Re: pgsql: Add EXPLAIN (MEMORY) to report planner memory consumption
От | Justin Pryzby |
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Тема | Re: pgsql: Add EXPLAIN (MEMORY) to report planner memory consumption |
Дата | |
Msg-id | ZcFfeunBiKFGuebP@pryzbyj2023 обсуждение исходный текст |
Ответы |
Re: pgsql: Add EXPLAIN (MEMORY) to report planner memory consumption
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Список | pgsql-hackers |
Up to now, the explain " " (two space) format is not mixed with "=". And, other places which show "Memory" do not use "=". David will remember prior discussions. https://www.postgresql.org/message-id/20200402054120.GC14618@telsasoft.com https://www.postgresql.org/message-id/20200407042521.GH2228@telsasoft.com "Memory: used=%lld bytes allocated=%lld bytes", vs "Buckets: %d (originally %d) Batches: %d (originally %d) Memory Usage:%ldkB\n", There was some discussion about "bytes" - maybe it should instead show kB? (Also, I first thought that "peek" should be "peak", but eventually I realized that's it's as intended.) On Fri, Jan 12, 2024 at 10:53:08PM +0530, Abhijit Menon-Sen wrote: > (Those "bytes" look slightly odd to me in the midst of all the x=y > pieces, but that's probably not worth thinking about.) On Mon, Jan 29, 2024 at 04:55:27PM +0000, Alvaro Herrera wrote: > Add EXPLAIN (MEMORY) to report planner memory consumption > > This adds a new "Memory:" line under the "Planning:" group (which > currently only has "Buffers:") when the MEMORY option is specified. > > In order to make the reporting reasonably accurate, we create a separate > memory context for planner activities, to be used only when this option > is given. The total amount of memory allocated by that context is > reported as "allocated"; we subtract memory in the context's freelists > from that and report that result as "used". We use > MemoryContextStatsInternal() to obtain the quantities. > > The code structure to show buffer usage during planning was not in > amazing shape, so I (Álvaro) modified the patch a bit to clean that up > in passing. > > Author: Ashutosh Bapat > Reviewed-by: David Rowley, Andrey Lepikhov, Jian He, Andy Fan > Discussion: https://www.postgresql.org/message-id/CAExHW5sZA=5LJ_ZPpRO-w09ck8z9p7eaYAqq3Ks9GDfhrxeWBw@mail.gmail.com
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