Re: benchmarking the query planner - Mailing list pgsql-hackers

From Tom Lane
Subject Re: benchmarking the query planner
Date
Msg-id 5823.1229094527@sss.pgh.pa.us
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In response to Re: benchmarking the query planner  ("Greg Stark" <stark@enterprisedb.com>)
List pgsql-hackers
"Greg Stark" <stark@enterprisedb.com> writes:
> On Fri, Dec 12, 2008 at 2:35 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> But having said that, I have wondered whether we should consider
>> allowing the sample to grow to fill maintenance_work_mem

> Hm, so I wonder what this does to the time analyze takes. I think it
> would be the only thing where raising maintenance_work_mem would
> actually increase the amount of time an operation takes. Generally
> people raise it to speed up index builds and vacuums etc.

Yeah --- we might need to make it a separate GUC knob instead of tying
it directly to maintenance_work_mem.  But still, is *any* fixed-size
sample really going to help much for large tables?
        regards, tom lane


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