Re: 7.3 vs 7.4 performance - Mailing list pgsql-performance

From Christopher Browne
Subject Re: 7.3 vs 7.4 performance
Date
Msg-id m34qu5mz5c.fsf@wolfe.cbbrowne.com
Whole thread Raw
In response to 7.3 vs 7.4 performance  (Orion Henry <orion@trustcommerce.com>)
List pgsql-performance
In an attempt to throw the authorities off his trail, csmanioto@uol.com.br ("Carlos Eduardo Smanioto") transmitted:
>> I did some heavy-transaction-oriented tests recently on somewhat
>> heftier quad-Xeon hardware, and found little difference between 2.4
>> and 2.6, and a small-but-quite-repeatable advantage with FreeBSD
>> 4.9.  Now, I'm quite sure my load was rather different from yours,
>> but I find the claim of doubling of speed rather surprising.
>
> What's the type of File System you used in the Linux? I am wanting
> to know which is the operational system better for PostgreSQL:
> FreeBSD versus Linux 2.6.

On the Linux box in question, I was using JFS, which has had the mixed
reviews, lately, that on the one hand, it _appears_ to be a tad faster
than all the others, but that has been, on the other hand, associated
with systems hanging up and crashing, under load.

The latter bit is a _really_ big caveat.  On that particular machine,
I have a nicely repeatable "test case" where I can do a particular set
of "system load" that consistently takes the system down, to the point
of having to hit the "big red button."  If I could point to a clear
reason why it happens, I'd be a much happier camper.  As it stands, it
is a bit nebulous whether the problem is:
 a) Hardware drivers,
 b) Flakey hardware (which Linux 2.6.1 copes with a lot better than
    2.4!),
 c) Flakey 2.4 kernel,
 d) Problem with JFS,
 e) Something else not yet identified as a plausible cause.

If I could say, "Oh, it's an identified bug in the Frobozz RAID
controller drivers, and was fixed in 2.6.0-pre-17", that would help
allay the suspicion that the problem could be any of the above.
--
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http://www.ntlug.org/~cbbrowne/
"Another result of the tyranny of Pascal is that beginners don't use
function pointers."  --Rob Pike

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