Horton

Re: ALTER TABLE .. DETACH PARTITION CONCURRENTLY

Alvaro Herrera <alvherre@2ndquadrant.com>

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From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-08-03T23:51:44Z
Lists: pgsql-hackers 
On 2020-Aug-03, Alvaro Herrera wrote:

> There was a lot of great discussion which ended up in Robert completing
> a much sought implementation of non-blocking ATTACH.  DETACH was
> discussed too because it was a goal initially, but eventually dropped
> from that patch altogether. Nonetheless, that thread provided a lot of
> useful input to this implementation.  Important ones:
> 
> [1] https://postgr.es/m/CA+TgmoYg4x7AH=_QSptvuBKf+3hUdiCa4frPkt+RvXZyjX1n=w@mail.gmail.com
> [2] https://postgr.es/m/CA+TgmoaAjkTibkEr=xJg3ndbRsHHSiYi2SJgX69MVosj=LJmug@mail.gmail.com
> [3] https://postgr.es/m/CA+TgmoY13KQZF-=HNTrt9UYWYx3_oYOQpu9ioNT49jGgiDpUEA@mail.gmail.com

There was some discussion about having a version number in the partition
descriptor somewhere as a means to implement this.  I couldn't figure
out how that would work, or what the version number would be attached
to.  Surely the idea wasn't to increment the version number to every
partition other than the one being detached?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Make detach-partition-concurrently-4 less timing sensitive

  2. Improve documentation on DETACH PARTITION lock levels

  3. Track detached partitions more accurately in partdescs

  4. Allow a partdesc-omitting-partitions to be cached

  5. Fix relcache inconsistency hazard in partition detach

  6. Don't add a redundant constraint when detaching a partition

  7. ALTER TABLE ... DETACH PARTITION ... CONCURRENTLY

  8. Let ALTER TABLE Phase 2 routines manage the relation pointer

  9. Check default partitions constraints while descending