Horton

Re: Memory consumed by child SpecialJoinInfo in partitionwise join planning

Andrei Lepikhov <a.lepikhov@postgrespro.ru>

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From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
To: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, vignesh C <vignesh21@gmail.com>
Cc: Amit Langote <amitlangote09@gmail.com>, Richard Guo <guofenglinux@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2024-02-14T04:19:59Z
Lists: pgsql-hackers 
On 30/1/2024 12:44, Ashutosh Bapat wrote:
> Thanks Vignesh. PFA patches rebased on the latest HEAD. The patch
> addressing Amit's comments is still a separate patch for him to
> review.
Thanks for this improvement. Working with partitions, I frequently see 
peaks of memory consumption during planning. So, maybe one more case can 
be resolved here.
Patch 0001 looks good. I'm not sure about free_child_sjinfo_members. Do 
we really need it as a separate routine? It might be better to inline 
this code.
Patch 0002 adds valuable comments, and I'm OK with that.

Also, as I remember, some extensions, such as pg_hint_plan, call 
build_child_join_sjinfo. It is OK to break the interface with a major 
version. But what if they need child_sjinfo a bit longer and collect 
links to this structure? I don't think it is a real stopper, but it is 
worth additional analysis.

-- 
regards,
Andrei Lepikhov
Postgres Professional

Commits

  1. Code review for 6190d828cd2

  2. Do not translate dummy SpecialJoinInfos for child joins

  3. Reduce memory used by partitionwise joins

  4. Remove dummy_spinlock