public inbox for [email protected]
help / color / mirror / Atom feedFrom: Kyotaro Horiguchi <[email protected]>
Subject: [PATCH 5/6] Documentation for slot-limit feature
Date: Thu, 11 Jan 2018 15:00:32 +0900
---
doc/src/sgml/catalogs.sgml | 28 ++++++++++++++++++++++++++++
doc/src/sgml/config.sgml | 23 +++++++++++++++++++++++
doc/src/sgml/high-availability.sgml | 8 +++++---
3 files changed, 56 insertions(+), 3 deletions(-)
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 0fd792ff1a..ad5931800d 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -9865,6 +9865,34 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
</entry>
</row>
+ <row>
+ <entry><structfield>wal_status</structfield></entry>
+ <entry><type>text</type></entry>
+ <entry></entry>
+
+ <entry>Availability of WAL records claimed by this
+ slot. <literal>streaming</literal>, <literal>keeping</literal>,
+ <literal>lost</literal>
+ or <literal>unknown</literal>. <literal>streaming</literal> means that
+ the claimed records are available. <literal>keeping</literal> means that
+ some of them are to be removed by the next checkpoint.
+ <literal>lost</literal> means that some of them are no longer
+ available. The last two states are seen only when
+ <xref linkend="guc-max-slot-wal-keep-size"/> is
+ non-negative. If <structfield>restart_lsn</structfield> is NULL, this
+ field is <literal>unknown</literal>.
+ </entry>
+ </row>
+
+ <row>
+ <entry><structfield>remain</structfield></entry>
+ <entry><type>bigint</type></entry>
+ <entry></entry>
+ <entry>The amount in bytes that WAL location (LSN) can advance until
+ this slot may lose required WAL records.
+ </entry>
+ </row>
+
</tbody>
</tgroup>
</table>
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8bd57f376b..59b5c1b03a 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3573,6 +3573,29 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</listitem>
</varlistentry>
+ <varlistentry id="guc-max-slot-wal-keep-size" xreflabel="max_slot_wal_keep_size">
+ <term><varname>max_slot_wal_keep_size</varname> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>max_slot_wal_keep_size</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Specify the maximum size of WAL files
+ that <link linkend="streaming-replication-slots">replication
+ slots</link> are allowed to retain in the <filename>pg_wal</filename>
+ directory at checkpoint time.
+ If <varname>max_slot_wal_keep_size</varname> is -1 (the default),
+ replication slots retain unlimited size of WAL files. If restart_lsn
+ of a replication slot gets behind more than that bytes from the
+ current LSN, the standby using the slot may no longer be able to
+ reconnect due to removal of required WAL records. You can see the WAL
+ availability of replication slots
+ in <link linkend="view-pg-replication-slots">pg_replication_slots</link>.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-wal-sender-timeout" xreflabel="wal_sender_timeout">
<term><varname>wal_sender_timeout</varname> (<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 2b4dcd03c8..d52ffd97a3 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -925,9 +925,11 @@ primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass'
<xref linkend="guc-archive-command"/>.
However, these methods often result in retaining more WAL segments than
required, whereas replication slots retain only the number of segments
- known to be needed. An advantage of these methods is that they bound
- the space requirement for <literal>pg_wal</literal>; there is currently no way
- to do this using replication slots.
+ known to be needed. On the other hand, replication slots can retain so
+ many WAL segments that they fill up the space allocated
+ for <literal>pg_wal</literal>;
+ <xref linkend="guc-max-slot-wal-keep-size"/> limits the size of WAL files
+ retained by replication slots.
</para>
<para>
Similarly, <xref linkend="guc-hot-standby-feedback"/>
--
2.16.3
----Next_Part(Fri_Feb_22_14_12_28_2019_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0006-Check-removal-of-in-reading-segment-file.patch"
view thread (6+ messages) latest in thread
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: [email protected]
Cc: [email protected]
Subject: Re: [PATCH 5/6] Documentation for slot-limit feature
In-Reply-To: <no-message-id-1883526@localhost>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox