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<!-- doc/src/sgml/runtime.sgml -->
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<chapter id="runtime">
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<title>Server Setup and Operation</title>
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<para>
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This chapter discusses how to set up and run the database server
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and its interactions with the operating system.
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</para>
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<sect1 id="postgres-user">
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<title>The <productname>PostgreSQL</productname> User Account</title>
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<indexterm>
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<primary>postgres user</primary>
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</indexterm>
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<para>
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As with any server daemon that is accessible to the outside world,
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it is advisable to run <productname>PostgreSQL</productname> under a
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separate user account. This user account should only own the data
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that is managed by the server, and should not be shared with other
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daemons. (For example, using the user <literal>nobody</literal> is a bad
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idea.) It is not advisable to install executables owned by this
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user because compromised systems could then modify their own
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binaries.
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</para>
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<para>
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To add a Unix user account to your system, look for a command
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<command>useradd</command> or <command>adduser</command>. The user
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name <systemitem>postgres</systemitem> is often used, and is assumed
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throughout this book, but you can use another name if you like.
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</para>
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</sect1>
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<sect1 id="creating-cluster">
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<title>Creating a Database Cluster</title>
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<indexterm>
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<primary>database cluster</primary>
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</indexterm>
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<indexterm>
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<primary>data area</primary>
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<see>database cluster</see>
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</indexterm>
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<para>
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Before you can do anything, you must initialize a database storage
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area on disk. We call this a <firstterm>database cluster</firstterm>.
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(The <acronym>SQL</acronym> standard uses the term catalog cluster.) A
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database cluster is a collection of databases that is managed by a
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single instance of a running database server. After initialization, a
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database cluster will contain a database named <literal>postgres</literal>,
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which is meant as a default database for use by utilities, users and third
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party applications. The database server itself does not require the
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<literal>postgres</literal> database to exist, but many external utility
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programs assume it exists. Another database created within each cluster
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during initialization is called
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<literal>template1</literal>. As the name suggests, this will be used
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as a template for subsequently created databases; it should not be
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used for actual work. (See <xref linkend="managing-databases"> for
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information about creating new databases within a cluster.)
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</para>
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<para>
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In file system terms, a database cluster is a single directory
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under which all data will be stored. We call this the <firstterm>data
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directory</firstterm> or <firstterm>data area</firstterm>. It is
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completely up to you where you choose to store your data. There is no
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default, although locations such as
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<filename>/usr/local/pgsql/data</filename> or
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<filename>/var/lib/pgsql/data</filename> are popular. To initialize a
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database cluster, use the command <xref
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linkend="app-initdb">,<indexterm><primary>initdb</></> which is
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installed with <productname>PostgreSQL</productname>. The desired
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file system location of your database cluster is indicated by the
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<option>-D</option> option, for example:
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<screen>
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<prompt>$</> <userinput>initdb -D /usr/local/pgsql/data</userinput>
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</screen>
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Note that you must execute this command while logged into the
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<productname>PostgreSQL</productname> user account, which is
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described in the previous section.
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</para>
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<tip>
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<para>
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As an alternative to the <option>-D</option> option, you can set
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the environment variable <envar>PGDATA</envar>.
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<indexterm><primary><envar>PGDATA</envar></primary></indexterm>
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</para>
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</tip>
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2009-12-10 07:32:28 +01:00
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<para>
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Alternatively, you can run <command>initdb</command> via
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the <xref linkend="app-pg-ctl">
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program<indexterm><primary>pg_ctl</></> like so:
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<screen>
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<prompt>$</> <userinput>pg_ctl -D /usr/local/pgsql/data initdb</userinput>
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</screen>
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This may be more intuitive if you are
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using <command>pg_ctl</command> for starting and stopping the
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server (see <xref linkend="server-start">), so
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that <command>pg_ctl</command> would be the sole command you use
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for managing the database server instance.
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</para>
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<para>
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<command>initdb</command> will attempt to create the directory you
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specify if it does not already exist. Of course, this will fail if
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<command>initdb</command> does not have permissions to write in the
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parent directory. It's generally recommendable that the
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<productname>PostgreSQL</productname> user own not just the data
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directory but its parent directory as well, so that this should not
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be a problem. If the desired parent directory doesn't exist either,
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you will need to create it first, using root privileges if the
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grandparent directory isn't writable. So the process might look
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like this:
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<screen>
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root# <userinput>mkdir /usr/local/pgsql</userinput>
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root# <userinput>chown postgres /usr/local/pgsql</userinput>
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root# <userinput>su postgres</userinput>
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postgres$ <userinput>initdb -D /usr/local/pgsql/data</userinput>
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</screen>
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</para>
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<para>
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<command>initdb</command> will refuse to run if the data directory
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exists and already contains files; this is to prevent accidentally
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overwriting an existing installation.
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</para>
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<para>
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Because the data directory contains all the data stored in the
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database, it is essential that it be secured from unauthorized
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access. <command>initdb</command> therefore revokes access
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permissions from everyone but the
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<productname>PostgreSQL</productname> user.
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</para>
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2001-11-28 01:13:30 +01:00
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<para>
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However, while the directory contents are secure, the default
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client authentication setup allows any local user to connect to the
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database and even become the database superuser. If you do not
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trust other local users, we recommend you use one of
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<command>initdb</command>'s <option>-W</option>, <option>--pwprompt</option>
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or <option>--pwfile</option> options to assign a password to the
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database superuser.<indexterm>
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<primary>password</>
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<secondary>of the superuser</>
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</indexterm>
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Also, specify <option>-A md5</> or
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<option>-A password</> so that the default <literal>trust</> authentication
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mode is not used; or modify the generated <filename>pg_hba.conf</filename>
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file after running <command>initdb</command>, but
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<emphasis>before</> you start the server for the first time. (Other
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reasonable approaches include using <literal>peer</literal> authentication
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or file system permissions to restrict connections. See <xref
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linkend="client-authentication"> for more information.)
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</para>
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<para>
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<command>initdb</command> also initializes the default
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locale<indexterm><primary>locale</></> for the database cluster.
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Normally, it will just take the locale settings in the environment
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and apply them to the initialized database. It is possible to
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specify a different locale for the database; more information about
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that can be found in <xref linkend="locale">. The default sort order used
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within the particular database cluster is set by
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<command>initdb</command>, and while you can create new databases using
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different sort order, the order used in the template databases that initdb
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creates cannot be changed without dropping and recreating them.
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There is also a performance impact for using locales
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other than <literal>C</> or <literal>POSIX</>. Therefore, it is
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important to make this choice correctly the first time.
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</para>
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<para>
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<command>initdb</command> also sets the default character set encoding
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for the database cluster. Normally this should be chosen to match the
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locale setting. For details see <xref linkend="multibyte">.
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</para>
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2016-07-02 17:22:36 +02:00
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<para>
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Non-<literal>C</> and non-<literal>POSIX</> locales rely on the
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operating system's collation library for character set ordering.
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This controls the ordering of keys stored in indexes. For this reason,
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a cluster cannot switch to an incompatible collation library version,
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either through snapshot restore, binary streaming replication, a
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different operating system, or an operating system upgrade.
