Problem with collector statistic
От | Marco Aurélio V. da Silva |
---|---|
Тема | Problem with collector statistic |
Дата | |
Msg-id | 010e01c84266$ae0eebd0$0402a8c0@marquinho обсуждение исходный текст |
Ответы |
Re: Problem with collector statistic
Re: Problem with collector statistic |
Список | pgsql-general |
Dears, Running a query on 2 database-equal, with the same indices, but with slightly different data, I have a very different result of performance. In one the index is used to make the join, in another it is seqscan. The next consultation with explain. Select a.CodPagador,b.Descricao From Frete01 a Left Outer Join Frete02 b On (a.CodPagador = b.CodCliente) explain in database bad: "Merge Left Join (cost=46619.72..48113.50 rows=58995 width=39) (actual time=7435.922..8359.063 rows=59161 loops=1)" " Merge Cond: ("outer".codpagador = "inner".codcliente)" " -> Sort (cost=24649.80..24797.29 rows=58995 width=11) (actual time=4063.517..4171.374 rows=59161 loops=1)" " Sort Key: a.codpagador" " -> Seq Scan on frete01 a (cost=0.00..19974.95 rows=58995 width=11) (actual time=9.007..3223.000 rows=59161 loops=1)" " -> Sort (cost=21969.91..22274.37 rows=121784 width=39) (actual time=3372.375..3674.563 rows=169818 loops=1)" " Sort Key: b.codcliente" " -> Seq Scan on frete02 b (cost=0.00..8127.84 rows=121784 width=39) (actual time=17.330..1608.599 rows=121740 loops=1)" "Total runtime: 8448.797 ms" explain in good dabatase: "Limit (cost=0.00..46856.62 rows=55204 width=39) (actual time=11.205..536.761 rows=55204 loops=1)" " -> Nested Loop Left Join (cost=0.00..295237.26 rows=55204 width=39) (actual time=11.201..508.936 rows=55204 loops=1)" " -> Seq Scan on frete01 a (cost=0.00..19974.95 rows=55204 width=11) (actual time=11.057..220.711 rows=55204 loops=1)" " -> Index Scan using frete02_f021 on frete02 b (cost=0.00..4.65 rows=1 width=39) (actual time=0.021..0.024 rows=1 loops=9363)" " Index Cond: ("outer".codpagador = b.codcliente)" "Total runtime: 551.331 ms" Thanks to advance for your´s attention, Marco Aurélio V. da Silva Prodata Inf. e Cad. Ltda. MSN: marco@prodatanet.com.br Fone: (33) 3322-3082
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