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diff --git a/doc/src/sgml/html/server-start.html b/doc/src/sgml/html/server-start.html new file mode 100644 index 0000000..9975c2b --- /dev/null +++ b/doc/src/sgml/html/server-start.html @@ -0,0 +1,255 @@ +<?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>18.3. Starting the Database Server</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 V1.79.1" /><link rel="prev" href="creating-cluster.html" title="18.2. Creating a Database Cluster" /><link rel="next" href="kernel-resources.html" title="18.4. Managing Kernel Resources" /></head><body id="docContent" class="container-fluid col-10"><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">18.3. Starting the Database Server</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="creating-cluster.html" title="18.2. Creating a Database Cluster">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="runtime.html" title="Chapter 18. Server Setup and Operation">Up</a></td><th width="60%" align="center">Chapter 18. Server Setup and Operation</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 13.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="kernel-resources.html" title="18.4. Managing Kernel Resources">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="SERVER-START"><div class="titlepage"><div><div><h2 class="title" style="clear: both">18.3. Starting the Database Server</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="server-start.html#SERVER-START-FAILURES">18.3.1. Server Start-up Failures</a></span></dt><dt><span class="sect2"><a href="server-start.html#CLIENT-CONNECTION-PROBLEMS">18.3.2. Client Connection Problems</a></span></dt></dl></div><p> + Before anyone can access the database, you must start the database + server. The database server program is called + <code class="command">postgres</code>.<a id="id-1.6.5.6.2.2" class="indexterm"></a> + </p><p> + If you are using a pre-packaged version + of <span class="productname">PostgreSQL</span>, it almost certainly includes + provisions for running the server as a background task according to the + conventions of your operating system. Using the package's + infrastructure to start the server will be much less work than figuring + out how to do this yourself. Consult the package-level documentation + for details. + </p><p> + The bare-bones way to start the server manually is just to invoke + <code class="command">postgres</code> directly, specifying the location of the + data directory with the <code class="option">-D</code> option, for example: +</p><pre class="screen"> +$ <strong class="userinput"><code>postgres -D /usr/local/pgsql/data</code></strong> +</pre><p> + which will leave the server running in the foreground. This must be + done while logged into the <span class="productname">PostgreSQL</span> user + account. Without <code class="option">-D</code>, the server will try to use + the data directory named by the environment variable <code class="envar">PGDATA</code>. + If that variable is not provided either, it will fail. + </p><p> + Normally it is better to start <code class="command">postgres</code> in the + background. For this, use the usual Unix shell syntax: +</p><pre class="screen"> +$ <strong class="userinput"><code>postgres -D /usr/local/pgsql/data >logfile 2>&1 &</code></strong> +</pre><p> + It is important to store the server's <span class="systemitem">stdout</span> and + <span class="systemitem">stderr</span> output somewhere, as shown above. It will help + for auditing purposes and to diagnose problems. (See <a class="xref" href="logfile-maintenance.html" title="24.3. Log File Maintenance">Section 24.3</a> for a more thorough discussion of log + file handling.) + </p><p> + The <code class="command">postgres</code> program also takes a number of other + command-line options. For more information, see the + <a class="xref" href="app-postgres.html" title="postgres"><span class="refentrytitle"><span class="application">postgres</span></span></a> reference page + and <a class="xref" href="runtime-config.html" title="Chapter 19. Server Configuration">Chapter 19</a> below. + </p><p> + This shell syntax can get tedious quickly. Therefore the wrapper + program + <a class="xref" href="app-pg-ctl.html" title="pg_ctl"><span class="refentrytitle"><span class="application">pg_ctl</span></span></a><a id="id-1.6.5.6.7.2" class="indexterm"></a> + is provided to simplify some tasks. For example: +</p><pre class="programlisting"> +pg_ctl start -l logfile +</pre><p> + will start the server in the background and put the output into the + named log file. The <code class="option">-D</code> option has the same meaning + here as for <code class="command">postgres</code>. <code class="command">pg_ctl</code> + is also capable of stopping the server. + </p><p> + Normally, you will want to start the database server when the + computer boots.