Re: shared_buffer - PostgreSQL 9.2

[Keith <keith@xxxxxxxxxxx>]

On Fri, May 13, 2016 at 12:13 AM, Lucas Possamai <drum.lucas@xxxxxxxxx> wrote:

Hi guys,

I currently have a master Postgres server with 128GB RAM.

the shared_buffer is now = 51GB

I read that I should decreased it to something about 32GB

But, I don't wanna have IO issues, that's why the shared_buffer is too high.

Am I going to have IO issues if decrease it?

Cheers

Lucas

All depends on how much of shared_buffers is in high demand. You can use the pg_buffercache contrib module to see about how efficiently shared_buffers is being used. Be aware that running the query against the buffercache view can cause a slight performance hit since it briefly locks shared_buffers to see what's there. Wrote some blog posts about how to do this.

https://www.keithf4.com/a-large-database-does-not-mean-large-shared_buffers/
https://www.keithf4.com/a-small-database-does-not-mean-small-shared_buffers/