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-rw-r--r--doc/src/sgml/mvcc.sgml34
-rw-r--r--doc/src/sgml/ref/lock.sgml79
2 files changed, 81 insertions, 32 deletions
diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 2eaf00803b1..6d7013a46a2 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -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">
@@ -443,6 +443,25 @@ ERROR: Can't serialize access due to concurrent update
<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
</term>
<listitem>
@@ -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>
diff --git a/doc/src/sgml/ref/lock.sgml b/doc/src/sgml/ref/lock.sgml
index bffbb7c23d4..d576890acb9 100644
--- a/doc/src/sgml/ref/lock.sgml
+++ b/doc/src/sgml/ref/lock.sgml
@@ -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>
@@ -103,6 +106,25 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
</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>
<note>
@@ -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>