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</para>
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2015-07-29 00:42:59 +02:00
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<sect2 id="creating-cluster-mount-points">
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<title>Use of Secondary File Systems</title>
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<indexterm zone="creating-cluster-mount-points">
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<primary>file system mount points</primary>
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</indexterm>
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<para>
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Many installations create their database clusters on file systems
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(volumes) other than the machine's <quote>root</> volume. If you
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choose to do this, it is not advisable to try to use the secondary
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volume's topmost directory (mount point) as the data directory.
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Best practice is to create a directory within the mount-point
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directory that is owned by the <productname>PostgreSQL</productname>
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user, and then create the data directory within that. This avoids
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permissions problems, particularly for operations such
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as <application>pg_upgrade</>, and it also ensures clean failures if
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the secondary volume is taken offline.
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</para>
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</sect2>
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2007-11-08 16:21:03 +01:00
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<sect2 id="creating-cluster-nfs">
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<title>Use of Network File Systems</title>
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<indexterm zone="creating-cluster-nfs">
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<primary>Network File Systems</primary>
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</indexterm>
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<indexterm><primary><acronym>NFS</></><see>Network File Systems</></>
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<indexterm><primary>Network Attached Storage (<acronym>NAS</>)</><see>Network File Systems</></>
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<para>
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Many installations create their database clusters on network file
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systems. Sometimes this is done via <acronym>NFS</>, or by using a
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Network Attached Storage (<acronym>NAS</>) device that uses
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<acronym>NFS</> internally. <productname>PostgreSQL</> does nothing
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special for <acronym>NFS</> file systems, meaning it assumes
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<acronym>NFS</> behaves exactly like locally-connected drives.
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If the client or server <acronym>NFS</> implementation does not
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provide standard file system semantics, this can
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cause reliability problems (see <ulink
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url="http://www.time-travellers.org/shane/papers/NFS_considered_harmful.html"></ulink>).
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Specifically, delayed (asynchronous) writes to the <acronym>NFS</>
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server can cause data corruption problems. If possible, mount the
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<acronym>NFS</> file system synchronously (without caching) to avoid
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this hazard. Also, soft-mounting the <acronym>NFS</> file system is
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not recommended.
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</para>
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<para>
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Storage Area Networks (<acronym>SAN</>) typically use communication
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protocols other than <acronym>NFS</>, and may or may not be subject
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to hazards of this sort. It's advisable to consult the vendor's
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documentation concerning data consistency guarantees.
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<productname>PostgreSQL</productname> cannot be more reliable than
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the file system it's using.
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</para>
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</sect2>
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2000-06-18 23:24:54 +02:00
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</sect1>
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2006-06-18 17:38:37 +02:00
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<sect1 id="server-start">
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<title>Starting the Database Server</title>
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<para>
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Before anyone can access the database, you must start the database
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server. The database server program is called
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<command>postgres</command>.<indexterm><primary>postgres</></>
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The <command>postgres</command> program must know where to
|
2002-03-09 06:11:38 +01:00
|
|
|
find the data it is supposed to use. This is done with the
|
|
|
|
<option>-D</option> option. Thus, the simplest way to start the
|
|
|
|
server is:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2006-06-18 17:38:37 +02:00
|
|
|
$ <userinput>postgres -D /usr/local/pgsql/data</userinput>
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
2002-03-09 06:11:38 +01:00
|
|
|
which will leave the server running in the foreground. This must be
|
|
|
|
done while logged into the <productname>PostgreSQL</productname> user
|
|
|
|
account. Without <option>-D</option>, the server will try to use
|
2004-04-29 06:37:09 +02:00
|
|
|
the data directory named by the environment variable <envar>PGDATA</envar>.
|
|
|
|
If that variable is not provided either, it will fail.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2006-06-18 17:38:37 +02:00
|
|
|
Normally it is better to start <command>postgres</command> in the
|
2010-02-03 18:25:06 +01:00
|
|
|
background. For this, use the usual Unix shell syntax:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2006-06-18 17:38:37 +02:00
|
|
|
$ <userinput>postgres -D /usr/local/pgsql/data >logfile 2>&1 &</userinput>
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
2004-04-29 06:37:09 +02:00
|
|
|
It is important to store the server's <systemitem>stdout</> and
|
2002-03-09 06:11:38 +01:00
|
|
|
<systemitem>stderr</> output somewhere, as shown above. It will help
|
|
|
|
for auditing purposes and to diagnose problems. (See <xref
|
|
|
|
linkend="logfile-maintenance"> for a more thorough discussion of log
|
|
|
|
file handling.)
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2006-06-18 17:38:37 +02:00
|
|
|
The <command>postgres</command> program also takes a number of other
|
|
|
|
command-line options. For more information, see the
|
|
|
|
<xref linkend="app-postgres"> reference page
|
2004-03-23 02:23:48 +01:00
|
|
|
and <xref linkend="runtime-config"> below.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
2001-02-10 01:50:18 +01:00
|
|
|
<para>
|
2004-12-27 00:06:56 +01:00
|
|
|
This shell syntax can get tedious quickly. Therefore the wrapper
|
|
|
|
program
|
|
|
|
<xref linkend="app-pg-ctl"><indexterm><primary>pg_ctl</primary></indexterm>
|
2003-03-24 15:32:51 +01:00
|
|
|
is provided to simplify some tasks. For example:
|
2001-02-10 01:50:18 +01:00
|
|
|
<programlisting>
|
|
|
|
pg_ctl start -l logfile
|
|
|
|
</programlisting>
|
|
|
|
will start the server in the background and put the output into the
|
2002-03-09 06:11:38 +01:00
|
|
|
named log file. The <option>-D</option> option has the same meaning
|
2006-06-18 17:38:37 +02:00
|
|
|
here as for <command>postgres</command>. <command>pg_ctl</command>
|
2004-12-27 00:06:56 +01:00
|
|
|
is also capable of stopping the server.
|
2001-02-10 01:50:18 +01:00
|
|
|
</para>
|
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
<para>
|
|
|
|
Normally, you will want to start the database server when the
|
2011-04-08 17:36:05 +02:00
|
|
|
computer boots.<indexterm>
|
|
|
|
<primary>booting</>
|
|
|
|
<secondary>starting the server during</>
|
|
|
|
</indexterm>
|
|
|
|
Autostart scripts are operating-system-specific.
|
2004-04-29 06:37:09 +02:00
|
|
|
There are a few distributed with
|
2002-03-09 06:11:38 +01:00
|
|
|
<productname>PostgreSQL</productname> in the
|
2004-04-29 06:37:09 +02:00
|
|
|
<filename>contrib/start-scripts</> directory. Installing one will require
|
|
|
|
root privileges.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
Different systems have different conventions for starting up daemons
|
|
|
|
at boot time. Many systems have a file
|
2000-06-18 23:24:54 +02:00
|
|
|
<filename>/etc/rc.local</filename> or
|
2011-07-14 18:07:39 +02:00
|
|
|
<filename>/etc/rc.d/rc.local</filename>. Others use <filename>init.d</filename> or
|
2002-03-09 06:11:38 +01:00
|
|
|
<filename>rc.d</> directories. Whatever you do, the server must be
|
|
|
|
run by the <productname>PostgreSQL</productname> user account
|
|
|
|
<emphasis>and not by root</emphasis> or any other user. Therefore you
|
2012-09-25 19:52:53 +02:00
|
|
|
probably should form your commands using
|
|
|
|
<literal>su postgres -c '...'</literal>. For example:
|
2000-06-18 23:24:54 +02:00
|
|
|
<programlisting>
|
2012-09-25 19:52:53 +02:00
|
|
|
su postgres -c 'pg_ctl start -D /usr/local/pgsql/data -l serverlog'
|
2000-06-18 23:24:54 +02:00
|
|
|
</programlisting>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2004-04-29 06:37:09 +02:00
|
|
|
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.)
|
2000-06-18 23:24:54 +02:00
|
|
|
|
|
|
|
<itemizedlist>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
For <productname>FreeBSD</productname>, look at the file
|
2001-02-10 01:50:18 +01:00
|
|
|
<filename>contrib/start-scripts/freebsd</filename> in the
|
|
|
|
<productname>PostgreSQL</productname> source distribution.
