Re: [HACKERS] large regression for parallel COPY

On 2016-04-05 17:12:11 -0400, Robert Haas wrote: > On Wed, Mar 30, 2016 at 4:10 PM, Andres Freund wrote: > > Indeed. On SSDs I see about a 25-35% gain, on HDDs about 5%. If I > > increase the size of backend_flush_after to 64 (like it's for bgwriter) > > I however do get about

Re: [HACKERS] large regression for parallel COPY

Hello Robert, I tried the same test mentioned in the original post on cthulhu (EDB machine, CentOS 7.2, 8 sockets, 8 cores per socket, 2 threads per core, Xeon E7-8830 @ 2.13 GHz). I attempted to test both the effects of multi_extend_v21 and the *_flush_after settings. I'm not sure of

Re: [HACKERS] large regression for parallel COPY

On Wed, Mar 30, 2016 at 4:10 PM, Andres Freund wrote: > Indeed. On SSDs I see about a 25-35% gain, on HDDs about 5%. If I > increase the size of backend_flush_after to 64 (like it's for bgwriter) > I however do get about 15% for HDDs as well. I tried the same test mentioned

Re: [HACKERS] large regression for parallel COPY

On 03/30/2016 01:10 PM, Andres Freund wrote: On 2016-03-30 15:50:21 -0400, Robert Haas wrote: On Thu, Mar 10, 2016 at 8:29 PM, Andres Freund wrote: Allow to trigger kernel writeback after a configurable number of writes. While testing out Dilip Kumar's relation extension

Re: [HACKERS] large regression for parallel COPY

On 2016-03-30 15:50:21 -0400, Robert Haas wrote: > On Thu, Mar 10, 2016 at 8:29 PM, Andres Freund wrote: > > Allow to trigger kernel writeback after a configurable number of writes. > > While testing out Dilip Kumar's relation extension patch today, I > discovered (with some

[HACKERS] large regression for parallel COPY

On Thu, Mar 10, 2016 at 8:29 PM, Andres Freund wrote: > Allow to trigger kernel writeback after a configurable number of writes. While testing out Dilip Kumar's relation extension patch today, I discovered (with some help from Andres) that this causes nasty regressions when