Horton

Re: [HACKERS] Restricting maximum keep segments by repslots

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Cc: michael@paquier.xyz, sawada.mshk@gmail.com, peter.eisentraut@2ndquadrant.com, pgsql-hackers@lists.postgresql.org, thomas.munro@enterprisedb.com, sk@zsrv.org, michael.paquier@gmail.com
Date: 2019-02-16T03:13:23Z
Lists: pgsql-hackers 
Hi,

On 2019-01-30 10:42:04 +0900, Kyotaro HORIGUCHI wrote:
> From 270aff9b08ced425b4c4e23b53193285eb2359a6 Mon Sep 17 00:00:00 2001
> From: Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
> Date: Thu, 21 Dec 2017 21:20:20 +0900
> Subject: [PATCH 1/6] Add WAL relief vent for replication slots
> 
> Adds a capability to limit the number of segments kept by replication
> slots by a GUC variable.

Maybe I'm missing something, but how does this prevent issues with
active slots that are currently accessing the WAL this patch now
suddenly allows to be removed? Especially for logical slots that seems
not unproblematic?

Besides that, this patch needs substantial spelling / language / comment
polishing. Horiguchi-san, it'd probably be good if you could make a
careful pass, and then maybe a native speaker could go over it?

Greetings,

Andres Freund

Commits

  1. Save slot's restart_lsn when invalidated due to size

  2. Fix checkpoint signalling

  3. Check slot->restart_lsn validity in a few more places

  4. Allow users to limit storage reserved by replication slots

  5. Remove header noise from test_decoding test

  6. Rework WAL-reading supporting structs

  7. Flip argument order in XLogSegNoOffsetToRecPtr