Re: Relation extension scalability

On Tue, Apr 5, 2016 at 1:05 PM, Peter Geoghegan <pg@heroku.com> wrote:
> On Tue, Apr 5, 2016 at 10:02 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> So the first thing here is that the patch seems to be a clear win in
>> this test.  For a single copy, it seems to be pretty much a wash.
>> When running 4 copies in parallel, it is about 20-25% faster with both
>> logged and unlogged tables.  The second thing that is interesting is
>> that we are getting super-linear scalability even without the patch:
>> if 1 copy takes 20 seconds, you might expect 4 to take 80 seconds, but
>> it really takes 60 unpatched or 45 patched.  If 1 copy takes 30
>> seconds, you might expect 4 to take 120 seconds, but in really takes
>> 105 unpatched or 80 patched.  So we're not actually I/O constrained on
>> this test, I think, perhaps because this machine has an SSD.
>
> It's not unusual for COPY to not be I/O constrained, I believe.

Yeah.  I've committed the patch now, with some cosmetic cleanup.

-- 
Robert Haas
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