<a id="id-1.6.5.6.8.1" class="indexterm"></a> + Autostart scripts are operating-system-specific. + There are a few example scripts distributed with + <span class="productname">PostgreSQL</span> in the + <code class="filename">contrib/start-scripts</code> directory. Installing one will require + root privileges. + </p><p> + Different systems have different conventions for starting up daemons + at boot time. Many systems have a file + <code class="filename">/etc/rc.local</code> or + <code class="filename">/etc/rc.d/rc.local</code>. Others use <code class="filename">init.d</code> or + <code class="filename">rc.d</code> directories. Whatever you do, the server must be + run by the <span class="productname">PostgreSQL</span> user account + <span class="emphasis"><em>and not by root</em></span> or any other user. Therefore you + probably should form your commands using + <code class="literal">su postgres -c '...'</code>. For example: +</p><pre class="programlisting"> +su postgres -c 'pg_ctl start -D /usr/local/pgsql/data -l serverlog' +</pre><p> + </p><p> + Here are a few more operating-system-specific suggestions. (In each + case be sure to use the proper installation directory and user + name where we show generic values.) + + </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> + For <span class="productname">FreeBSD</span>, look at the file + <code class="filename">contrib/start-scripts/freebsd</code> in the + <span class="productname">PostgreSQL</span> source distribution. + <a id="id-1.6.5.6.10.1.1.1.4" class="indexterm"></a> + </p></li><li class="listitem"><p> + On <span class="productname">OpenBSD</span>, add the following lines + to the file <code class="filename">/etc/rc.local</code>: + <a id="id-1.6.5.6.10.1.2.1.3" class="indexterm"></a> +</p><pre class="programlisting"> +if [ -x /usr/local/pgsql/bin/pg_ctl -a -x /usr/local/pgsql/bin/postgres ]; then + su -l postgres -c '/usr/local/pgsql/bin/pg_ctl start -s -l /var/postgresql/log -D /usr/local/pgsql/data' + echo -n ' postgresql' +fi +</pre><p> + </p></li><li class="listitem"><p> + On <span class="productname">Linux</span> systems either add + <a id="id-1.6.5.6.10.1.3.1.2" class="indexterm"></a> +</p><pre class="programlisting"> +/usr/local/pgsql/bin/pg_ctl start -l logfile -D /usr/local/pgsql/data +</pre><p> + to <code class="filename">/etc/rc.d/rc.local</code> + or <code class="filename">/etc/rc.local</code> or look at the file + <code class="filename">contrib/start-scripts/linux</code> in the + <span class="productname">PostgreSQL</span> source distribution. + </p><p> + When using <span class="application">systemd</span>, you can use the following + service unit file (e.g., + at <code class="filename">/etc/systemd/system/postgresql.service</code>):<a id="id-1.6.5.6.10.1.3.2.3" class="indexterm"></a> +</p><pre class="programlisting"> +[Unit] +Description=PostgreSQL database server +Documentation=man:postgres(1) + +[Service] +Type=notify +User=postgres +ExecStart=/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data +ExecReload=/bin/kill -HUP $MAINPID +KillMode=mixed +KillSignal=SIGINT +TimeoutSec=0 + +[Install] +WantedBy=multi-user.target +</pre><p> + Using <code class="literal">Type=notify</code> requires that the server binary was + built with <code class="literal">configure --with-systemd</code>. + </p><p> + Consider carefully the timeout + setting. <span class="application">systemd</span> has a default timeout of 90 + seconds as of this writing and will kill a process that does not notify + readiness within that time. But a <span class="productname">PostgreSQL</span> + server that might have to perform crash recovery at startup could take + much longer to become ready. The suggested value of 0 disables the + timeout logic. + </p></li><li class="listitem"><p> + On <span class="productname">NetBSD</span>, use either the + <span class="productname">FreeBSD</span> or + <span class="productname">Linux</span> start scripts, depending on + preference. + <a id="id-1.6.5.6.10.1.4.1.4" class="indexterm"></a> + </p></li><li class="listitem"><p> + On <span class="productname">Solaris</span>, create a file called + <code class="filename">/etc/init.d/postgresql</code> that contains + the following line: + <a id="id-1.6.5.6.10.1.5.1.3" class="indexterm"></a> +</p><pre class="programlisting"> +su - postgres -c "/usr/local/pgsql/bin/pg_ctl start -l logfile -D /usr/local/pgsql/data" +</pre><p> + Then, create a symbolic link to it in <code class="filename">/etc/rc3.d</code> as + <code class="filename">S99postgresql</code>. + </p></li></ul></div><p> + + </p><p> + While the server is running, its + <acronym class="acronym">PID</acronym> is stored in the file + <code class="filename">postmaster.pid</code> in the data directory. This is + used to prevent multiple server instances from + running in the same data directory and can also be used for + shutting down the server. + </p><div class="sect2" id="SERVER-START-FAILURES"><div class="titlepage"><div><div><h3 class="title">18.3.1. Server Start-up Failures</h3></div></div></div><p> + There are several common reasons the server might fail to + start. Check the server's log file, or start it by hand (without + redirecting standard output or standard error) and see what error + messages appear. Below we explain some of the most common error + messages in more detail. + </p><p> +</p><pre class="screen"> +LOG: could not bind IPv4 address "127.0.0.1": Address already in use +HINT: Is another postmaster already running on port 5432? If not, wait a few seconds and retry. +FATAL: could not create any TCP/IP sockets +</pre><p> + This usually means just what it suggests: you tried to start + another server on the same