Horton

Re: ALTER TABLE .. DETACH PARTITION CONCURRENTLY

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-04-26T19:44:46Z
Lists: pgsql-hackers

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On 2021-Apr-26, Alvaro Herrera wrote:

> > Please allow me to study the patch a bit more closely and get back tomorrow.
> 
> Sure, thanks!

Here's a more polished version.

After trying the version with the elog(ERROR) when two detached
partitions are present, I decided against it; it is unhelpful because
it doesn't let you build partition descriptors for anything.  So I made
it an elog(WARNING) (not an ereport, note), and keep the most recent
pg_inherits.xmin value.  This is not great, but it lets you out of the
situation by finalizing one of the detaches.

The other check (at ALTER TABLE .. DETACH time) is an ereport(ERROR) and
should make the first one unreachable.

-- 
Álvaro Herrera                            39°49'30"S 73°17'W

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