Re: Need advice about triggers - Mailing list pgsql-performance

From Hannu Krosing
Subject Re: Need advice about triggers
Date
Msg-id 1063120683.6150.43.camel@fuji.krosing.net
Whole thread Raw
In response to Need advice about triggers  ("Mindaugas Riauba" <mind@bi.lt>)
List pgsql-performance
Mindaugas Riauba kirjutas T, 09.09.2003 kell 15:40:
>   Hello,
>
>   I have small table (up to 10000 rows) and every row will be updated
> once per minute. Table also has "before update on each row" trigger
> written in plpgsql. But trigger 99.99% of the time will do nothing
> to the database. It will just compare old and new values in the row
> and those values almost always will be identical.
>
>   Now I tried simple test and was able to do 10000 updates on 1000
> rows table in ~30s. That's practically enough but I'd like to have
> more room to slow down.

Is it 10000 *rows* or 10000*1000 = 10 000 000 *rows* updated ?

When I run a simple update 10 times on 1000 rows (with no trigger, which
you claim to take about the same time) it took 0.25 sec.

> Also best result I achieved by doing commit+vacuum every ~500
> updates.

It seems like you are updating more than one row at each update ?

---------------
Hannu


pgsql-performance by date:

Previous
From: Richard Huxton
Date:
Subject: Re: Need advice about triggers
Next
From: Vivek Khera
Date:
Subject: Re: increase performancr with "noatime"?