Re: [HACKERS] psql nested queries with 2000+ records
От | Coronach |
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Тема | Re: [HACKERS] psql nested queries with 2000+ records |
Дата | |
Msg-id | 3.0.5.32.19980321123108.007f14f0@diety.conclave.org обсуждение исходный текст |
Ответ на | Re: [HACKERS] psql nested queries with 2000+ records (Bruce Momjian <maillist@candle.pha.pa.us>) |
Ответы |
Re: [HACKERS] psql nested queries with 2000+ records
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Список | pgsql-hackers |
At 09:54 AM 3/21/98 -0500, Bruce Momjian wrote: >Try it without the LIKE, with just an equals. amusements=> explain select name from games where name in (select name from game s where mfr = ''); NOTICE: QUERY PLAN: Seq Scan on games (cost=207.95 size=446 width=12) SubPlan -> Seq Scan on games (cost=207.95 size=1 width=12) EXPLAIN -- amusements=> explain select name from games where name in (select name from game s2 where mfr = ''); NOTICE: QUERY PLAN: Seq Scan on games (cost=207.95 size=446 width=12) SubPlan -> Seq Scan on games2 (cost=10.23 size=1 width=12) EXPLAIN The first query approved to be lengthy, but the last query was executed and returned rows in just a few. I then did an explain on a query that refered to the games table within the sub query. amusements=> explain select name from games where name in (select name from game s where mfr = ''); NOTICE: QUERY PLAN: Seq Scan on games (cost=207.95 size=446 width=12) SubPlan -> Seq Scan on games (cost=207.95 size=1 width=12) EXPLAIN For the nature of the searches that the front end send to postgres (the database is used with a web interface), it is nec. to use the like expression. Where should I go from here? Thanks once again, -Coronach@hill-b-073.resnet.purdue.edu
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