postgres-ref.sgml

postgresql8.3.4源码,开源数据库

       <para>
        Allows the structure of system tables to be modified.  This is
        used by <command>initdb</command>.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-P</option></term>
      <listitem>
       <para>
        Ignore system indexes when reading system tables (but still update
        the indexes when modifying the tables).  This is useful when
        recovering from damaged system indexes.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-t</option> <literal>pa[rser] | pl[anner] | e[xecutor]</literal></term>
      <listitem>
       <para>
        Print timing statistics for each query relating to each of the
        major system modules.  This option cannot be used together
        with the <option>-s</option> option.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-T</option></term>
      <listitem>
       <para>
        This option is for debugging problems that cause a server
        process to die abnormally.  The ordinary strategy in this
        situation is to notify all other server processes that they
        must terminate and then reinitialize the shared memory and
        semaphores.  This is because an errant server process could
        have corrupted some shared state before terminating.  This
        option specifies that <command>postgres</command> will
        stop all other server processes by sending the signal
        <literal>SIGSTOP</literal>, but will not cause them to
        terminate.  This permits system programmers to collect core
        dumps from all server processes by hand.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-v</option> <replaceable class="parameter">protocol</replaceable></term>
      <listitem>
       <para>
        Specifies the version number of the frontend/backend protocol
        to be used for a particular session.  This option is for
        internal use only.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-W</option> <replaceable class="parameter">seconds</replaceable></term>
      <listitem>
       <para>
        A delay of this many seconds occurs when a new server process
        is started, after it conducts the authentication procedure.
        This is intended to give an opportunity to attach to the
        server process with a debugger.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </refsect2>

   <refsect2>
    <title>Options for single-user mode</title>

    <para>
     The following options only apply to the single-user mode.
    </para>

    <variablelist>
     <varlistentry>
      <term><option>--single</option></term>
      <listitem>
       <para>
        Selects the single-user mode.  This must be the first argument
        on the command line.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable class="parameter">database</replaceable></term>
      <listitem>
       <para>
        Specifies the name of the database to be accessed.  This must be
        the last argument on the command line.  If it is
        omitted it defaults to the user name.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-E</option></term>
      <listitem>
       <para>
        Echo all commands.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-j</option></term>
      <listitem>
       <para>
        Disables use of newline as a statement delimiter.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-r</option> <replaceable class="parameter">filename</replaceable></term>
      <listitem>
       <para>
        Send all server log output to <replaceable
        class="parameter">filename</replaceable>.  In normal multiuser
        mode, this option is ignored, and <systemitem>stderr</> is
        used by all processes.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
   </refsect2>
 </refsect1>

 <refsect1>
  <title>Environment</title>

  <variablelist>
   <varlistentry>
    <term><envar>PGCLIENTENCODING</envar></term>

    <listitem>
     <para>
      Default character encoding used by clients.  (The clients can
      override this individually.)  This value can also be set in the
      configuration file.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PGDATA</envar></term>

    <listitem>
     <para>
      Default data directory location
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PGDATESTYLE</envar></term>

    <listitem>
     <para>
      Default value of the <xref linkend="guc-datestyle"> run-time
      parameter.  (The use of this environment variable is deprecated.)
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PGPORT</envar></term>

    <listitem>
     <para>
      Default port (preferably set in the configuration file)
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>TZ</envar></term>

    <listitem>
     <para>
      Server time zone
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </refsect1>

 <refsect1>
   <title>Diagnostics</title>

   <para>
    A failure message mentioning <literal>semget</> or
    <literal>shmget</> probably indicates you need to configure your
    kernel to provide adequate shared memory and semaphores.  For more
    discussion see <xref linkend="kernel-resources">.  You might be able
    to postpone reconfiguring your kernel by decreasing <xref
    linkend="guc-shared-buffers"> to reduce the shared memory
    consumption of <productname>PostgreSQL</>, and/or by reducing
    <xref linkend="guc-max-connections"> to reduce the semaphore
    consumption.
   </para>

   <para>
    A failure message suggesting that another server is already running
    should be checked carefully, for example by using the command
<screen>
<prompt>$</prompt> <userinput>ps ax | grep postgres</userinput>
</screen>
        or
<screen>
<prompt>$</prompt> <userinput>ps -ef | grep postgres</userinput>
</screen>
    depending on your system.  If you are certain that no conflicting
    server is running, you can remove the lock file mentioned in the
    message and try again.
   </para>

   <para>
    A failure message indicating inability to bind to a port might
    indicate that that port is already in use by some
    non-<productname>PostgreSQL</productname> process.  You might also
    get this error if you terminate <command>postgres</command>
    and immediately restart it using the same port; in this case, you
    must simply wait a few seconds until the operating system closes
    the port before trying again.  Finally, you might get this error if
    you specify a port number that your operating system considers to
    be reserved.  For example, many versions of Unix consider port
    numbers under 1024 to be <quote>trusted</quote> and only permit
    the Unix superuser to access them.
   </para>

 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   The utility command <xref linkend="app-pg-ctl"> can be used to
   start and shut down the <command>postgres</command> server
   safely and comfortably.
  </para>
  
