<!--

$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.276 2005/08/02 16:11:56 tgl Exp $

$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.277 2005/08/12 03:23:40 momjian Exp $

PostgreSQL documentation

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<indexterm zone="functions-admin">

<primary>pg_cancel_backend</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>pg_reload_conf</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>signal</primary>

<secondary sortas="backend">backend processes</secondary>

</indexterm>

<para>

Thefunction shown in <xref

Thefunctions shown in <xref

linkend="functions-admin-signal-table"> sends control signals to

other server processes. Use of this function is restricted

to superusers.

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

<entry>Cancel a backend's current query</entry>

</row>

<row>

<entry>

<literal><function>pg_reload_conf</function>()</literal>

</entry>

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

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

</row>

</tbody>

</tgroup>

</table>

<para>

This function returns 1 if successful, 0 if not successful.

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</>.

</para>

<para>

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

postmaster, causing the reload of the configuration files

in all backend processes.

</para>

<indexterm zone="functions-admin">

<primary>pg_start_backup</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>pg_stop_backup</primary>

</indexterm>

<indexterm zone="functions-admin">

<primary>backup</primary>

</indexterm>

appropriate.

</para>

<para>

The functions shown in <xref

linkend="functions-admin-genfile"> provide native file access to

files on the machine hosting the server. Only files relative to

the cluster directory are allowed, and the logfile directory,

because the logfile directory might be stored outside the

cluster directory. Use of these functions is restricted to

superusers.

</para>

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

<title>Generic File Access 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_file_length</function>(<parameter>filename_text</parameter>)</literal>

<indexterm zone="functions-admin">

<primary>pg_file_length</primary>

</indexterm>

</entry>

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

<entry>Returns the file length</entry>

</row>

<row>

<entry>

<literal><function>pg_ls_dir</function>(<parameter>dirname_text</parameter>,<parameter>fullpath_bool</parameter>)</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>

</row>

<row>

<entry>

<literal><function>pg_read_file</function>(<parameter>filename_text</parameter>,

<parameter>offset_int8</parameter>,<parameter>length_int8</parameter>)</literal>

</entry>

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

<entry>Returns the contents of a text file</entry>

</row>

<row>

<entry>

<literal><function>pg_stat_file</function>(<parameter>filename_text</parameter>)</literal>

</entry>

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

<entry>Returns information about the file</entry>

</row>

</tbody>

</tgroup>

</table>

<indexterm zone="functions-admin">

<primary>pg_read_file</primary>

</indexterm>

<para>

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

at the given offset, returning length bytes. If offset is negative,

it is treated 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

length, last accessed timestamp, last modified timestamp,

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

</para>

<para>

The function shown in <xref

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

logfile to be rotated if <varname>redirect_stderr</>

is used for logging. Use of this functions is restricted

to superusers.

</para>

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

<title>Backend 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 logfile</entry>

</row>

</tbody>

</tgroup>

</table>

</sect1>

</chapter>

}

}

if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE)&&SysLoggerPID!=0)

kill(SysLoggerPID,SIGUSR1);

PG_SETMASK(&UnBlockSig);

errno=save_errno;

staticvolatilesig_atomic_tgot_SIGHUP= false;

staticvolatilesig_atomic_trotation_requested= false;

staticchar*logfile_getname(pg_time_ttimestamp);

staticvoidset_next_rotation_time(void);

staticvoidsigHupHandler(SIGNAL_ARGS);

staticvoidsigUsr1Handler(SIGNAL_ARGS);

pqsignal(SIGQUIT,SIG_IGN);

pqsignal(SIGALRM,SIG_IGN);

pqsignal(SIGPIPE,SIG_IGN);

pqsignal(SIGUSR1,SIG_IGN);

pqsignal(SIGUSR1,sigUsr1Handler);/* request log rotation */

pqsignal(SIGUSR2,SIG_IGN);

for (;;)

{

boolrotation_requested= false;

booltime_based_rotation= false;

char*filename;

FILE*fh;

rotation_requested= false;

{

got_SIGHUP= true;

}

sigUsr1Handler(SIGNAL_ARGS)

{

rotation_requested= true;

}

subdir = src/backend/utils/adt

tid.o timestamp.o varbit.o varchar.o varlena.o version.o xid.o\

network.o mac.o inet_net_ntop.o inet_net_pton.o\

ri_triggers.o pg_lzcompress.o pg_locale.o formatting.o\

ascii.o quote.o pgstatfuncs.o encode.o dbsize.o

ascii.o quote.o pgstatfuncs.o encode.o dbsize.o genfile.o

like.o: like.c like_match.c