Horton

Re: BUG #17103: WAL segments are not removed after exceeding max_slot_wal_keep_size

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

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: jeff.janes@gmail.com, mk@071.ovh, pgsql-bugs@lists.postgresql.org
Date: 2021-07-15T19:09:55Z
Lists: pgsql-bugs

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On 2021-Jul-15, Kyotaro Horiguchi wrote:

> This is it. It is for the master branch but also applicable to 14 as
> is. Not needed for earlier version.
> I believe the test works for Windows but haven't checked.

I looked at it.  I think it is better to make the calls to 
ReplicationSlotsComputeRequiredLSN() in slot.c (which is where most other
calls to that function are).  Also we should recompute the minimum
required Xmin at that point.

Another change I did was move the "*invalidated=true" assignment to the
block where we actually invalidate the slot; in your patch you were
doing it possibly too early if the slot was in use by some other
process.  (For end effect it probably doesn't matter much, but it's
better to have it right.)

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/

Commits

  1. Close yet another race condition in replication slot test code

  2. Make new replication slot test code even less racy

  3. Make new replication slot test code less racy

  4. Advance old-segment horizon properly after slot invalidation