Re: Speedier count(*)

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От Tino Wildenhain
Тема Re: Speedier count(*)
Дата
Msg-id 1123745049.27613.1.camel@Andrea.peacock.de
обсуждение исходный текст
Ответ на Re: Speedier count(*)  (Mark Cotner <mcotner@yahoo.com>)
Ответы Re: Speedier count(*)  (Gavin Sherry <swm@alcove.com.au>)
Список pgsql-performance
Am Donnerstag, den 11.08.2005, 00:40 -0400 schrieb Mark Cotner:
> Here's a trigger I wrote to perform essentially the same purpose.  The nice
> thing about this is it keeps the number up to date for you, but you do incur
> slight overhead.
...
>
> CREATE TRIGGER del_rowcount_tr BEFORE DELETE ON test FOR EACH ROW EXECUTE
>    PROCEDURE del_rowcount();
> CREATE TRIGGER add_rowcount_tr BEFORE INSERT ON test FOR EACH ROW EXECUTE
>    PROCEDURE add_rowcount();
>
> INSERT INTO rowcount (tablename) VALUES ('test');
...

beware of problems with concurrency and even what happens
if transactions roll back. Maybe you can "fix" it a bit
by regulary correcting the count via cronjob or so.


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