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>FreeBSD</><secondary>start script</secondary></>
|
2001-02-10 01:50:18 +01:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
On <productname>OpenBSD</productname>, add the following lines
|
|
|
|
to the file <filename>/etc/rc.local</filename>:
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>OpenBSD</><secondary>start script</secondary></>
|
2000-06-18 23:24:54 +02:00
|
|
|
<programlisting>
|
2006-06-18 17:38:37 +02:00
|
|
|
if [ -x /usr/local/pgsql/bin/pg_ctl -a -x /usr/local/pgsql/bin/postgres ]; then
|
2012-09-25 19:52:53 +02:00
|
|
|
su -l postgres -c '/usr/local/pgsql/bin/pg_ctl start -s -l /var/postgresql/log -D /usr/local/pgsql/data'
|
2001-02-10 01:50:18 +01:00
|
|
|
echo -n ' postgresql'
|
|
|
|
fi
|
2000-06-18 23:24:54 +02:00
|
|
|
</programlisting>
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2001-02-10 01:50:18 +01:00
|
|
|
On <productname>Linux</productname> systems either add
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>Linux</><secondary>start script</secondary></>
|
2000-06-18 23:24:54 +02:00
|
|
|
<programlisting>
|
2001-02-10 01:50:18 +01:00
|
|
|
/usr/local/pgsql/bin/pg_ctl start -l logfile -D /usr/local/pgsql/data
|
2000-06-18 23:24:54 +02:00
|
|
|
</programlisting>
|
2011-07-14 18:07:39 +02:00
|
|
|
to <filename>/etc/rc.d/rc.local</filename>
|
|
|
|
or <filename>/etc/rc.local</filename> or look at the file
|
2001-02-10 01:50:18 +01:00
|
|
|
<filename>contrib/start-scripts/linux</filename> in the
|
2002-03-09 06:11:38 +01:00
|
|
|
<productname>PostgreSQL</productname> source distribution.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
2015-11-17 12:46:17 +01:00
|
|
|
|
|
|
|
<para>
|
|
|
|
When using <application>systemd</application>, you can use the following
|
|
|
|
service unit file (e.g.,
|
|
|
|
at <filename>/etc/systemd/system/postgresql.service</filename>):<indexterm><primary>systemd</primary></indexterm>
|
|
|
|
<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
|
|
|
|
</programlisting>
|
|
|
|
Using <literal>Type=notify</literal> requires that the server binary was
|
|
|
|
built with <literal>configure --with-systemd</literal>.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Consider carefully the timeout
|
|
|
|
setting. <application>systemd</application> 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 <productname>PostgreSQL</productname>
|
|
|
|
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.
|
|
|
|
</para>
|
2000-06-18 23:24:54 +02:00
|
|
|
</listitem>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2011-12-01 02:55:00 +01:00
|
|
|
On <productname>NetBSD</productname>, use either the
|
2001-02-10 01:50:18 +01:00
|
|
|
<productname>FreeBSD</productname> or
|
|
|
|
<productname>Linux</productname> start scripts, depending on
|
2011-12-01 02:55:00 +01:00
|
|
|
preference.
|
|
|
|
<indexterm><primary>NetBSD</><secondary>start script</secondary></>
|
2001-02-10 01:50:18 +01:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2001-05-07 17:55:27 +02:00
|
|
|
On <productname>Solaris</productname>, create a file called
|
2003-03-24 15:32:51 +01:00
|
|
|
<filename>/etc/init.d/postgresql</filename> that contains
|
2002-03-09 06:11:38 +01:00
|
|
|
the following line:
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>Solaris</><secondary>start script</secondary></>
|
2001-02-10 01:50:18 +01:00
|
|
|
<programlisting>
|
|
|
|
su - postgres -c "/usr/local/pgsql/bin/pg_ctl start -l logfile -D /usr/local/pgsql/data"
|
|
|
|
</programlisting>
|
2001-09-10 01:52:12 +02:00
|
|
|
Then, create a symbolic link to it in <filename>/etc/rc3.d</> as
|
2003-03-24 15:32:51 +01:00
|
|
|
<filename>S99postgresql</>.
|
2001-02-10 01:50:18 +01:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</itemizedlist>
|
|
|
|
|
|
|
|
</para>
|
1999-05-20 07:39:29 +02:00
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
<para>
|
2006-06-18 17:38:37 +02:00
|
|
|
While the server is running, its
|
2003-03-24 15:32:51 +01:00
|
|
|
<acronym>PID</acronym> is stored in the file
|
2002-03-09 06:11:38 +01:00
|
|
|
<filename>postmaster.pid</filename> in the data directory. This is
|
2006-06-18 17:38:37 +02:00
|
|
|
used to prevent multiple server instances from
|
2003-03-24 15:32:51 +01:00
|
|
|
running in the same data directory and can also be used for
|
2006-06-18 17:38:37 +02:00
|
|
|
shutting down the server.
|
1999-05-20 07:39:29 +02:00
|
|
|
</para>
|
|
|
|
|
2006-06-18 17:38:37 +02:00
|
|
|
<sect2 id="server-start-failures">
|
2000-08-29 22:02:09 +02:00
|
|
|
<title>Server Start-up Failures</title>
|
2000-06-18 23:24:54 +02:00
|
|
|
|
|
|
|
<para>
|
2003-03-24 15:32:51 +01:00
|
|
|
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.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<screen>
|
2003-09-13 00:17:24 +02:00
|
|
|
LOG: could not bind IPv4 socket: 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 TCP/IP listen socket
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
2002-03-09 06:11:38 +01:00
|
|
|
This usually means just what it suggests: you tried to start
|
2006-06-18 17:38:37 +02:00
|
|
|
another server on the same port where one is already running.
|
2002-03-09 06:11:38 +01:00
|
|
|
However, if the kernel error message is not <computeroutput>Address
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
already in use</computeroutput> or some variant of that, there might
|
2006-06-18 17:38:37 +02:00
|
|
|
be a different problem. For example, trying to start a server
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
on a reserved port number might draw something like:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2006-06-18 17:38:37 +02:00
|
|
|
$ <userinput>postgres -p 666</userinput>
|
2003-09-13 00:17:24 +02:00
|
|
|
LOG: could not bind IPv4 socket: Permission denied
|
|
|
|
HINT: Is another postmaster already running on port 666? If not, wait a few seconds and retry.
|
|
|
|
FATAL: could not create TCP/IP listen socket
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2009-04-27 18:27:36 +02:00
|
|
|
A message like:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2003-09-13 00:17:24 +02:00
|
|
|
FATAL: could not create shared memory segment: Invalid argument
|
2003-11-04 10:55:39 +01:00
|
|
|
DETAIL: Failed system call was shmget(key=5440001, size=4011376640, 03600).
