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<indexterm zone="functions-admin">

<primary>pg_reload_conf</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>pg_rotate_logfile</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>signal</primary>

<entry><type>int</type></entry>

<entry>Cause server processes to reload their configuration files</entry>

</row>

<row>

<entry>

<literal><function>pg_rotate_logfile</function>()</literal>

</entry>

<entry><type>int</type></entry>

<entry>Rotate server's logfile</entry>

</row>

</tbody>

</tgroup>

</table>

<para>

These functions return 1 if successful, 0 if not successful.

The process ID (<literal>pid</literal>) of an active backend can be found

from the <structfield>procpid</structfield> column in the

<structname>pg_stat_activity</structname> view, or by listing the <command>postgres</command>

processes on the server with <application>ps</>.

Each of these functions returns 1 if successful, 0 if not successful.

</para>

<para>

<function>pg_cancel_backend</> sends a Query Cancel (SIGINT) signal

to a backend process identified by process ID (<literal>pid</literal>).

The process ID of an active backend can be found from the

<structfield>procpid</structfield> column in the

<structname>pg_stat_activity</structname> view, or by listing the

<command>postgres</command> processes on the server with

<application>ps</>.

</para>

<para>

<function>pg_reload_conf</> sends a SIGHUP signal to the

postmaster, causing reload of the configuration files

in all server processes.

</para>

<para>

<function>pg_rotate_logfile</> signals the logfile manager to switch

to a new output file immediately. This works only when

<varname>redirect_stderr</> is used for logging, since otherwise there

is no logfile manager subprocess.

</para>

<indexterm zone="functions-admin">

<primary>pg_start_backup</primary>

</indexterm>

</thead>

<tbody>

<row>

<entry>

<literal><function>pg_file_length</function>(<parameter>filename</> <type>text</>)</literal>

<indexterm zone="functions-admin">

<primary>pg_file_length</primary>

</indexterm>

</entry>

<entry><type>int8</type></entry>

<entry>Return the file length</entry>

</row>

<row>

<entry>

<literal><function>pg_ls_dir</function>(<parameter>dirname</> <type>text</>)</literal>

<indexterm zone="functions-admin">

<primary>pg_ls_dir</primary>

</indexterm>

</entry>

<entry><type>setof text</type></entry>

<entry>List the contents of a directory</entry>

<literal><function>pg_stat_file</function>(<parameter>filename</> <type>text</>)</literal>

</entry>

<entry><type>record</type></entry>

<entry>Return information aboutthe file</entry>

<entry>Return information abouta file</entry>

</row>

</tbody>

</tgroup>

</table>

<indexterm zone="functions-admin">

<primary>pg_ls_dir</primary>

</indexterm>

<para>

<function>pg_ls_dir()</> returns all the names in the specified

directory, except the special entries <quote><literal>.</></> and

<quote><literal>..</></>.

</para>

<indexterm zone="functions-admin">

<primary>pg_read_file</primary>

</indexterm>

<para>

<function>pg_read_file()</> returns part of atextfile, starting

at the given offset, returning at most length bytes (less if the

end of file is reached first). If offset is negative,

it is relative to the end of the file.

<function>pg_read_file()</> returns part of atext file, starting

at the given<parameter>offset</>, returning at most<parameter>length</>

bytes (less if theend of file is reached first). If<parameter>offset</>

is negative,it is relative to the end of the file.

</para>

<indexterm zone="functions-admin">

<primary>pg_stat_file</primary>

</indexterm>

<para>

<function>pg_stat_file()</> returns a record containing the

<function>pg_stat_file()</> returns a record containing the file

length, last accessed timestamp, last modified timestamp,

creation timestamp, and aflag indicating if it is a directory.

Use it like this:

creation timestamp, and aboolean indicating if it is a directory.

Typical usages include:

<programlisting>

SELECT *

FROM pg_stat_file('filename')

AS s(length int8, atime timestamptz, mtime timestamptz,

ctime timestamptz, isdir bool);

SELECT * FROM pg_stat_file('filename');

SELECT (pg_stat_file('filename')).mtime;

</programlisting>

</para>

<para>

The function shown in <xref

linkend="functions-admin-logfile"> forces the server

logfile to be rotated. This works only when <varname>redirect_stderr</>

is used for logging. Use of this function is restricted

to superusers.

</para>

<table id="functions-admin-logfile">

<title>Server Logfile Functions</title>

<tgroup cols="3">

<thead>

<row><entry>Name</entry> <entry>Return Type</entry> <entry>Description</entry>

</row>

</thead>

<tbody>

<row>

<entry>

<literal><function>pg_rotate_logfile</function>()</literal>

<indexterm zone="functions-admin">

<primary>pg_rotate_logfile</primary>

</indexterm>

</entry>

<entry><type>int</type></entry>

<entry>Rotate server's logfile</entry>

</row>

</tbody>

</tgroup>

</table>

</sect1>

</chapter>

pg_stat_get_db_blocks_hit(D.oid)AS blks_read,

pg_stat_get_db_blocks_hit(D.oid)AS blks_hit

FROM pg_database D;

UPDATE pg_procSET

proallargtypes= ARRAY['text'::regtype,

'int8',

'timestamptz',

'timestamptz',

'timestamptz',

'bool'],

proargmodes= ARRAY['i'::"char",'o','o','o','o','o'],

proargnames= ARRAY['filename'::text,

'length','atime','mtime','ctime','isdir']

WHEREoid='pg_stat_file(text)'::regprocedure;

(errcode_for_file_access(),

errmsg("could not stat file \"%s\": %m",filename)));

tupdesc=CreateTemplateTupleDesc(5, false);

TupleDescInitEntry(tupdesc, (AttrNumber)1,

"length",INT8OID,-1,0);

DATA(insertOID=2621 (pg_reload_confPGNSPPGUID12fftfv023""_null__null__null_pg_reload_conf-_null_ ));

DESCR("Reload configuration files");

DATA(insertOID=2622 (pg_rotate_logfilePGNSPPGUID12fftfv023""_null__null__null_pg_rotate_logfile-_null_ ));

DESCR("Rotate log file");

DATA(insertOID=2623 (pg_stat_filePGNSPPGUID12fftfv12249"25"_null__null__null_pg_stat_file-_null_ ));

DESCR("Return file information");

DATA(insertOID=2624 (pg_file_lengthPGNSPPGUID14fftfv120"25"_null__null__null_"SELECT len FROM pg_stat_file($1) AS s(len int8, a timestamptz, m timestamptz, c timestamptz, i bool)"-_null_ ));

DESCR("Return file length");

DATA(insertOID=2625 (pg_read_filePGNSPPGUID12fftfv325"25 20 20"_null__null__null_pg_read_file-_null_ ));

DATA(insertOID=2624 (pg_read_filePGNSPPGUID12fftfv325"25 20 20"_null__null__null_pg_read_file-_null_ ));

DESCR("Read text from a file");

DATA(insertOID=2626 (pg_ls_dirPGNSPPGUID12ffttv125"25"_null__null__null_pg_ls_dir-_null_ ));

DATA(insertOID=2625 (pg_ls_dirPGNSPPGUID12ffttv125"25"_null__null__null_pg_ls_dir-_null_ ));

DESCR("List all files in a directory");