blob: daf8eb9a4364ae52f36949e194d2e565299443a8 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
<!--
doc/src/sgml/ref/release_savepoint.sgml
PostgreSQL documentation
-->
<refentry id="sql-release-savepoint">
<indexterm zone="sql-release-savepoint">
<primary>RELEASE SAVEPOINT</primary>
</indexterm>
<indexterm zone="sql-release-savepoint">
<primary>savepoints</primary>
<secondary>releasing</secondary>
</indexterm>
<refmeta>
<refentrytitle>RELEASE SAVEPOINT</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>RELEASE SAVEPOINT</refname>
<refpurpose>destroy a previously defined savepoint</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis>
RELEASE [ SAVEPOINT ] <replaceable>savepoint_name</replaceable>
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>RELEASE SAVEPOINT</command> destroys a savepoint previously defined
in the current transaction.
</para>
<para>
Destroying a savepoint makes it unavailable as a rollback point,
but it has no other user visible behavior. It does not undo the
effects of commands executed after the savepoint was established.
(To do that, see <xref linkend="sql-rollback-to"/>.)
Destroying a savepoint when
it is no longer needed allows the system to reclaim some resources
earlier than transaction end.
</para>
<para>
<command>RELEASE SAVEPOINT</command> also destroys all savepoints that were
established after the named savepoint was established.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><replaceable>savepoint_name</replaceable></term>
<listitem>
<para>
The name of the savepoint to destroy.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
Specifying a savepoint name that was not previously defined is an error.
</para>
<para>
It is not possible to release a savepoint when the transaction is in
an aborted state.
</para>
<para>
If multiple savepoints have the same name, only the most recently defined
unreleased one is released. Repeated commands will release progressively
older savepoints.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To establish and later destroy a savepoint:
<programlisting>
BEGIN;
INSERT INTO table1 VALUES (3);
SAVEPOINT my_savepoint;
INSERT INTO table1 VALUES (4);
RELEASE SAVEPOINT my_savepoint;
COMMIT;
</programlisting>
The above transaction will insert both 3 and 4.
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
This command conforms to the <acronym>SQL</acronym> standard. The standard
specifies that the key word <literal>SAVEPOINT</literal> is
mandatory, but <productname>PostgreSQL</productname> allows it to
be omitted.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-begin"/></member>
<member><xref linkend="sql-commit"/></member>
<member><xref linkend="sql-rollback"/></member>
<member><xref linkend="sql-rollback-to"/></member>
<member><xref linkend="sql-savepoint"/></member>
</simplelist>
</refsect1>
</refentry>
|