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
2002-03-09 06:11:38 +01:00
|
|
|
probably means your kernel's limit on the size of shared memory is
|
2003-09-13 00:17:24 +02:00
|
|
|
smaller than the work area <productname>PostgreSQL</productname>
|
|
|
|
is trying to create (4011376640 bytes in this example). Or it could
|
2003-02-19 05:06:28 +01:00
|
|
|
mean that you do not have System-V-style shared memory support
|
2002-03-09 06:11:38 +01:00
|
|
|
configured into your kernel at all. As a temporary workaround, you
|
2005-08-30 17:48:28 +02:00
|
|
|
can try starting the server with a smaller-than-normal number of
|
|
|
|
buffers (<xref linkend="guc-shared-buffers">). You will eventually want
|
2002-03-09 06:11:38 +01:00
|
|
|
to reconfigure your kernel to increase the allowed shared memory
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
size. You might also see this message when trying to start multiple
|
2003-09-13 00:17:24 +02:00
|
|
|
servers on the same machine, if their total space requested
|
2002-03-09 06:11:38 +01:00
|
|
|
exceeds the kernel limit.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2009-04-27 18:27:36 +02:00
|
|
|
An error like:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2003-09-13 00:17:24 +02:00
|
|
|
FATAL: could not create semaphores: No space left on device
|
2003-11-04 10:55:39 +01:00
|
|
|
DETAIL: Failed system call was semget(5440126, 17, 03600).
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
2003-01-11 06:04:14 +01:00
|
|
|
does <emphasis>not</emphasis> mean you've run out of disk
|
|
|
|
space. It means your kernel's limit on the number of <systemitem
|
|
|
|
class="osname">System V</> semaphores is smaller than the number
|
|
|
|
<productname>PostgreSQL</productname> wants to create. As above,
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
you might be able to work around the problem by starting the
|
2003-03-24 15:32:51 +01:00
|
|
|
server with a reduced number of allowed connections
|
2005-08-30 17:48:28 +02:00
|
|
|
(<xref linkend="guc-max-connections">), but you'll eventually want to
|
2000-06-18 23:24:54 +02:00
|
|
|
increase the kernel limit.
|
|
|
|
</para>
|
2000-07-22 16:49:01 +02:00
|
|
|
|
2000-08-26 21:34:24 +02:00
|
|
|
<para>
|
2002-11-11 21:14:04 +01:00
|
|
|
If you get an <quote>illegal system call</> error, it is likely that
|
2002-03-09 06:11:38 +01:00
|
|
|
shared memory or semaphores are not supported in your kernel at
|
|
|
|
all. In that case your only option is to reconfigure the kernel to
|
|
|
|
enable these features.
|
2000-08-26 21:34:24 +02:00
|
|
|
</para>
|
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
Details about configuring <systemitem class="osname">System V</>
|
|
|
|
<acronym>IPC</> facilities are given in <xref linkend="sysvipc">.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
2000-06-18 23:24:54 +02:00
|
|
|
</sect2>
|
|
|
|
|
|
|
|
<sect2 id="client-connection-problems">
|
|
|
|
<title>Client Connection Problems</title>
|
|
|
|
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
Although the error conditions possible on the client side are quite
|
|
|
|
varied and application-dependent, a few of them might be directly
|
2010-02-03 18:25:06 +01:00
|
|
|
related to how the server was started. Conditions other than
|
2002-03-09 06:11:38 +01:00
|
|
|
those shown below should be documented with the respective client
|
|
|
|
application.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<screen>
|
2001-07-15 15:45:04 +02:00
|
|
|
psql: could not connect to server: Connection refused
|
2003-09-13 00:17:24 +02:00
|
|
|
Is the server running on host "server.joe.com" and accepting
|
2001-07-15 15:45:04 +02:00
|
|
|
TCP/IP connections on port 5432?
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
|
|
|
This is the generic <quote>I couldn't find a server to talk
|
|
|
|
to</quote> failure. It looks like the above when TCP/IP
|
2003-03-24 15:32:51 +01:00
|
|
|
communication is attempted. A common mistake is to forget to
|
|
|
|
configure the server to allow TCP/IP connections.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2003-03-24 15:32:51 +01:00
|
|
|
Alternatively, you'll get this when attempting Unix-domain socket
|
|
|
|
communication to a local server:
|
2000-06-18 23:24:54 +02:00
|
|
|
<screen>
|
2003-09-13 00:17:24 +02:00
|
|
|
psql: could not connect to server: No such file or directory
|
2001-07-15 15:45:04 +02:00
|
|
|
Is the server running locally and accepting
|
|
|
|
connections on Unix domain socket "/tmp/.s.PGSQL.5432"?
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The last line is useful in verifying that the client is trying to
|
2003-03-24 15:32:51 +01:00
|
|
|
connect to the right place. If there is in fact no server
|
2002-03-09 06:11:38 +01:00
|
|
|
running there, the kernel error message will typically be either
|
|
|
|
<computeroutput>Connection refused</computeroutput> or
|
2000-06-18 23:24:54 +02:00
|
|
|
<computeroutput>No such file or directory</computeroutput>, as
|
2002-03-09 06:11:38 +01:00
|
|
|
illustrated. (It is important to realize that
|
|
|
|
<computeroutput>Connection refused</computeroutput> in this context
|
2003-03-24 15:32:51 +01:00
|
|
|
does <emphasis>not</emphasis> mean that the server got your
|
|
|
|
connection request and rejected it. That case will produce a
|
2002-03-09 06:11:38 +01:00
|
|
|
different message, as shown in <xref
|
2000-06-18 23:24:54 +02:00
|
|
|
linkend="client-authentication-problems">.) Other error messages
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
such as <computeroutput>Connection timed out</computeroutput> might
|
2000-06-18 23:24:54 +02:00
|
|
|
indicate more fundamental problems, like lack of network
|
|
|
|
connectivity.
