Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Jordan Hurwich
Awesome, this is really helpful Samed. I'll start experimenting with these settings next. Really appreciate your guidance. On Wed, Dec 14, 2022 at 10:41 AM Samed YILDIRIM wrote: > Hello Jordan, > > You don't have to set %25 for the best performance. You need to test > different values for your d

Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Samed YILDIRIM
Hello Jordan, You don't have to set %25 for the best performance. You need to test different values for your database. If I were you, I would - try to enable huge pages. You probably will see better performance with bigger shared_buffers when you configure huge pages. -> https://www.post

Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Jordan Hurwich
Thanks Tom, that makes a lot of sense. Given we're seeing low iowait and blk_read_time at 4GB shared_buffers, sounds like we should just declare victory here and be happy with that setting? On Wed, Dec 14, 2022 at 10:27 AM Tom Lane wrote: > Jordan Hurwich writes: > > I'm familiar with the artic

Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Tom Lane
Jordan Hurwich writes: > I'm familiar with the article you linked to, and part of my surprise is > that with these 32GB RAM machines we're seeing better performance at 12.5% > (4GB) than the commonly recommended 25% (8GB) of system memory for > shared_buffers. Your notes about disk read stats from

Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Jordan Hurwich
Thanks for your thoughtful response Samed. I'm familiar with the article you linked to, and part of my surprise is that with these 32GB RAM machines we're seeing better performance at 12.5% (4GB) than the commonly recommended 25% (8GB) of system memory for shared_buffers. Your notes about disk rea

Re: Increased iowait and blk_read_time with higher shared_buffers

2022-12-14 Thread Samed YILDIRIM
Hi Jordan, Increased shared buffer size does not necessarily mean an increased performance. Regarding the negative correlation between IOWait and shared_buffers' size; if you don't increase memory of the system, it is an expected result in my opinion. Because, PostgreSQL starts reserving a bigger