дата | |
Msg-id | 4EB1A63E.80101@consistentstate.com обсуждение исходный текст |
Ответы |
Re: Poor performance on a simple join
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Список | pgsql-performance |
Hi All; The below contab2 table conmtains ~400,000 rows. This query should not take this long. We've tweaked work_mem up to 50MB, ensured that the appropriate indexes are in place, etc... Thoughts? Thanks in advance Explain analyze: SELECT contab2.contacts_tab FROM contab2 INNER JOIN sctab ON sctab.id = contab2.to_service_id AND sctab.type IN ('FService', 'FqService', 'LService', 'TService') WHERE contab2.from_contact_id=402513; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------------------------------- Hash Join (cost=16904.28..25004.54 rows=26852 width=4) (actual time=302.621..371.599 rows=12384 loops=1) Hash Cond: (contab2.to_service_id = sctab.id) -> Bitmap Heap Scan on contab2 (cost=1036.49..8566.14 rows=26852 width=20) (actual time=5.191..32.701 rows=26963 loops=1) Recheck Cond: (from_contact_id = 402513) -> Bitmap Index Scan on index_contab2_on_from_user_id (cost=0.00..1029.78 rows=26852 width=0) (actual time=4.779..4.779 rows=26963 loops=1) Index Cond: (from_contact_id = 402513) -> Hash (cost=14445.19..14445.19 rows=113808 width=16) (actual time=297.332..297.332 rows=129945 loops=1) Buckets: 16384 Batches: 1 Memory Usage: 6092kB -> Bitmap Heap Scan on sctab (cost=2447.07..14445.19 rows=113808 width=16) (actual time=29.480..187.166 rows=129945 loops=1) Recheck Cond: ((type)::text = ANY ('{FService,FqService,LService,TService}'::text[])) -> Bitmap Index Scan on index_sctab_on_type (cost=0.00..2418.62 rows=113808 width=0) (actual time=27.713..27.713 rows=130376 loops=1) Index Cond: ((type)::text = ANY ('{FService,FqService,LService,TService}'::text[])) Total runtime: 382.514 ms (13 rows) -- --------------------------------------------- Kevin Kempter - Constent State A PostgreSQL Professional Services Company www.consistentstate.com ---------------------------------------------
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