|
|
|
|
</para>
|
|
|
|
</sect2>
|
1999-05-20 07:39:29 +02:00
|
|
|
</sect1>
|
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<sect1 id="kernel-resources">
|
|
|
|
<title>Managing Kernel Resources</title>
|
|
|
|
|
|
|
|
<para>
|
2012-07-04 21:56:12 +02:00
|
|
|
<productname>PostgreSQL</> can sometimes exhaust various operating system
|
|
|
|
resource limits, especially when multiple copies of the server are running
|
|
|
|
on the same system, or in very large installations. This section explains
|
|
|
|
the kernel resources used by <productname>PostgreSQL</> and the steps you
|
|
|
|
can take to resolve problems related to kernel resource consumption.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<sect2 id="sysvipc">
|
|
|
|
<title>Shared Memory and Semaphores</title>
|
|
|
|
|
2001-05-13 00:51:36 +02:00
|
|
|
<indexterm zone="sysvipc">
|
|
|
|
<primary>shared memory</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<indexterm zone="sysvipc">
|
|
|
|
<primary>semaphores</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<para>
|
|
|
|
Shared memory and semaphores are collectively referred to as
|
2002-03-09 06:11:38 +01:00
|
|
|
<quote><systemitem class="osname">System V</>
|
|
|
|
<acronym>IPC</></quote> (together with message queues, which are not
|
2012-07-04 21:56:12 +02:00
|
|
|
relevant for <productname>PostgreSQL</>). Except on
|
|
|
|
<systemitem class="osname">Windows</>, where <productname>PostgreSQL</>
|
|
|
|
provides its own replacement implementation of these facilities, these
|
|
|
|
facilities are required in order to run
|
|
|
|
<productname>PostgreSQL</>.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The complete lack of these facilities is usually manifested by an
|
2003-03-24 15:32:51 +01:00
|
|
|
<errorname>Illegal system call</> error upon server start. In
|
2010-02-03 18:25:06 +01:00
|
|
|
that case there is no alternative but to reconfigure your
|
2003-03-24 15:32:51 +01:00
|
|
|
kernel. <productname>PostgreSQL</> won't work without them.
|
2010-03-13 12:00:19 +01:00
|
|
|
This situation is rare, however, among modern operating systems.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2001-11-21 07:09:45 +01:00
|
|
|
When <productname>PostgreSQL</> exceeds one of the various hard
|
2003-03-24 15:32:51 +01:00
|
|
|
<acronym>IPC</> limits, the server will refuse to start and
|
2002-03-09 06:11:38 +01:00
|
|
|
should leave an instructive error message describing the problem
|
2010-02-03 18:25:06 +01:00
|
|
|
and what to do about it. (See also <xref
|
2006-06-18 17:38:37 +02:00
|
|
|
linkend="server-start-failures">.) The relevant kernel
|
2002-03-09 06:11:38 +01:00
|
|
|
parameters are named consistently across different systems; <xref
|
|
|
|
linkend="sysvipc-parameters"> gives an overview. The methods to set
|
|
|
|
them, however, vary. Suggestions for some platforms are given below.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
2012-07-04 21:56:12 +02:00
|
|
|
<note>
|
|
|
|
<para>
|
|
|
|
Prior to <productname>PostgreSQL</> 9.3, the amount of System V shared
|
|
|
|
memory required to start the server was much larger. If you are running
|
|
|
|
an older version of the server, please consult the documentation for
|
|
|
|
your server version.
|
|
|
|
</para>
|
|
|
|
</note>
|
2000-07-22 16:49:01 +02:00
|
|
|
|
|
|
|
<table id="sysvipc-parameters">
|
2011-01-29 19:00:18 +01:00
|
|
|
<title><systemitem class="osname">System V</> <acronym>IPC</> Parameters</title>
|
2000-07-22 16:49:01 +02:00
|
|
|
|
|
|
|
<tgroup cols="3">
|
|
|
|
<thead>
|
|
|
|
<row>
|
|
|
|
<entry>Name</>
|
|
|
|
<entry>Description</>
|
|
|
|
<entry>Reasonable values</>
|
|
|
|
</row>
|
|
|
|
</thead>
|
|
|
|
|
|
|
|
<tbody>
|
|
|
|
<row>
|
|
|
|
<entry><varname>SHMMAX</></>
|
|
|
|
<entry>Maximum size of shared memory segment (bytes)</>
|
2012-07-04 21:56:12 +02:00
|
|
|
<entry>at least 1kB (more if running many copies of the server)</entry>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SHMMIN</></>
|
|
|
|
<entry>Minimum size of shared memory segment (bytes)</>
|
2001-05-03 19:28:13 +02:00
|
|
|
<entry>1</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
2001-05-02 19:04:53 +02:00
|
|
|
<row>
|
|
|
|
<entry><varname>SHMALL</></>
|
|
|
|
<entry>Total amount of shared memory available (bytes or pages)</>
|
2001-09-10 01:52:12 +02:00
|
|
|
<entry>if bytes, same as <varname>SHMMAX</varname>; if pages, <literal>ceil(SHMMAX/PAGE_SIZE)</literal></>
|
2001-05-02 19:04:53 +02:00
|
|
|
</row>
|
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<row>
|
|
|
|
<entry><varname>SHMSEG</></>
|
|
|
|
<entry>Maximum number of shared memory segments per process</>
|
2000-12-17 12:22:00 +01:00
|
|
|
<entry>only 1 segment is needed, but the default is much higher</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SHMMNI</></>
|
|
|
|
<entry>Maximum number of shared memory segments system-wide</>
|
2001-05-03 19:28:13 +02:00
|
|
|
<entry>like <varname>SHMSEG</> plus room for other applications</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SEMMNI</></>
|
|
|
|
<entry>Maximum number of semaphore identifiers (i.e., sets)</>
|
2016-02-16 06:49:47 +01:00
|
|
|
<entry>at least <literal>ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16)</literal></>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SEMMNS</></>
|
|
|
|
<entry>Maximum number of semaphores system-wide</>
|
2016-02-16 06:49:47 +01:00
|
|
|
<entry><literal>ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16) * 17</literal> plus room for other applications</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SEMMSL</></>
|
|
|
|
<entry>Maximum number of semaphores per set</>
|
2003-03-24 15:32:51 +01:00
|
|
|
<entry>at least 17</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SEMMAP</></>
|
|
|
|
<entry>Number of entries in semaphore map</>
|
|
|
|
<entry>see text</>
|
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
|
|
|
<entry><varname>SEMVMX</></>
|
|
|
|
<entry>Maximum value of semaphore</>
|
2010-02-03 18:25:06 +01:00
|
|
|
<entry>at least 1000 (The default is often 32767; do not change unless necessary)</>
|
2000-07-22 16:49:01 +02:00
|
|
|
</row>
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
</tgroup>
|
|
|
|
</table>
|
|
|
|
|
|
|
|
<para>
|
2012-07-04 21:56:12 +02:00
|
|
|
<productname>PostgreSQL</> requires a few bytes of System V shared memory
|
|
|
|
(typically 48 bytes, on 64-bit platforms) for each copy of the server.
|
|
|
|
On most modern operating systems, this amount can easily be allocated.
|
|
|
|
However, if you are running many copies of the server, or if other
|
|
|
|
applications are also using System V shared memory, it may be necessary
|
|
|
|
to increase <varname>SHMMAX</>, the maximum size in bytes of a shared
|
|
|
|
memory segment, or <varname>SHMALL</>, the total amount of System V shared
|
|
|
|
memory system-wide. Note that <varname>SHMALL</> is measured in pages
|
|
|
|
rather than bytes on many systems.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Less likely to cause problems is the minimum size for shared
|
2000-12-17 12:22:00 +01:00
|
|
|
memory segments (<varname>SHMMIN</>), which should be at most
|
2012-07-04 21:56:12 +02:00
|
|
|
approximately 32 bytes for <productname>PostgreSQL</> (it is
|
2000-12-17 12:22:00 +01:00
|
|
|
usually just 1). The maximum number of segments system-wide
|
2004-12-27 00:06:56 +01:00
|
|
|
(<varname>SHMMNI</>) or per-process (<varname>SHMSEG</>) are unlikely
|
|
|
|
to cause a problem unless your system has them set to zero.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2001-11-21 07:09:45 +01:00
|
|
|
<productname>PostgreSQL</> uses one semaphore per allowed connection
|
2016-02-16 06:49:47 +01:00
|
|
|
(<xref linkend="guc-max-connections">), allowed autovacuum worker process
|
|
|
|
(<xref linkend="guc-autovacuum-max-workers">) and allowed background
|
|
|
|
process (<xref linkend="guc-max-worker-processes">), in sets of 16.
