Re: SLRU statistics
От | Tomas Vondra |
---|---|
Тема | Re: SLRU statistics |
Дата | |
Msg-id | 20200120163754.mbbkbhzaummlo47c@development обсуждение исходный текст |
Ответ на | RE: SLRU statistics ("tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>) |
Ответы |
Re: SLRU statistics
RE: SLRU statistics Re: SLRU statistics |
Список | pgsql-hackers |
On Mon, Jan 20, 2020 at 01:04:33AM +0000, tsunakawa.takay@fujitsu.com wrote: >From: Tomas Vondra <tomas.vondra@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. > >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 think it's unclear how desirable / necessary it is to allow users to tweak those caches. I don't think we should have a GUC for everything, but maybe there's some sort of heuristics to determine the size. The assumption is we actually find practical workloads where the size of these SLRUs is a performance issue. regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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