  <para>
   If at all possible, <emphasis>do not</emphasis> use
   <literal>SIGKILL</literal> to kill the main
   <command>postgres</command> server.  Doing so will prevent
   <command>postgres</command> from freeing the system
   resources (e.g., shared memory and semaphores) that it holds before
   terminating.  This might cause problems for starting a fresh
   <command>postgres</command> run.
  </para>

  <para>
   To terminate the <command>postgres</command> server normally, the
   signals <literal>SIGTERM</literal>, <literal>SIGINT</literal>, or
   <literal>SIGQUIT</literal> can be used.  The first will wait for
   all clients to terminate before quitting, the second will
   forcefully disconnect all clients, and the third will quit
   immediately without proper shutdown, resulting in a recovery run
   during restart.
  </para>

  <para>
   The <literal>SIGHUP</literal> signal will reload
   the server configuration files.  It is also possible to send
   <literal>SIGHUP</literal> to an individual server process, but that
   is usually not sensible.
  </para>

  <para>
   To cancel a running query, send the <literal>SIGINT</literal> signal
   to the process running that command.
  </para>

  <para>
   The <command>postgres</command> server uses <literal>SIGTERM</literal>
   to tell subordinate server processes to quit normally and
   <literal>SIGQUIT</literal> to terminate without the normal cleanup.
   These signals <emphasis>should not</emphasis> be used by users.  It
   is also unwise to send <literal>SIGKILL</literal> to a server
   process &mdash; the main <command>postgres</command> process will
   interpret this as a crash and will force all the sibling processes
   to quit as part of its standard crash-recovery procedure.
  </para>
 </refsect1>

 <refsect1 id="app-postgres-bugs">
  <title>Bugs</title>
  <para>
   The <option>--</> options will not work on <systemitem
   class="osname">FreeBSD</> or <systemitem class="osname">OpenBSD</>.
   Use <option>-c</> instead. This is a bug in the affected operating
   systems; a future release of <productname>PostgreSQL</productname>
   will provide a workaround if this is not fixed.
  </para>
 </refsect1>

 <refsect1>
  <title>Usage</title>

   <para>
    To start a single-user mode server, use a command like
<screen>
<userinput>postgres --single -D /usr/local/pgsql/data <replaceable>other-options</> my_database</userinput>
</screen>
    Provide the correct path to the database directory with <option>-D</>, or
    make sure that the environment variable <envar>PGDATA</> is set.
    Also specify the name of the particular database you want to work in.
   </para>

   <para>
    Normally, the single-user mode server treats newline as the command
    entry terminator; there is no intelligence about semicolons,
    as there is in <application>psql</>.  To continue a command
    across multiple lines, you must type backslash just before each
    newline except the last one.
   </para>

   <para>
    But if you use the <option>-j</> command line switch, then newline does
    not terminate command entry.  In this case, the server will read the standard input
    until the end-of-file (<acronym>EOF</>) marker, then
    process the input as a single command string.  Backslash-newline is not
    treated specially in this case.
   </para>

   <para>
    To quit the session, type <acronym>EOF</acronym>
    (<keycombo action="simul"><keycap>Control</><keycap>D</></>, usually).
    If you've
    used <option>-j</>, two consecutive <acronym>EOF</>s are needed to exit.
   </para>

   <para>
    Note that the single-user mode server does not provide sophisticated
    line-editing features (no command history, for example).
   </para>
 </refsect1>

 <refsect1 id="app-postgres-examples">
  <title>Examples</title>

  <para>
   To start <command>postgres</command> in the background
   using default values, type:

<screen>
<prompt>$</prompt> <userinput>nohup postgres &gt;logfile 2&gt;&amp;1 &lt;/dev/null &amp;</userinput>
</screen>
  </para>

  <para>
   To start <command>postgres</command> with a specific
   port:
<screen>
<prompt>$</prompt> <userinput>postgres -p 1234</userinput>
</screen>
   This command will start up <command>postgres</command>
   communicating through the port 1234. In order to connect to this
   server using <application>psql</>, you would need to run it as
<screen>
<prompt>$</prompt> <userinput>psql -p 1234</userinput>
</screen>
   or set the environment variable <envar>PGPORT</envar>:
<screen>
<prompt>$</prompt> <userinput>export PGPORT=1234</userinput>
<prompt>$</prompt> <userinput>psql</userinput>
</screen>
  </para>

  <para>
   Named run-time parameters can be set in either of these styles:
<screen>
<prompt>$</prompt> <userinput>postgres -c work_mem=1234</userinput>
<prompt>$</prompt> <userinput>postgres --work-mem=1234</userinput>
</screen>
   Either form overrides whatever setting might exist for
   <varname>work_mem</> in <filename>postgresql.conf</>.  Notice that
   underscores in parameter names can be written as either underscore
   or dash on the command line.  Except for short-term experiments,
   it's probably better practice to edit the setting in
   <filename>postgresql.conf</> than to rely on a command-line switch
   to set a parameter.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <para>
   <xref linkend="app-initdb">,
   <xref linkend="app-pg-ctl">
  </para>
 </refsect1>
</refentry>