Re: Re :Solaris Performance

Tom Lane wrote:
> Mark kirkwood <markir@slingshot.co.nz> writes:
> > The problem area I have experienced is that queries that require a
> > reasonable sort at some point of the plan (e.g have a GROUP BY) will
> > consume all one 1 cpu (box had 2 of them) for a _very_ long time (e.g.
> > 30 minutes - using either compiler) whereas the same query on a (single
> > cpu) Intel/Linux takes about 1 minute.
>
> [ scratches head ... ]  I didn't think there was anything particularly
> system-dependent about the sorting code.  Have you tried profiling, or
> anything to determine where the Solaris version is spending its time?

The only thing I can think of that would affect the sorting code is
paging to swap during the sort.  But the default sort batch size is
512k, so it is hard to imagine it is paging out at that size.  You would
think it would affect normal backend operation, but maybe not.  Does
Solaris have a working-set concept where it will force to swap even if
no one else is using memory?  When I used VMS, we had that problem where
a process would only use a small amount of memory and force to swap even
though no one else was using the machine.  I just looked through my
Mauro Solaris internals book and I don't see any mention of working set
memory usage.

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