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Re: ALTER TABLE ADD FOREIGN KEY to partitioned table, is not parallelized

Frédéric Yhuel <frederic.yhuel@dalibo.com>

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From: Frédéric Yhuel <frederic.yhuel@dalibo.com>
To: Dimitrios Apostolou <jimis@gmx.net>
Cc: pgsql-performance@lists.postgresql.org, bruce@momjian.us, Christophe Courtois <christophe.courtois@dalibo.com>
Date: 2025-06-05T14:51:05Z
Lists: pgsql-performance 

On 6/5/25 16:13, Frédéric Yhuel wrote:
> 
> 
> On 6/4/25 16:12, Dimitrios Apostolou wrote:
>> In general I have noticed most operations are slower after a succesful 
>> pg_restore until VACUUM is complete, which is unfortunate as the 
>> database is huge and it takes days to run. Something I have on my list 
>> to try, is whether a COPY FREEZE would alleviate all this trouble, 
>> since all tuples are immediately visible then. Maybe a patch for a new 
>> pg_restore option --freeze is a better solution. Are my assumptions 
>> right?
> 
> It seems that the idea has already been discussed: https:// 
> www.postgresql.org/message-id/flat/ 
> CA%2BU5nM%2BXvkUu9ran%2B5cY%3DTWQquLTpvzte4KVMK%3DaDfbr- 
> xfNXA%40mail.gmail.com#b61a7fee06e10e61afa68712bc0b3c5b
> 
> I've CCed Bruce Mojman, in the hope that he can tell us more about it.
> 
> 

(It might be more interesting now than 12 years ago thanks to this 
patch: 
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=7db0cd2145f2bce84cac92402e205e4d2b045bf2)

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Set PD_ALL_VISIBLE and visibility map bits in COPY FREEZE