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
132
133
134
135
136
137
138
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>20.15. Preset Options</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="runtime-config-error-handling.html" title="20.14. Error Handling" /><link rel="next" href="runtime-config-custom.html" title="20.16. Customized Options" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">20.15. Preset Options</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="runtime-config-error-handling.html" title="20.14. Error Handling">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime-config.html" title="Chapter 20. Server Configuration">Up</a></td><th width="60%" align="center">Chapter 20. Server Configuration</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="runtime-config-custom.html" title="20.16. Customized Options">Next</a></td></tr></table><hr /></div><div class="sect1" id="RUNTIME-CONFIG-PRESET"><div class="titlepage"><div><div><h2 class="title" style="clear: both">20.15. Preset Options <a href="#RUNTIME-CONFIG-PRESET" class="id_link">#</a></h2></div></div></div><p>
The following <span class="quote">“<span class="quote">parameters</span>”</span> are read-only.
As such, they have been excluded from the sample
<code class="filename">postgresql.conf</code> file. These options report
various aspects of <span class="productname">PostgreSQL</span> behavior
that might be of interest to certain applications, particularly
administrative front-ends.
Most of them are determined when <span class="productname">PostgreSQL</span>
is compiled or when it is installed.
</p><div class="variablelist"><dl class="variablelist"><dt id="GUC-BLOCK-SIZE"><span class="term"><code class="varname">block_size</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.1.1.3" class="indexterm"></a>
</span> <a href="#GUC-BLOCK-SIZE" class="id_link">#</a></dt><dd><p>
Reports the size of a disk block. It is determined by the value
of <code class="literal">BLCKSZ</code> when building the server. The default
value is 8192 bytes. The meaning of some configuration
variables (such as <a class="xref" href="runtime-config-resource.html#GUC-SHARED-BUFFERS">shared_buffers</a>) is
influenced by <code class="varname">block_size</code>. See <a class="xref" href="runtime-config-resource.html" title="20.4. Resource Consumption">Section 20.4</a> for information.
</p></dd><dt id="GUC-DATA-CHECKSUMS"><span class="term"><code class="varname">data_checksums</code> (<code class="type">boolean</code>)
<a id="id-1.6.7.18.3.2.1.3" class="indexterm"></a>
</span> <a href="#GUC-DATA-CHECKSUMS" class="id_link">#</a></dt><dd><p>
Reports whether data checksums are enabled for this cluster.
See <a class="xref" href="app-initdb.html#APP-INITDB-DATA-CHECKSUMS">data checksums</a> for more information.
</p></dd><dt id="GUC-DATA-DIRECTORY-MODE"><span class="term"><code class="varname">data_directory_mode</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.3.1.3" class="indexterm"></a>
</span> <a href="#GUC-DATA-DIRECTORY-MODE" class="id_link">#</a></dt><dd><p>
On Unix systems this parameter reports the permissions the data
directory (defined by <a class="xref" href="runtime-config-file-locations.html#GUC-DATA-DIRECTORY">data_directory</a>)
had at server startup.
(On Microsoft Windows this parameter will always display
<code class="literal">0700</code>.) See
<a class="xref" href="app-initdb.html#APP-INITDB-ALLOW-GROUP-ACCESS">group access</a> for more information.
</p></dd><dt id="GUC-DEBUG-ASSERTIONS"><span class="term"><code class="varname">debug_assertions</code> (<code class="type">boolean</code>)
<a id="id-1.6.7.18.3.4.1.3" class="indexterm"></a>
</span> <a href="#GUC-DEBUG-ASSERTIONS" class="id_link">#</a></dt><dd><p>
Reports whether <span class="productname">PostgreSQL</span> has been built
with assertions enabled. That is the case if the
macro <code class="symbol">USE_ASSERT_CHECKING</code> is defined
when <span class="productname">PostgreSQL</span> is built (accomplished
e.g., by the <code class="command">configure</code> option
<code class="option">--enable-cassert</code>). By
default <span class="productname">PostgreSQL</span> is built without
assertions.
