Re: Using Small Size SSDs to improve performance?

Josh Berkus wrote:
> I haven't been able to test things like putting a "hot" table on a
> specific SSD.
>

Putting a hot table or even better an index on them, where that relation
fits on SSD but the whole database doesn't, can work well. But it
doesn't give the speedup levels people expect because "hot" stuff tends
to already be in memory, too. I've deflated multiple "SSD will fix our
problems!" meetings with output from pg_buffercache, showing everything
they were planning to put on there was already in the hottest part of
database RAM: shared_buffers. Indexes of heavily written tables are
the thing I've seen the most actual improvement on like this.

--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.us