Re: [PERFORM] Newbie question: ultra fast count(*)

[Merlin Moncure]

 I have been reading all this technical talk about costs and such that
 I don't (_yet_) understand.
 
 Now I'm scared... what's the fastest way to do an equivalent of
 count(*) on a table to know how many items it has?

Make sure to analyze the database frequently and check pg_class for
reltuples field.  This gives 0 time approximations of # row in table at
the time of the last analyze.

Many other approaches...check archives.  Also your requirements are
probably not as high as you think they are ;)

Merlin


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Re: [PERFORM] Newbie question: ultra fast count(*)

[Jaime Casanova]

On 11/25/05, Rodrigo Madera [EMAIL PROTECTED] wrote:
 I have been reading all this technical talk about costs and such that
 I don't (_yet_) understand.

 Now I'm scared... what's the fastest way to do an equivalent of
 count(*) on a table to know how many items it has?

 Thanks,
 Rodrigo


you really *need* this?

you can do
SELECT reltuples FROM pg_class WHERE relname = 'your_table_name';

but this will give you an estimate... if you want real values you can
make a TRIGGER that maintain a counter in another table

--
regards,
Jaime Casanova
(DBA: DataBase Aniquilator ;)

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