Re: [HACKERS] JOIN between three *simple* tables ...
| От | Tom Lane |
|---|---|
| Тема | Re: [HACKERS] JOIN between three *simple* tables ... |
| Дата | |
| Msg-id | 8775.1013030073@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | JOIN between three *simple* tables ... ("Marc G. Fournier" <scrappy@hub.org>) |
| Ответы |
Re: [HACKERS] JOIN between three *simple* tables ...
|
| Список | pgsql-sql |
"Marc G. Fournier" <scrappy@hub.org> writes:
> iwantu=# \d poc_uid
> Index "poc_uid"
> Column | Type
> --------+--------
> uid | bigint
> btree
> iwantu=# explain select count(1) from orientation_c poc where uid = 1;
> NOTICE: QUERY PLAN:
> Aggregate (cost=2264.97..2264.97 rows=1 width=0)
> -> Seq Scan on orientation_c poc (cost=0.00..2264.96 rows=1 width=0)
> EXPLAIN
You're forgetting ye olde constant-casting problem. You need something
like
select count(1) from orientation_c poc where uid = 1::bigint;
to use an index on a bigint column.
Not sure about the other thing; have you VACUUM ANALYZEd (or at least
ANALYZEd) since filling the tables? It looks like the system thinks
the tables are much smaller than they really are.
regards, tom lane
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