Re: [HACKERS] psql nested queries with 2000+ records
| От | Bruce Momjian |
|---|---|
| Тема | Re: [HACKERS] psql nested queries with 2000+ records |
| Дата | |
| Msg-id | 199803220317.WAA01526@candle.pha.pa.us обсуждение исходный текст |
| Ответ на | Re: [HACKERS] psql nested queries with 2000+ records (Coronach <coronach@hill-b-073.resnet.purdue.edu>) |
| Ответы |
Re: [HACKERS] psql nested queries with 2000+ records
|
| Список | pgsql-hackers |
What does this show in explain? Does it use an index?
select name from games where mfr = ''
>
> 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
I ran this test:
test=> explain select * from pg_proc where oid in (select oid from
pg_proc where oid =3);
NOTICE: QUERY PLAN:
Seq Scan on pg_proc (cost=48.90 size=91 width=122)
SubPlan
-> Index Scan on pg_proc (cost=2.05 size=1 width=4)
and it used the index in the subquery. Please let us about the above
test.
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