Re: Postgresql on SUN Server

On Tue, May 27, 2003 at 12:07:06PM -0600, scott.marlowe wrote:
> I wonder if that's a performance issue with Solaris and shared memory that
> isn't a problem with BSD or Linux on Sparc Hardware?

I wonder that, also. I haven't had a chance to try it out.

The problem in our case is that we couldn't use Linux or BSD anyway,
because we need the 8- and 10-way scalability we have, and we need
the cleverness about disabling processors, &c., that's built into
Solaris. So even if Solaris is the problem, we're stuck.

The file system buffers, on the other hand, are pretty fast, so it's
not too big a penalty.

One thing that is very interesting about all of this is that the
large shared buffers only exact their performance penalty over time.
My hypothesis is that it has something to do with expiring buffers.
In one test I performed, I set the buffer to 1G. I then did a bunch
of work on a data set that was close to 1G. Speedy. But when I
finally went over 1G, everything slowed to a crawl. This makes me
believe that the problem is in the way records are added to or
expired from the buffer.

It was only one test, mind: I didn't have time to repeat it. So it's
just a bit of gossip and not a result.

A

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