On Tue, Jan 21, 2020 at 05:09:33PM +0900, Masahiko Sawada wrote:
On Tue, 21 Jan 2020 at 01:38, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote:
On Mon, Jan 20, 2020 at 01:04:33AM +0000, tsunakawa.ta...@fujitsu.com wrote:
>From: Tomas Vondra <tomas.von...@2ndquadrant.com>
>> One of the stats I occasionally wanted to know are stats for the SLRU
>> stats (we have couple of those - clog, subtrans, ...). So here is a WIP
>> version of a patch adding that.
+1
>
>How can users take advantage of this information? I think we also need
>the ability to set the size of SLRU buffers. (I want to be freed from
>the concern about the buffer shortage by setting the buffer size to its
>maximum. For example, CLOG would be only 1 GB.)
>
You're right the users can't really take advantage of this - my primary
motivation was providing a feedback for devs, benchmarking etc. That
might have been done with DEBUG messages or something, but this seems
more convenient.
I've not tested the performance impact but perhaps we might want to
disable these counter by default and controlled by a GUC. And similar
to buffer statistics it might be better to inline
pgstat_count_slru_page_xxx function for better performance.
Hmmm, yeah. Inlining seems like a good idea, and maybe we should have
something like track_slru GUC.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
