On 12/8/18 6:38 PM, Andres Freund wrote:
On 2018-12-08 15:23:19 -0800, Rob Sargent wrote:
On Dec 8, 2018, at 3:12 PM, Andres Freund <andres@xxxxxxxxxxx> wrote:
On 2018-12-08 12:06:23 -0800, Jeremy Schneider wrote:
On RDS PostgreSQL, the default is 25% of your server memory. This seems
to be pretty widely accepted as a good starting point on PostgreSQL.
FWIW, I think it's widely cited, but also bad advice. 25% for a OLTP
workload on a 1TB machine with a database size above 25% is a terrible
idea.
Sorry, could you please expand “database size above 25%”? 25% of what?
Memory available to postgres (i.e. 100% of the server's memory on a
server dedicated to postgres, less if it's shared duty).
I think the best advice these days is that you need to triangulate to
find the best setting for shared_buffers. It's very workload dependent,
and there isn't even a semi-reliable rule of thumb.
cheers
andrew
--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
