Re: 9.4 regression

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?

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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