|
2007-11-01 20:06:01 +01:00
|
|
|
Each such set will
|
2005-08-30 02:58:48 +02:00
|
|
|
also contain a 17th semaphore which contains a <quote>magic
|
2001-09-07 02:46:42 +02:00
|
|
|
number</quote>, to detect collision with semaphore sets used by
|
2000-12-17 12:22:00 +01:00
|
|
|
other applications. The maximum number of semaphores in the system
|
|
|
|
is set by <varname>SEMMNS</>, which consequently must be at least
|
2007-11-01 20:06:01 +01:00
|
|
|
as high as <varname>max_connections</> plus
|
2016-02-16 06:49:47 +01:00
|
|
|
<varname>autovacuum_max_workers</> plus <varname>max_worker_processes</>,
|
|
|
|
plus one extra for each 16
|
2007-11-01 20:06:01 +01:00
|
|
|
allowed connections plus workers (see the formula in <xref
|
2001-03-24 01:24:26 +01:00
|
|
|
linkend="sysvipc-parameters">). The parameter <varname>SEMMNI</>
|
2000-12-17 12:22:00 +01:00
|
|
|
determines the limit on the number of semaphore sets that can
|
|
|
|
exist on the system at one time. Hence this parameter must be at
|
2016-02-16 06:49:47 +01:00
|
|
|
least <literal>ceil((max_connections + autovacuum_max_workers + max_worker_processes + 5) / 16)</>.
|
2007-11-01 20:06:01 +01:00
|
|
|
Lowering the number
|
2000-12-17 12:22:00 +01:00
|
|
|
of allowed connections is a temporary workaround for failures,
|
2010-02-03 18:25:06 +01:00
|
|
|
which are usually confusingly worded <quote>No space
|
2003-03-24 15:32:51 +01:00
|
|
|
left on device</>, from the function <function>semget</>.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
In some cases it might also be necessary to increase
|
2000-07-22 16:49:01 +02:00
|
|
|
<varname>SEMMAP</> to be at least on the order of
|
2002-03-09 06:11:38 +01:00
|
|
|
<varname>SEMMNS</>. This parameter defines the size of the semaphore
|
|
|
|
resource map, in which each contiguous block of available semaphores
|
|
|
|
needs an entry. When a semaphore set is freed it is either added to
|
|
|
|
an existing entry that is adjacent to the freed block or it is
|
|
|
|
registered under a new map entry. If the map is full, the freed
|
|
|
|
semaphores get lost (until reboot). Fragmentation of the semaphore
|
|
|
|
space could over time lead to fewer available semaphores than there
|
|
|
|
should be.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The <varname>SEMMSL</> parameter, which determines how many
|
2000-12-17 12:22:00 +01:00
|
|
|
semaphores can be in a set, must be at least 17 for
|
2001-11-21 07:09:45 +01:00
|
|
|
<productname>PostgreSQL</>.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2000-11-10 17:32:09 +01:00
|
|
|
Various other settings related to <quote>semaphore undo</>, such as
|
2010-02-03 18:25:06 +01:00
|
|
|
<varname>SEMMNU</> and <varname>SEMUME</>, do not affect
|
|
|
|
<productname>PostgreSQL</>.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
2005-08-30 02:58:48 +02:00
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<variablelist>
|
2007-03-06 10:59:22 +01:00
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">AIX</>
|
2007-03-06 10:59:22 +01:00
|
|
|
<indexterm><primary>AIX</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2007-03-06 10:59:22 +01:00
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
At least as of version 5.1, it should not be necessary to do
|
|
|
|
any special configuration for such parameters as
|
|
|
|
<varname>SHMMAX</varname>, as it appears this is configured to
|
|
|
|
allow all memory to be used as shared memory. That is the
|
|
|
|
sort of configuration commonly used for other databases such
|
|
|
|
as <application>DB/2</application>.</para>
|
|
|
|
|
2007-11-01 20:06:01 +01:00
|
|
|
<para> It might, however, be necessary to modify the global
|
2007-03-06 10:59:22 +01:00
|
|
|
<command>ulimit</command> information in
|
|
|
|
<filename>/etc/security/limits</filename>, as the default hard
|
|
|
|
limits for file sizes (<varname>fsize</varname>) and numbers of
|
|
|
|
files (<varname>nofiles</varname>) might be too low.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
2010-05-27 01:49:19 +02:00
|
|
|
</varlistentry>
|
2000-07-22 16:49:01 +02:00
|
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">FreeBSD</>
|
2005-02-10 06:14:58 +01:00
|
|
|
<indexterm><primary>FreeBSD</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2005-02-10 06:14:58 +01:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2012-09-25 19:52:53 +02:00
|
|
|
The default settings can be changed using
|
2012-07-04 21:56:12 +02:00
|
|
|
the <command>sysctl</command> or
|
2005-02-10 06:14:58 +01:00
|
|
|
<command>loader</command> interfaces. The following
|
|
|
|
parameters can be set using <command>sysctl</command>:
|
|
|
|
<screen>
|
2012-08-27 05:21:45 +02:00
|
|
|
<prompt>#</prompt> <userinput>sysctl kern.ipc.shmall=32768</userinput>
|
|
|
|
<prompt>#</prompt> <userinput>sysctl kern.ipc.shmmax=134217728</userinput>
|
2005-02-10 06:14:58 +01:00
|
|
|
</screen>
|
2014-08-14 22:05:46 +02:00
|
|
|
To make these settings persist over reboots, modify
|
2005-02-10 06:14:58 +01:00
|
|
|
<filename>/etc/sysctl.conf</filename>.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2014-08-14 22:05:46 +02:00
|
|
|
These semaphore-related settings are read-only as far as
|
2012-08-27 05:21:45 +02:00
|
|
|
<command>sysctl</command> is concerned, but can be set in
|
|
|
|
<filename>/boot/loader.conf</filename>:
|
|
|
|
<programlisting>
|
|
|
|
kern.ipc.semmni=256
|
|
|
|
kern.ipc.semmns=512
|
|
|
|
kern.ipc.semmnu=256
|
|
|
|
</programlisting>
|
|
|
|
After modifying these values a reboot is required for the new
|
2014-08-14 22:05:46 +02:00
|
|
|
settings to take effect.
|
|
|
|
(Note: FreeBSD does not use <varname>SEMMAP</>. Older versions
|
|
|
|
would accept but ignore a setting for <literal>kern.ipc.semmap</>;
|
|
|
|
newer versions reject it altogether.)
|
2005-02-10 06:14:58 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
You might also want to configure your kernel to lock shared
|
|
|
|
memory into RAM and prevent it from being paged out to swap.
|
|
|
|
This can be accomplished using the <command>sysctl</command>
|
|
|
|
setting <literal>kern.ipc.shm_use_phys</literal>.
