Re: select count(*) is slow
| От | aditya desai |
|---|---|
| Тема | Re: select count(*) is slow |
| Дата | |
| Msg-id | CAN0SRDHcVYtpadNDNEk7EHjX6re0UEunG-k1Vxi-ojPA5VK_1Q@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: select count(*) is slow (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: select count(*) is slow
|
| Список | pgsql-performance |
Thanks Tom. Will try with numeric. Please ignore table and index naming.
On Tue, Apr 6, 2021 at 6:55 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
aditya desai <admad123@gmail.com> writes:
> Below query takes 12 seconds. We have an index on postcode.
> select count(*) from table where postcode >= '00420' AND postcode <= '00500'
That query does not match this index:
> CREATE INDEX Table_i1
> ON table USING btree
> ((postcode::numeric));
You could either change postcode to numeric, change all your queries
of this sort to include the cast explicitly, or make an index that
doesn't have a cast.
regards, tom lane
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