| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | David Teran <david(dot)teran(at)cluster9(dot)com> |
| Cc: | Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com>, PgSQL Performance ML <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: another query optimization question |
| Date: | 2004-01-30 22:40:29 |
| Message-ID: | 20419.1075502429@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
David Teran <david(dot)teran(at)cluster9(dot)com> writes:
>> I recall that we saw similar symptoms once before, and I thought we'd
>> fixed it, but I didn't find any relevant mentions in the CVS logs.
>>
>> What version are you running, exactly?
> 7.4.1, build from sourcecode. Running on MacOS X Server 10.3.2, dual G5
> with 3.5 GB RAM
Interesting. I have recollected where we saw this before:
http://archives.postgresql.org/pgsql-hackers/2003-11/msg01528.php
Apparently gettimeofday() has a glitch on some BSD releases. OS X is
a BSD derivative and it's not so surprising if it has it too.
May I suggest that you try the test program given here:
http://archives.postgresql.org/pgsql-hackers/2003-11/msg01546.php
and file a bug report with Apple if it shows any out-of-order results?
I am fairly certain that I tried that test program when I devised it
on my own OS X machine, and couldn't get a failure. Maybe it depends
on your hardware (hm, could dual CPUs be the key factor)?
regards, tom lane
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