port where one is already running. + However, if the kernel error message is not <code class="computeroutput">Address + already in use</code> or some variant of that, there might + be a different problem. For example, trying to start a server + on a reserved port number might draw something like: +</p><pre class="screen"> +$ <strong class="userinput"><code>postgres -p 666</code></strong> +LOG: could not bind IPv4 address "127.0.0.1": Permission denied +HINT: Is another postmaster already running on port 666? If not, wait a few seconds and retry. +FATAL: could not create any TCP/IP sockets +</pre><p> + </p><p> + A message like: +</p><pre class="screen"> +FATAL: could not create shared memory segment: Invalid argument +DETAIL: Failed system call was shmget(key=5440001, size=4011376640, 03600). +</pre><p> + probably means your kernel's limit on the size of shared memory is + smaller than the work area <span class="productname">PostgreSQL</span> + is trying to create (4011376640 bytes in this example). + This is only likely to happen if you have set <code class="literal">shared_memory_type</code> + to <code class="literal">sysv</code>. In that case, you + can try starting the server with a smaller-than-normal number of + buffers (<a class="xref" href="runtime-config-resource.html#GUC-SHARED-BUFFERS">shared_buffers</a>), or + reconfigure your kernel to increase the allowed shared memory + size. You might also see this message when trying to start multiple + servers on the same machine, if their total space requested + exceeds the kernel limit. + </p><p> + An error like: +</p><pre class="screen"> +FATAL: could not create semaphores: No space left on device +DETAIL: Failed system call was semget(5440126, 17, 03600). +</pre><p> + does <span class="emphasis"><em>not</em></span> mean you've run out of disk + space. It means your kernel's limit on the number of <span class="systemitem">System V</span> semaphores is smaller than the number + <span class="productname">PostgreSQL</span> wants to create. As above, + you might be able to work around the problem by starting the + server with a reduced number of allowed connections + (<a class="xref" href="runtime-config-connection.html#GUC-MAX-CONNECTIONS">max_connections</a>), but you'll eventually want to + increase the kernel limit. + </p><p> + Details about configuring <span class="systemitem">System V</span> + <acronym class="acronym">IPC</acronym> facilities are given in <a class="xref" href="kernel-resources.html#SYSVIPC" title="18.4.1. Shared Memory and Semaphores">Section 18.4.1</a>. + </p></div><div class="sect2" id="CLIENT-CONNECTION-PROBLEMS"><div class="titlepage"><div><div><h3 class="title">18.3.2. Client Connection Problems</h3></div></div></div><p> + Although the error conditions possible on the client side are quite + varied and application-dependent, a few of them might be directly + related to how the server was started. Conditions other than + those shown below should be documented with the respective client + application. + </p><p> +</p><pre class="screen"> +psql: could not connect to server: Connection refused + Is the server running on host "server.joe.com" and accepting + TCP/IP connections on port 5432? +</pre><p> + This is the generic <span class="quote">“<span class="quote">I couldn't find a server to talk + to</span>”</span> failure. It looks like the above when TCP/IP + communication is attempted. A common mistake is to forget to + configure the server to allow TCP/IP connections. + </p><p> + Alternatively, you'll get this when attempting Unix-domain socket + communication to a local server: +</p><pre class="screen"> +psql: could not connect to server: No such file or directory + Is the server running locally and accepting + connections on Unix domain socket "/tmp/.s.PGSQL.5432"? +</pre><p> + </p><p> + The last line is useful in verifying that the client is trying to + connect to the right place. If there is in fact no server + running there, the kernel error message will typically be either + <code class="computeroutput">Connection refused</code> or + <code class="computeroutput">No such file or directory</code>, as + illustrated. (It is important to realize that + <code class="computeroutput">Connection refused</code> in this context + does <span class="emphasis"><em>not</em></span> mean that the server got your + connection request and rejected it. That case will produce a + different message, as shown in <a class="xref" href="client-authentication-problems.html" title="20.15. Authentication Problems">Section 20.15</a>.) Other error messages + such as <code class="computeroutput">Connection timed out</code> might + indicate more fundamental problems, like lack of network + connectivity. + </p></div></div><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navfooter"><hr></hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="creating-cluster.html" title="18.2. Creating a Database Cluster">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="runtime.html" title="Chapter 18. Server Setup and Operation">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="kernel-resources.html" title="18.4. Managing Kernel Resources">Next</a></td></tr><tr><td width="40%" align="left" valign="top">18.2. 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