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Add SHARE UPDATE EXCLUSIVE lock mode, coming soon to a VACUUM near you.

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Name chosen per pghackers discussion around 6/22/01.
This commit is contained in:
Tom Lane
2001-07-09 22:18:34 +00:00
parent 8902f49abb
commit 4fe42dfbc3
8 changed files with 143 additions and 80 deletions
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34
doc/src/sgml/mvcc.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.15 2001/05/17 21:50:16 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.16 2001/07/09 22:18:33 tgl Exp $
-->
<chapter id="mvcc">
@ -441,6 +441,25 @@ ERROR: Can't serialize access due to concurrent update
</listitem>
</varlistentry>
<varlistentry>
<term>
ShareUpdateExclusiveLock
</term>
<listitem>
<para>
Acquired by <command>VACUUM</command> (without <option>FULL</option>)
and <command>LOCK TABLE</command> table
for <option>IN SHARE UPDATE EXCLUSIVE MODE</option>
statements.
</para>
<para>
Conflicts with ShareUpdateExclusiveLock, ShareLock,
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock modes.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
ShareLock
@ -454,7 +473,8 @@ ERROR: Can't serialize access due to concurrent update
</para>
<para>
Conflicts with RowExclusiveLock, ShareRowExclusiveLock,
Conflicts with RowExclusiveLock, ShareUpdateExclusiveLock,
ShareRowExclusiveLock,
ExclusiveLock and AccessExclusiveLock modes.
</para>
</listitem>
@ -471,7 +491,8 @@ ERROR: Can't serialize access due to concurrent update
</para>
<para>
Conflicts with RowExclusiveLock, ShareLock, ShareRowExclusiveLock,
Conflicts with RowExclusiveLock, ShareUpdateExclusiveLock,
ShareLock, ShareRowExclusiveLock,
ExclusiveLock and AccessExclusiveLock modes.
</para>
</listitem>
@ -488,7 +509,8 @@ ERROR: Can't serialize access due to concurrent update
</para>
<para>
Conflicts with RowShareLock, RowExclusiveLock, ShareLock,
Conflicts with RowShareLock, RowExclusiveLock,
ShareUpdateExclusiveLock, ShareLock,
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock
modes.
</para>
@ -503,13 +525,13 @@ ERROR: Can't serialize access due to concurrent update
<para>
Acquired by <command>ALTER TABLE</command>,
<command>DROP TABLE</command>,
<command>VACUUM</command> and <command>LOCK TABLE</command>
<command>VACUUM FULL</command> and <command>LOCK TABLE</command>
statements.
</para>
<para>
Conflicts with all modes (AccessShareLock, RowShareLock,
RowExclusiveLock, ShareLock,
RowExclusiveLock, ShareUpdateExclusiveLock, ShareLock,
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock).
</para>
</listitem>

79
doc/src/sgml/ref/lock.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/lock.sgml,v 1.23 2000/12/25 23:15:26 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/lock.sgml,v 1.24 2001/07/09 22:18:33 tgl Exp $
Postgres documentation
-->
@ -20,12 +20,16 @@ Postgres documentation
</refnamediv>
<refsynopsisdiv>
<refsynopsisdivinfo>
<date>1999-07-20</date>
<date>2001-07-09</date>
</refsynopsisdivinfo>
<synopsis>
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN [ ROW | ACCESS ] { SHARE | EXCLUSIVE } MODE
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EXCLUSIVE MODE
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN <replaceable class="PARAMETER">lockmode</replaceable> MODE
where <replaceable class="PARAMETER">lockmode</replaceable> is one of:
ACCESS SHARE | ROW SHARE | ROW EXCLUSIVE | SHARE UPDATE EXCLUSIVE |
SHARE | SHARE ROW EXCLUSIVE | EXCLUSIVE | ACCESS EXCLUSIVE
</synopsis>
<refsect2 id="R2-SQL-LOCK-1">
@ -33,7 +37,6 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
<date>1999-06-09</date>
</refsect2info>
<title>
Inputs
</title>
@ -62,7 +65,7 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
This is the least restrictive lock mode. It conflicts only with
ACCESS EXCLUSIVE mode. It is used to protect a table from being
modified by concurrent <command>ALTER TABLE</command>,
<command>DROP TABLE</command> and <command>VACUUM</command>
<command>DROP TABLE</command> and <command>VACUUM FULL</command>
commands.