|
|
|
|
</para>
|
|
|
|
|
2006-04-11 21:26:42 +02:00
|
|
|
<para>
|
2006-04-11 23:04:52 +02:00
|
|
|
If running in FreeBSD jails by enabling <application>sysctl</>'s
|
2006-04-11 21:26:42 +02:00
|
|
|
<literal>security.jail.sysvipc_allowed</>, <application>postmaster</>s
|
|
|
|
running in different jails should be run by different operating system
|
2006-04-11 21:42:27 +02:00
|
|
|
users. This improves security because it prevents non-root users
|
2010-02-03 18:25:06 +01:00
|
|
|
from interfering with shared memory or semaphores in different jails,
|
2006-04-11 21:45:33 +02:00
|
|
|
and it allows the PostgreSQL IPC cleanup code to function properly.
|
2010-02-03 18:25:06 +01:00
|
|
|
(In FreeBSD 6.0 and later the IPC cleanup code does not properly detect
|
2006-04-11 21:26:42 +02:00
|
|
|
processes in other jails, preventing the running of postmasters on the
|
|
|
|
same port in different jails.)
|
|
|
|
</para>
|
|
|
|
|
2005-02-10 06:14:58 +01:00
|
|
|
<para>
|
2010-11-23 21:27:50 +01:00
|
|
|
<systemitem class="osname">FreeBSD</> versions before 4.0 work like
|
2011-12-01 02:55:00 +01:00
|
|
|
<systemitem class="osname">OpenBSD</> (see below).
|
2005-02-10 06:14:58 +01:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">NetBSD</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>NetBSD</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2011-12-01 02:55:00 +01:00
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
In <systemitem class="osname">NetBSD</> 5.0 and later,
|
|
|
|
IPC parameters can be adjusted using <command>sysctl</command>,
|
|
|
|
for example:
|
|
|
|
<screen>
|
|
|
|
<prompt>$</prompt> <userinput>sysctl -w kern.ipc.shmmax=16777216</userinput>
|
|
|
|
</screen>
|
|
|
|
To have these settings persist over reboots, modify
|
|
|
|
<filename>/etc/sysctl.conf</filename>.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
You might also want to configure your kernel to lock shared
|
|
|
|
memory into RAM and prevent it from being paged out to swap.
|
|
|
|
This can be accomplished using the <command>sysctl</command>
|
|
|
|
setting <literal>kern.ipc.shm_use_phys</literal>.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<systemitem class="osname">NetBSD</> versions before 5.0 work like
|
|
|
|
<systemitem class="osname">OpenBSD</> (see below), except that
|
|
|
|
parameters should be set with the keyword <literal>options</> not
|
|
|
|
<literal>option</>.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">OpenBSD</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>OpenBSD</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The options <varname>SYSVSHM</> and <varname>SYSVSEM</> need
|
|
|
|
to be enabled when the kernel is compiled. (They are by
|
|
|
|
default.) The maximum size of shared memory is determined by
|
|
|
|
the option <varname>SHMMAXPGS</> (in pages). The following
|
2011-12-01 02:55:00 +01:00
|
|
|
shows an example of how to set the various parameters:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
2011-12-01 02:55:00 +01:00
|
|
|
option SYSVSHM
|
|
|
|
option SHMMAXPGS=4096
|
|
|
|
option SHMSEG=256
|
|
|
|
|
|
|
|
option SYSVSEM
|
|
|
|
option SEMMNI=256
|
|
|
|
option SEMMNS=512
|
|
|
|
option SEMMNU=256
|
|
|
|
option SEMMAP=256
|
2000-07-22 16:49:01 +02:00
|
|
|
</programlisting>
|
|
|
|
</para>
|
2005-02-10 06:14:58 +01:00
|
|
|
|
2002-03-09 06:11:38 +01:00
|
|
|
<para>
|
2003-11-04 10:55:39 +01:00
|
|
|
You might also want to configure your kernel to lock shared
|
|
|
|
memory into RAM and prevent it from being paged out to swap.
|
2005-02-10 06:14:58 +01:00
|
|
|
This can be accomplished using the <command>sysctl</command>
|
|
|
|
setting <literal>kern.ipc.shm_use_phys</literal>.
|
2002-03-11 06:03:52 +01:00
|
|
|
</para>
|
2000-07-22 16:49:01 +02:00
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">HP-UX</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>HP-UX</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The default settings tend to suffice for normal installations.
|
2000-12-17 12:22:00 +01:00
|
|
|
On <productname>HP-UX</> 10, the factory default for
|
2000-07-22 16:49:01 +02:00
|
|
|
<varname>SEMMNS</> is 128, which might be too low for larger
|
|
|
|
database sites.
|
|
|
|
</para>
|
|
|
|
<para>
|
2001-09-10 01:52:12 +02:00
|
|
|
<acronym>IPC</> parameters can be set in the <application>System
|
2000-07-22 16:49:01 +02:00
|
|
|
Administration Manager</> (<acronym>SAM</>) under
|
|
|
|
<menuchoice><guimenu>Kernel
|
2010-02-03 18:25:06 +01:00
|
|
|
Configuration</><guimenuitem>Configurable Parameters</></>. Choose
|
2002-03-09 06:11:38 +01:00
|
|
|
<guibutton>Create A New Kernel</> when you're done.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">Linux</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>Linux</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2016-08-05 20:35:09 +02:00
|
|
|
The default maximum segment size is 32 MB, and the
|
2012-07-04 21:56:12 +02:00
|
|
|
default maximum total size is 2097152
|
2010-03-13 12:00:19 +01:00
|
|
|
pages. A page is almost always 4096 bytes except in unusual
|
|
|
|
kernel configurations with <quote>huge pages</quote>
|
2012-07-04 21:56:12 +02:00
|
|
|
(use <literal>getconf PAGE_SIZE</literal> to verify).
|
2010-03-13 12:00:19 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The shared memory size settings can be changed via the
|
2016-08-05 20:35:09 +02:00
|
|
|
<command>sysctl</command> interface. For example, to allow 16 GB:
|
2000-12-17 12:22:00 +01:00
|
|
|
<screen>
|
2010-03-13 12:00:19 +01:00
|
|
|
<prompt>$</prompt> <userinput>sysctl -w kernel.shmmax=17179869184</userinput>
|
|
|
|
<prompt>$</prompt> <userinput>sysctl -w kernel.shmall=4194304</userinput>
|
2000-12-17 12:22:00 +01:00
|
|
|
</screen>
|
2010-03-13 12:00:19 +01:00
|
|
|
In addition these settings can be preserved between reboots in
|
|
|
|
the file <filename>/etc/sysctl.conf</filename>. Doing that is
|
|
|
|
highly recommended.
