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@2ndQuadrant.com   www.2ndQuadrant.us