Re: Solaris shared_buffers anomaly? - Mailing list pgsql-performance

Jim C. Nasby wrote:
> On Tue, Jun 13, 2006 at 03:21:34PM -0700, Mischa Sandberg wrote:
>> Raised shared_buffers to 16000 (128MB).
>> DB server dropped to a CRAWL.
>>
>> vmstat showed that it was swapping like crazy.
>> Dropped shared_buffers back down again.
>> Swapping stopped.
>
> What's sort_mem set to? I suspect you simply ran the machine out of
> memory.

8192 (8MB). No issue when shared_buffers was 2000; same apps always.

> Also, Solaris by default will only use a portion of memory for
> filesystem caching, which will kill PostgreSQL performance.

Yep, tested /etc/system segmap_percent at 20,40,60.
No significant difference between 20 and 60.
Default is 10%? 12%? Can't recall.

Was not changed from 20 during the shared_buffer test.
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