Re: [HACKERS] Overhead for stats_command_string et al, take 2

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: PostgreSQL-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: [HACKERS] Overhead for stats_command_string et al, take 2
Date: 2006-06-26 18:16:23
Message-ID: 14945.1151345783@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-patches

I wrote:
> IIRC, newer BSDen use a kernel call for this, so you should be able to
> measure it on your own machine. Just tweak ps_status.c to force it to
> select PS_USE_NONE instead of PS_USE_SETPROCTITLE to generate a
> comparison case. I'll try it on my old HPUX box too.

On HPUX, I get a median time of 5.59 sec for CVS HEAD vs 5.36 sec with
ps_status diked out, for the test case of 10000 "SELECT 1;" as separate
transactions, assert-disabled build. So, almost 10% overhead. Given
that the transactions can't get any more trivial than this, that's about
a worst-case number. Not sure if it's worth worrying about or not.
However Kris Kennaway's report a couple weeks ago suggested things might
be worse on BSD.

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Simon Riggs 2006-06-26 18:17:35 Re: "Truncated" tuples for tuple hash tables
Previous Message Jim C. Nasby 2006-06-26 18:14:38 Re: vacuum, performance, and MVCC

Browse pgsql-patches by date

  From Date Subject
Next Message Alvaro Herrera 2006-06-26 18:21:07 Re: [PATCHES] Non-transactional pg_class, try 2
Previous Message Alvaro Herrera 2006-06-26 17:58:23 Re: [PATCHES] Non-transactional pg_class, try 2