Horton

Re: ALTER TABLE .. DETACH PARTITION CONCURRENTLY

Pavel Luzanov <p.luzanov@postgrespro.ru>

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From: Pavel Luzanov <p.luzanov@postgrespro.ru>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Álvaro Herrera <alvherre@alvh.no-ip.org>, Justin Pryzby <pryzby@telsasoft.com>, Tom Lane <tgl@sss.pgh.pa.us>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2021-05-06T11:22:56Z
Lists: pgsql-hackers 
On 06.05.2021 08:35, Amit Langote wrote:
> On Wed, May 5, 2021 at 7:59 PM Pavel Luzanov 
> <p.luzanov@postgrespro.ru> wrote:
>> I found this in the documentation, section '5.11.3. Partitioning 
>> Using Inheritance'[1]: "Some operations require a stronger lock when 
>> using declarative partitioning than when using table inheritance. For 
>> example, removing a partition from a partitioned table requires 
>> taking an ACCESS EXCLUSIVE lock on the parent table, whereas a SHARE 
>> UPDATE EXCLUSIVE lock is enough in the case of regular inheritance." 
>> This point is no longer valid with some restrictions. If the table 
>> has a default partition, then removing a partition still requires 
>> taking an ACCESS EXCLUSIVE lock. May be make sense to add some 
>> details about DETACH CONCURRENTLY to the section '5.11.2.2. Partition 
>> Maintenance' and completely remove this point? 1. 
>> https://www.postgresql.org/docs/devel/ddl-partitioning.html#DDL-PARTITIONING-USING-INHERITANCE
> That makes sense, thanks for noticing. How about the attached? 

I like it.
Especially the link to the ALTER TABLE, this avoids duplication of all 
the nuances of the the DETACH .. CONCURRENTLY.

--
Pavel Luzanov
Postgres Professional: https://postgrespro.com
The Russian Postgres Company

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