| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Cc: | Peter Geoghegan <pg(at)heroku(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Bruce Momjian <bruce(at)momjian(dot)us>, Magnus Hagander <magnus(at)hagander(dot)net>, Andrew Dunstan <andrew(at)dunslane(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com>, Claudio Freire <klaussfreire(at)gmail(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers |
| Date: | 2014-05-07 20:48:18 |
| Message-ID: | 536A9C12.7010406@agliodbs.com |
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| Lists: | pgsql-hackers |
On 05/07/2014 01:36 PM, Jeff Janes wrote:
> On Wed, May 7, 2014 at 11:04 AM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
>> Unfortunately nobody has the time/resources to do the kind of testing
>> required for a new recommendation for shared_buffers.
> I think it is worse than that. I don't think we know what such testing
> would even look like. SSD? BBU? max_connections=20000 with 256 cores?
> pgbench -N? capture and replay of Amazon's workload?
>
> If we could spell out/agree upon what kind of testing we would find
> convincing, that would probably go a long way to getting some people to
> work on carrying out the tests. Unless the conclusion was "please have 3TB
> or RAM and a 50 disk RAID", then there might be few takers.
Well, step #1 would be writing some easy-to-run benchmarks which carry
out selected workloads and measure response times. The minimum starting
set would include one OLTP/Web benchmark, and one DW benchmark.
I'm not talking about the software to run the workload; we have that, in
several varieties. I'm talking about the actual database generator and
queries to run. That's the hard work.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
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