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$Header: /cvsroot/pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.7 1999/10/12 13:59:45 thomas Exp $

$Header: /cvsroot/pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.8 2000/03/26 07:04:54 tgl Exp $

Postgres documentation

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<date>1999-07-20</date>

</refsynopsisdivinfo>

<synopsis>

postmaster [ -B <replaceable class="parameter">nBuffers</replaceable> ] [ -D <replaceable class="parameter">DataDir</replaceable> ] [ -i ] [ -l ]

postmaster [ -B <replaceable class="parameter">nBuffers</replaceable> ] [ -D <replaceable class="parameter">DataDir</replaceable> ] [ -N <replaceable class="parameter">nBackends</replaceable> ] [ -S ]

[ -d [ <replaceable class="parameter">DebugLevel</replaceable> ] [ -i ] [ -l ] [ -o <replaceable class="parameter">BackendOptions</replaceable> ] [ -p <replaceable class="parameter">port</replaceable> ]

postmaster [ -n | -s ] ...

postmaster [ -B <replaceable class="parameter">nBuffers</replaceable> ] [ -D <replaceable class="parameter">DataDir</replaceable> ] [ -N <replaceable class="parameter">maxBackends</replaceable> ] [ -S ]

[ -d <replaceable class="parameter">DebugLevel</replaceable> ] [ -i ] [ -l ]

[ -o <replaceable class="parameter">BackendOptions</replaceable> ] [ -p <replaceable class="parameter">port</replaceable> ] [ -n | -s ]

</synopsis>

<refsect2 id="R2-APP-POSTMASTER-1">

<term>-B <replaceable class="parameter">nBuffers</replaceable></term>

<listitem>

<para>

Thenumber of shared-memory buffers for the

Sets thenumber of shared-memory disk buffers for the

<application>postmaster</application>

to allocateand manage for the backend server processes that it

to allocatefor use by the backend server processes that it

starts. This value defaults to 64 buffers, where each buffer is 8k bytes

(or whatever BLCKSZ is set to in config.h).

(or whatever BLCKSZ is set to insrc/include/config.h).

</para>

</listitem>

</varlistentry>

</varlistentry>

<varlistentry>

<term>-N <replaceable class="parameter">nBackends</replaceable></term>

<term>-N <replaceable class="parameter">maxBackends</replaceable></term>

<listitem>

<para>

The maximum number of backend server processes that this postmaster

is allowed to start. In the default configuration, this value

is usually set

to 32, and can be set as high as 1024 if your system will support that

many processes. Both the default and upper limit values can be altered

when building <productname>Postgres</productname> (see src/include/config.h).

Sets the maximum number of backend server processes that this postmaster

is allowed to start. By default, this value is 32, but it can be set

as high as 1024 if your system will support that many processes.

(Note that -B is required to be at least twice -N, so you'll need to

increase -B if you increase -N.)

Both the default and upper limit values for -N can be altered

when building <productname>Postgres</productname>

(see src/include/config.h).

</para>

</listitem>

</varlistentry>

<para>

Specifies that the <application>postmaster</application>

process should start up in silent mode. That is, it will disassociate

from the user's (controlling) tty and start its own process group.

This should not be used in combination with debugging options because

any messages printed to standard output and standard error are

discarded.

from the user's (controlling) tty, start its own process group, and

redirect its standard output and standard error to

<filename>/dev/null</filename>.

</para>

<para>

<emphasis>Note</emphasis> that using this switch makes it very

difficult to troubleshoot problems, since all tracing and logging

output that would normally be generated by this postmaster and its

child backends will be discarded.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term>-d[<replaceable class="parameter">DebugLevel</replaceable> ]</term>

<term>-d <replaceable class="parameter">DebugLevel</replaceable></term>

<listitem>

<para>

This argument <replaceable class="parameter">DebugLevel</replaceable>

determines the amount of debugging output the backend servers will

Determines the amount of debugging output the backend servers will

produce.

If <replaceable class="parameter">DebugLevel</replaceable>

is one, the postmaster will trace all connection traffic,

and nothing else.

For levels two and higher,

debugging is turned on in the backend process and the postmaster

displays more information,

is one, the postmaster will trace all connection traffic.

Levels two and higher turn on increasing amounts of debug output

from the backend processes, and the postmaster

displays more information

including the backend environment and process traffic.

Note thatif no file is specified for backend servers to

send their debugging output then this output will appear on the

controlling tty oftheir parent <application>postmaster</application>.

Note thatunless the postmaster's standard output and standard error

are redirected into a log file, all this output will appear on the

controlling tty ofthe <application>postmaster</application>.

</para>

</listitem>

</varlistentry>

<term>-i</term>

<listitem>

<para>

This enablesTCP/IPorInternet domain socket communication.

Without this option, only local Unix domain socketcommunication is

possible.

Allows clients to connect viaTCP/IP(Internet domain) connections.

Without this option, only local Unix domain socketconnections are

accepted.

</para>

</listitem>

</varlistentry>

<term>-l</term>

<listitem>

<para>

This enables SSL socket communication. The <option>-i</option> option

Enables secure connections using SSL. The <option>-i</option> option

is also required.

Youhave to have compiled with SSL enabled to use this option.

Youmust have compiled with SSL enabled to use this option.

</para>

</listitem>

</varlistentry>

<para>

The

<literal>postgres</literal>

options specified in

option(s) specified in

<replaceable class="parameter">BackendOptions</replaceable>

are passed to all backend server processes started by this

<application>postmaster</application>.

</para>

<para>

A few command line options are available for debuggingin the case

whena backenddies abnormally.

Two additional command line options are available for debuggingproblems

that causea backendto die abnormally.

These options control the behavior of the

<application>postmaster</application> in this situation, and

<emphasis>neither option is intended for use in

<listitem>

<para>

<application>postmaster</application>

will not reinitialize shared data structures. A knowledgable system

programmer can then use the

<application>shmemdoc</application>

program to examine shared memory and semaphore state.

will not reinitialize shared data structures. A knowledgeable system

programmer can then use a debugger

to examine shared memory and semaphore state.

</para>

</listitem>

</varlistentry>

<para>

If you see this message, you should run the

<application>ipcclean</application>

command. After doingthis, try starting

command. After doingso, try starting

<application>postmaster</application>

again. If this still doesn't work, you probably need to configure

your kernel for shared memory and semaphores as described in the

You may be able to postpone

reconfiguring your kernel by decreasing -B to reduce

<productname>Postgres</productname>' shared memory

consumption, or by reducing -N to reduce Postgres' semaphore

consumption,and/or by reducing -N to reduce Postgres' semaphore

consumption.

</para>

</tip>

</computeroutput></term>

<listitem>

<para>

If you see this message, you shouldbe certain that there is no other

<application>postmaster</application>

process already running. The easiest way to determine this is by

using the command

If you see this message, you shouldmake certain that there is no

other<application>postmaster</application>

process already running on the same port number. The easiest way to

determine this is byusing the command

<programlisting>

% ps -ax | grep postmaster

</programlisting>

will prevent <application>postmaster</application>

from freeing the system resources (e.g., shared memory and semaphores)

that it holds before dying.This prevents you from having to deal with

the problem with shared memorydescribed earlier.

that it holds before dying.Use <literal>SIGTERM</literal> instead

to avoid having to clean up manually (asdescribed earlier).

</para>

<para>

</para>

<para>

To start <application>postmaster</application> with a specific port

and executable name:

To start <application>postmaster</application> with a specific port:

<programlisting>

% nohup postmaster -p 1234 &