Re: Process priority.

It depends what the intended purpose if for. In our scenario, there are a
number of ad-hoc export tasks running during the day that are quite cpu
intensive.

There is a noticeably slow response time when exports are being run. By
lowering the priority of the export postmaster, the system appeared to run
far smoother for standard users.

I guess you could set-up a replication database which I probably will do in
the end, however I just wanted to have a play and see if I could extend
postgres with c. I don't profess to being a c or os guru. Thankyou for your
feedback.

Theo

-----Original Message-----
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Friday, 18 March 2005 11:06 AM
To: Theo Galanakis
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] Process priority.

Theo Galanakis <Theo(dot)Galanakis(at)lonelyplanet(dot)com(dot)au> writes:
> I wrote a C program that can be called through postgres via stored
> procedures. It allows you to change the current postmaster process
> priority.

You are aware that that's widely considered either useless or
counterproductive? Renice-ing one backend seldom gives helpful results,
because (a) what usually matters more than CPU usage is I/O, and renice
doesn't change I/O priorities; (b) priority inversion results in
higher-priority backends blocking behind the low-priority one whenever it's
managed to acquire a lock.

regards, tom lane

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