</para>
</listitem>
@ -102,6 +105,25 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
</listitem>
</varlistentry>
<varlistentry>
<term>SHARE UPDATE EXCLUSIVE MODE</term>
<listitem>
<note>
<para>
Automatically acquired by <command>VACUUM</command> (without
<option>FULL</option>).
</para>
</note>
<para>
Conflicts with SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
EXCLUSIVE and
ACCESS EXCLUSIVE modes. This mode protects a table against
concurrent schema changes and VACUUMs.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SHARE MODE</term>
<listitem>
@ -113,9 +135,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
</note>
<para>
Conflicts with ROW EXCLUSIVE, SHARE ROW EXCLUSIVE, EXCLUSIVE and
Conflicts with ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE,
SHARE ROW EXCLUSIVE, EXCLUSIVE and
ACCESS EXCLUSIVE modes. This mode protects a table against
concurrent updates.
concurrent data updates.
</para>
</listitem>
</varlistentry>
@ -125,14 +148,14 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
<listitem>
<note>
<para>
This is like EXCLUSIVE MODE, but allows SHARE ROW locks
This is like EXCLUSIVE MODE, but allows ROW SHARE locks
by others.
</para>
</note>
<para>
Conflicts with ROW EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
EXCLUSIVE and ACCESS EXCLUSIVE modes.
Conflicts with ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE, SHARE,
SHARE ROW EXCLUSIVE, EXCLUSIVE and ACCESS EXCLUSIVE modes.
</para>
</listitem>
</varlistentry>
@ -149,7 +172,8 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
</note>
<para>
Conflicts with ROW SHARE, ROW EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
Conflicts with ROW SHARE, ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE,
SHARE, SHARE ROW EXCLUSIVE,
EXCLUSIVE and ACCESS EXCLUSIVE modes.
</para>
</listitem>
@ -161,9 +185,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
<note>
<para>
Automatically acquired by <command>ALTER TABLE</command>,
<command>DROP TABLE</command>, <command>VACUUM</command> statements.
This is the most restrictive lock mode which conflicts with all other
lock modes and protects a locked table from any concurrent operations.
<command>DROP TABLE</command>, <command>VACUUM FULL</command>
statements.
This is the most restrictive lock mode which
protects a locked table from any concurrent operations.
</para>
</note>
@ -174,6 +199,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
lock mode option).
</para>
</note>
<para>
Conflicts with all lock modes.
</para>
</listitem>
</varlistentry>
</variablelist>
@ -241,7 +270,11 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
<term>EXCLUSIVE</term>
<listitem>
<para>
Exclusive lock that prevents other locks from being granted.
An exclusive lock prevents other locks of the same type from being
granted. (Note: ROW EXCLUSIVE mode does not follow this naming
convention perfectly, since it is shared at the level of the table;
it is exclusive only with respect to specific rows that are being
updated.)
</para>
</listitem>
</varlistentry>
@ -250,7 +283,8 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
<term>SHARE</term>
<listitem>
<para>
Allows others to share lock. Prevents EXCLUSIVE locks.
A shared lock allows others to also hold the same type of lock,
but prevents the corresponding EXCLUSIVE lock from being granted.
</para>
</listitem>
</varlistentry>
@ -273,13 +307,6 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
</listitem>
</varlistentry>
</variablelist>
<note>
<para>
If EXCLUSIVE or SHARE are not specified, EXCLUSIVE is assumed.
Locks exist for the duration of the transaction.
</para>
</note>
</para>
<para>
@ -370,8 +397,8 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
</para>
<para>
Except for ACCESS SHARE/EXCLUSIVE lock modes, all other
<productname>Postgres</productname> lock modes and the
Except for ACCESS SHARE, ACCESS EXCLUSIVE, and SHARE UPDATE EXCLUSIVE lock
modes, the <productname>Postgres</productname> lock modes and the
<command>LOCK TABLE</command> syntax are compatible with those
present in <productname>Oracle</productname>.
</para>