pg.ddx.io  pgsql-docs@postgresql.org mailing list archive  

help / color / mirror / Atom feed

From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: pgsql-docs@lists.postgresql.org
Subject: The description for pg_replication_slots.restart_lsn
Date: Wed, 17 Jun 2020 23:47:28 +0900
Message-ID: <6497f1e9-3148-c5da-7e49-b2fddad9a42f@oss.nttdata.com> (raw)

Hi,

The document explains that restart_lsn column in pg_replication_slots view is:

     The address (LSN) of oldest WAL which still might be required by
     the consumer of this slot and thus won't be automatically removed
     during checkpoints.

But the latter part is not true in v13 thanks to max_slot_wal_keep_size.
I think that we need to update it as follows. Thought?

     The address (LSN) of oldest WAL which still might be required by
     the consumer of this slot and thus won't be automatically removed
     during checkpoints unless this LSN gets behind more than
     max_slot_wal_keep_size from the current LSN.

Patch attached.

Regards,
-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION

Attachments:

pg_replication_slots_restart_lsn.patch (text/plain, 793B) download
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 700271fd40..bf326cf533 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -11214,7 +11214,9 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
       <para>
        The address (<literal>LSN</literal>) of oldest WAL which still
        might be required by the consumer of this slot and thus won't be
-       automatically removed during checkpoints.  <literal>NULL</literal>
+       automatically removed during checkpoints unless this LSN
+       gets behind more than <xref linkend="guc-max-slot-wal-keep-size"/>
+       from the current LSN.  <literal>NULL</literal>
        if the <literal>LSN</literal> of this slot has never been reserved.
       </para></entry>
      </row>

view thread (5+ messages)  latest in thread

Message-ID: <6497f1e9-3148-c5da-7e49-b2fddad9a42f@oss.nttdata.com>
Permalink:  ../6497f1e9-3148-c5da-7e49-b2fddad9a42f@oss.nttdata.com/
Also on:    postgresql.org/message-id/6497f1e9-3148-c5da-7e49-b2fddad9a42f@oss.nttdata.com

copy link · copy postgr.es · copy git am

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-docs@postgresql.org
  Cc: masao.fujii@oss.nttdata.com, pgsql-docs@lists.postgresql.org
  Subject: Re: The description for pg_replication_slots.restart_lsn
  In-Reply-To: <6497f1e9-3148-c5da-7e49-b2fddad9a42f@oss.nttdata.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox