Re: 9.4 regression

On 7 August 2013 17:49, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2013-08-07 17:21:01 +0100, Thom Brown wrote:
>> Only build option used was --enable-depend. I did have
>> --enable-cassert for the shorter 5 min benchmarks, but was removed for
>> the 30 min tests.
>
>> pgbench -j 80 -c 80 -T 300:
>>
>> 8.4 - 535.990042
>> 9.2 - 820.798141
>> 9.3 - 828.395498
>> 9.4 - 197.851720
> e>
>> pgbench -j 80 -c 80 -T 1800:
>>
>> 8.4: 812.482108
>> 9.4 HEAD: 355.397658
>> 9.4 e5592c (9th July): 356.485625
>> 9.4 537227 (7th July): 365.992518
>> 9.4 9b2543 (7th July): 362.587339
>> 9.4 269e78 (5th July): 359.439143
>> 9.4 8800d8 (5th July): 821.933082
>> 9.4 568d41 (2nd July): 822.991160
>
> The differences between those runs look to small for enable/disable
> cassert to me. Are you you properly rebuilt for that?
>
>> 269e78 was the commit immediately after 8800d8, so it appears that
>> introduced the regression.
>>
>> "Use posix_fallocate() for new WAL files, where available."
>
> This is curious. Could you either run a longer test before/after the
> commit or reduce checkpoint_timeout to something like 3min?

Okay, I'll rerun the test for both those commits at 1 hour each with
checkpoint_timeout set at 3mins, but with all other configuration
settings the same

--
Thom