| From: | Tino Wildenhain <tino(at)wildenhain(dot)de> |
|---|---|
| To: | Mark Cotner <mcotner(at)yahoo(dot)com> |
| Cc: | Gavin Sherry <swm(at)alcove(dot)com(dot)au>, Dan Harris <fbsd(at)drivefaster(dot)net>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Speedier count(*) |
| Date: | 2005-08-11 07:24:08 |
| Message-ID: | 1123745049.27613.1.camel@Andrea.peacock.de |
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| Thread: | |
| Lists: | 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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