postgres.git / summary / log / commit / refs
commit db6e1aeb952e9aed26ba2a56b4145293c72b8068
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Thu May 06 20:42:30 2021 +0000
First released in: 14.0
Improve documentation on DETACH PARTITION lock levels
This was forgotten in 71f4c8c6f74b.
Reported-by: Pavel Luzanov <p.luzanov@postgrespro.ru>
Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/0688e7c3-8bc8-a3e4-9d8e-3bcbbf3e1f4d@postgrespro.ru
doc/src/sgml/ddl.sgml | 24 ++++++++++--------------
doc/src/sgml/ref/alter_table.sgml | 2 +-
2 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index b4648321dc4..63bc946c3b6 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3915,18 +3915,25 @@ DROP TABLE measurement_y2006m02;
<para>
Another option that is often preferable is to remove the partition from
the partitioned table but retain access to it as a table in its own
- right:
+ right. This has two forms:
<programlisting>
ALTER TABLE measurement DETACH PARTITION measurement_y2006m02;
+ALTER TABLE measurement DETACH PARTITION measurement_y2006m02 CONCURRENTLY;
</programlisting>
- This allows further operations to be performed on the data before
+ These allow further operations to be performed on the data before
it is dropped. For example, this is often a useful time to back up
the data using <command>COPY</command>, <application>pg_dump</application>, or
similar tools. It might also be a useful time to aggregate data
into smaller formats, perform other data manipulations, or run
- reports.
+ reports. The first form of the command requires an
+ <literal>ACCESS EXCLUSIVE</literal> lock on the parent table.
+ Adding the <literal>CONCURRENTLY</literal> qualifier as in the second
+ form allows the detach operation to require only
+ <literal>SHARE UPDATE EXCLUSIVE</literal> lock on the parent table, but see
+ <link linkend="sql-altertable-detach-partition"><literal>ALTER TABLE ... DETACH PARTITION</literal></link>
+ for details on the restrictions.
</para>
<para>
@@ -4163,17 +4170,6 @@ ALTER INDEX measurement_city_id_logdate_key
might be poor.)
</para>
</listitem>
-
- <listitem>
- <para>
- 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 <literal>ACCESS EXCLUSIVE</literal> lock on the parent table,
- whereas a <literal>SHARE UPDATE EXCLUSIVE</literal> lock is enough
- in the case of regular inheritance.
- </para>
- </listitem>
</itemizedlist>
</para>
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 9cef1f101eb..087f640dc07 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -967,7 +967,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
</listitem>
</varlistentry>
- <varlistentry>
+ <varlistentry id="sql-altertable-detach-partition">
<term><literal>DETACH PARTITION <replaceable class="parameter">partition_name</replaceable> [ CONCURRENTLY | FINALIZE ]</literal></term>
<listitem>
[parent: c9787385db47]