</p></dd><dt id="GUC-INTEGER-DATETIMES"><span class="term"><code class="varname">integer_datetimes</code> (<code class="type">boolean</code>)
<a id="id-1.6.7.18.3.5.1.3" class="indexterm"></a>
</span> <a href="#GUC-INTEGER-DATETIMES" class="id_link">#</a></dt><dd><p>
Reports whether <span class="productname">PostgreSQL</span> was built with support for
64-bit-integer dates and times. As of <span class="productname">PostgreSQL</span> 10,
this is always <code class="literal">on</code>.
</p></dd><dt id="GUC-IN-HOT-STANDBY"><span class="term"><code class="varname">in_hot_standby</code> (<code class="type">boolean</code>)
<a id="id-1.6.7.18.3.6.1.3" class="indexterm"></a>
</span> <a href="#GUC-IN-HOT-STANDBY" class="id_link">#</a></dt><dd><p>
Reports whether the server is currently in hot standby mode. When
this is <code class="literal">on</code>, all transactions are forced to be
read-only. Within a session, this can change only if the server is
promoted to be primary. See <a class="xref" href="hot-standby.html" title="27.4. Hot Standby">Section 27.4</a> for more
information.
</p></dd><dt id="GUC-MAX-FUNCTION-ARGS"><span class="term"><code class="varname">max_function_args</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.7.1.3" class="indexterm"></a>
</span> <a href="#GUC-MAX-FUNCTION-ARGS" class="id_link">#</a></dt><dd><p>
Reports the maximum number of function arguments. It is determined by
the value of <code class="literal">FUNC_MAX_ARGS</code> when building the server. The
default value is 100 arguments.
</p></dd><dt id="GUC-MAX-IDENTIFIER-LENGTH"><span class="term"><code class="varname">max_identifier_length</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.8.1.3" class="indexterm"></a>
</span> <a href="#GUC-MAX-IDENTIFIER-LENGTH" class="id_link">#</a></dt><dd><p>
Reports the maximum identifier length. It is determined as one
less than the value of <code class="literal">NAMEDATALEN</code> when building
the server. The default value of <code class="literal">NAMEDATALEN</code> is
64; therefore the default
<code class="varname">max_identifier_length</code> is 63 bytes, which
can be less than 63 characters when using multibyte encodings.
</p></dd><dt id="GUC-MAX-INDEX-KEYS"><span class="term"><code class="varname">max_index_keys</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.9.1.3" class="indexterm"></a>
</span> <a href="#GUC-MAX-INDEX-KEYS" class="id_link">#</a></dt><dd><p>
Reports the maximum number of index keys. It is determined by
the value of <code class="literal">INDEX_MAX_KEYS</code> when building the server. The
default value is 32 keys.
</p></dd><dt id="GUC-SEGMENT-SIZE"><span class="term"><code class="varname">segment_size</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.10.1.3" class="indexterm"></a>
</span> <a href="#GUC-SEGMENT-SIZE" class="id_link">#</a></dt><dd><p>
Reports the number of blocks (pages) that can be stored within a file
segment. It is determined by the value of <code class="literal">RELSEG_SIZE</code>
when building the server. The maximum size of a segment file in bytes
is equal to <code class="varname">segment_size</code> multiplied by
<code class="varname">block_size</code>; by default this is 1GB.
</p></dd><dt id="GUC-SERVER-ENCODING"><span class="term"><code class="varname">server_encoding</code> (<code class="type">string</code>)
<a id="id-1.6.7.18.3.11.1.3" class="indexterm"></a>
<a id="id-1.6.7.18.3.11.1.4" class="indexterm"></a>
</span> <a href="#GUC-SERVER-ENCODING" class="id_link">#</a></dt><dd><p>
Reports the database encoding (character set).
It is determined when the database is created. Ordinarily,
clients need only be concerned with the value of <a class="xref" href="runtime-config-client.html#GUC-CLIENT-ENCODING">client_encoding</a>.
</p></dd><dt id="GUC-SERVER-VERSION"><span class="term"><code class="varname">server_version</code> (<code class="type">string</code>)
<a id="id-1.6.7.18.3.12.1.3" class="indexterm"></a>
</span> <a href="#GUC-SERVER-VERSION" class="id_link">#</a></dt><dd><p>
Reports the version number of the server. It is determined by the
value of <code class="literal">PG_VERSION</code> when building the server.
</p></dd><dt id="GUC-SERVER-VERSION-NUM"><span class="term"><code class="varname">server_version_num</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.13.1.3" class="indexterm"></a>
</span> <a href="#GUC-SERVER-VERSION-NUM" class="id_link">#</a></dt><dd><p>
Reports the version number of the server as an integer. It is determined
by the value of <code class="literal">PG_VERSION_NUM</code> when building the server.
</p></dd><dt id="GUC-SHARED-MEMORY-SIZE"><span class="term"><code class="varname">shared_memory_size</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.14.1.3" class="indexterm"></a>
</span> <a href="#GUC-SHARED-MEMORY-SIZE" class="id_link">#</a></dt><dd><p>
Reports the size of the main shared memory area, rounded up to the
nearest megabyte.
</p></dd><dt id="GUC-SHARED-MEMORY-SIZE-IN-HUGE-PAGES"><span class="term"><code class="varname">shared_memory_size_in_huge_pages</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.15.1.3" class="indexterm"></a>
</span> <a href="#GUC-SHARED-MEMORY-SIZE-IN-HUGE-PAGES" class="id_link">#</a></dt><dd><p>
Reports the number of huge pages that are needed for the main shared
memory area based on the specified <a class="xref" href="runtime-config-resource.html#GUC-HUGE-PAGE-SIZE">huge_page_size</a>.
If huge pages are not supported, this will be <code class="literal">-1</code>.
</p><p>
This setting is supported only on <span class="productname">Linux</span>. It
is always set to <code class="literal">-1</code> on other platforms. For more
details about using huge pages on <span class="productname">Linux</span>, see
<a class="xref" href="kernel-resources.html#LINUX-HUGE-PAGES" title="19.4.5. Linux Huge Pages">Section 19.4.5</a>.
</p></dd><dt id="GUC-SSL-LIBRARY"><span class="term"><code class="varname">ssl_library</code> (<code class="type">string</code>)
<a id="id-1.6.7.18.3.16.1.3" class="indexterm"></a>
</span> <a href="#GUC-SSL-LIBRARY" class="id_link">#</a></dt><dd><p>
Reports the name of the SSL library that this
<span class="productname">PostgreSQL</span> server was built with (even if
SSL is not currently configured or in use on this instance), for
example <code class="literal">OpenSSL</code>, or an empty string if none.
</p></dd><dt id="GUC-WAL-BLOCK-SIZE"><span class="term"><code class="varname">wal_block_size</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.17.1.3" class="indexterm"></a>
</span> <a href="#GUC-WAL-BLOCK-SIZE" class="id_link">#</a></dt><dd><p>
Reports the size of a WAL disk block. It is determined by the value
of <code class="literal">XLOG_BLCKSZ</code> when building the server. The default value
is 8192 bytes.
</p></dd><dt id="GUC-WAL-SEGMENT-SIZE"><span class="term"><code class="varname">wal_segment_size</code> (<code class="type">integer</code>)
<a id="id-1.6.7.18.3.18.1.3" class="indexterm"></a>
</span> <a href="#GUC-WAL-SEGMENT-SIZE" class="id_link">#</a></dt><dd><p>
Reports the size of write ahead log segments. The default value is
16MB. See <a class="xref" href="wal-configuration.html" title="30.5. WAL Configuration">Section 30.5</a> for more information.
</p></dd></dl></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="runtime-config-error-handling.html" title="20.14. Error Handling">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime-config.html" title="Chapter 20. Server Configuration">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="runtime-config-custom.html" title="20.16. Customized Options">Next</a></td></tr><tr><td width="40%" align="left" valign="top">20.14. Error Handling </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 20.16. Customized Options</td></tr></table></div></body></html>
|