|
2000-12-17 12:22:00 +01:00
|
|
|
</para>
|
|
|
|
|
2000-12-30 16:03:09 +01:00
|
|
|
<para>
|
2010-03-13 12:00:19 +01:00
|
|
|
Ancient distributions might not have the <command>sysctl</command> program,
|
2010-11-23 21:27:50 +01:00
|
|
|
but equivalent changes can be made by manipulating the
|
2005-11-05 00:14:02 +01:00
|
|
|
<filename>/proc</filename> file system:
|
2005-02-27 00:19:05 +01:00
|
|
|
<screen>
|
2010-03-13 12:00:19 +01:00
|
|
|
<prompt>$</prompt> <userinput>echo 17179869184 >/proc/sys/kernel/shmmax</userinput>
|
|
|
|
<prompt>$</prompt> <userinput>echo 4194304 >/proc/sys/kernel/shmall</userinput>
|
2005-02-27 00:19:05 +01:00
|
|
|
</screen>
|
2010-03-13 12:00:19 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The remaining defaults are quite generously sized, and usually
|
|
|
|
do not require changes.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
2002-11-06 00:16:56 +01:00
|
|
|
<varlistentry>
|
2014-09-09 19:56:29 +02:00
|
|
|
<term><systemitem class="osname">OS X</>
|
|
|
|
<indexterm><primary>OS X</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2002-11-06 00:16:56 +01:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2010-05-01 00:24:50 +02:00
|
|
|
The recommended method for configuring shared memory in OS X
|
|
|
|
is to create a file named <filename>/etc/sysctl.conf</>,
|
2007-02-01 01:28:19 +01:00
|
|
|
containing variable assignments such as:
|
2006-03-05 04:50:44 +01:00
|
|
|
<programlisting>
|
|
|
|
kern.sysv.shmmax=4194304
|
|
|
|
kern.sysv.shmmin=1
|
|
|
|
kern.sysv.shmmni=32
|
|
|
|
kern.sysv.shmseg=8
|
|
|
|
kern.sysv.shmall=1024
|
|
|
|
</programlisting>
|
2010-05-01 00:24:50 +02:00
|
|
|
Note that in some OS X versions,
|
2006-03-05 04:50:44 +01:00
|
|
|
<emphasis>all five</> shared-memory parameters must be set in
|
|
|
|
<filename>/etc/sysctl.conf</>, else the values will be ignored.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Beware that recent releases of OS X ignore attempts to set
|
|
|
|
<varname>SHMMAX</> to a value that isn't an exact multiple of 4096.
|
2002-11-06 00:16:56 +01:00
|
|
|
</para>
|
2005-10-16 23:22:12 +02:00
|
|
|
|
2006-03-02 21:30:21 +01:00
|
|
|
<para>
|
2016-08-05 20:35:09 +02:00
|
|
|
<varname>SHMALL</> is measured in 4 kB pages on this platform.
|
2006-03-02 21:30:21 +01:00
|
|
|
</para>
|
2005-10-16 23:22:12 +02:00
|
|
|
|
2004-12-27 00:06:56 +01:00
|
|
|
<para>
|
2010-05-01 00:24:50 +02:00
|
|
|
In older OS X versions, you will need to reboot to have changes in the
|
|
|
|
shared memory parameters take effect. As of 10.5 it is possible to
|
|
|
|
change all but <varname>SHMMNI</> on the fly, using
|
|
|
|
<application>sysctl</>. But it's still best to set up your preferred
|
|
|
|
values via <filename>/etc/sysctl.conf</>, so that the values will be
|
|
|
|
kept across reboots.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The file <filename>/etc/sysctl.conf</> is only honored in OS X
|
|
|
|
10.3.9 and later. If you are running a previous 10.3.x release,
|
|
|
|
you must edit the file <filename>/etc/rc</>
|
|
|
|
and change the values in the following commands:
|
|
|
|
<programlisting>
|
|
|
|
sysctl -w kern.sysv.shmmax
|
|
|
|
sysctl -w kern.sysv.shmmin
|
|
|
|
sysctl -w kern.sysv.shmmni
|
|
|
|
sysctl -w kern.sysv.shmseg
|
|
|
|
sysctl -w kern.sysv.shmall
|
|
|
|
</programlisting>
|
|
|
|
Note that
|
|
|
|
<filename>/etc/rc</> is usually overwritten by OS X system updates,
|
|
|
|
so you should expect to have to redo these edits after each update.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
In OS X 10.2 and earlier, instead edit these commands in the file
|
|
|
|
<filename>/System/Library/StartupItems/SystemTuning/SystemTuning</>.
|
2004-12-27 00:06:56 +01:00
|
|
|
</para>
|
2002-11-06 00:16:56 +01:00
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">SCO OpenServer</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>SCO OpenServer</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2016-08-05 20:35:09 +02:00
|
|
|
In the default configuration, only 512 kB of shared memory per
|
2005-08-30 17:48:28 +02:00
|
|
|
segment is allowed. To increase the setting, first change to the
|
|
|
|
directory <filename>/etc/conf/cf.d</>. To display the current value of
|
2007-02-01 01:28:19 +01:00
|
|
|
<varname>SHMMAX</>, run:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
./configure -y SHMMAX
|
|
|
|
</programlisting>
|
2007-02-01 01:28:19 +01:00
|
|
|
To set a new value for <varname>SHMMAX</>, run:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
./configure SHMMAX=<replaceable>value</>
|
|
|
|
</programlisting>
|
|
|
|
where <replaceable>value</> is the new value you want to use
|
2003-03-24 15:32:51 +01:00
|
|
|
(in bytes). After setting <varname>SHMMAX</>, rebuild the kernel:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
./link_unix
|
|
|
|
</programlisting>
|
|
|
|
and reboot.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2011-03-11 13:53:34 +01:00
|
|
|
<term><systemitem class="osname">Solaris</> 2.6 to 2.9 (Solaris
|
2014-05-07 03:28:58 +02:00
|
|
|
6 to Solaris 9)
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>Solaris</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2012-07-04 21:56:12 +02:00
|
|
|
The relevant settings can be changed in
|
2011-03-11 13:53:34 +01:00
|
|
|
<filename>/etc/system</>, for example:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
set shmsys:shminfo_shmmax=0x2000000
|
|
|
|
set shmsys:shminfo_shmmin=1
|
|
|
|
set shmsys:shminfo_shmmni=256
|
|
|
|
set shmsys:shminfo_shmseg=256
|
|
|
|
|
|
|
|
set semsys:seminfo_semmap=256
|
|
|
|
set semsys:seminfo_semmni=512
|
|
|
|
set semsys:seminfo_semmns=512
|
|
|
|
set semsys:seminfo_semmsl=32
|
|
|
|
</programlisting>
|
2011-03-11 13:53:34 +01:00
|
|
|
You need to reboot for the changes to take effect. See also
|
|
|
|
<ulink url="http://sunsite.uakom.sk/sunworldonline/swol-09-1997/swol-09-insidesolaris.html"></ulink>
|
|
|
|
for information on shared memory under older versions of Solaris.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term><systemitem class="osname">Solaris</> 2.10 (Solaris
|
2013-09-03 17:16:37 +02:00
|
|
|
10) and later</term>
|
2011-03-11 13:53:34 +01:00
|
|
|
<term><systemitem class="osname">OpenSolaris</></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2013-09-03 17:16:37 +02:00
|
|
|
In Solaris 10 and later, and OpenSolaris, the default shared memory and
|
2011-03-11 13:53:34 +01:00
|
|
|
semaphore settings are good enough for most
|
|
|
|
<productname>PostgreSQL</> applications. Solaris now defaults
|
2012-07-04 21:56:12 +02:00
|
|
|
to a <varname>SHMMAX</> of one-quarter of system <acronym>RAM</>.
|
|
|
|
To further adjust this setting, use a project setting associated
|
2011-03-11 13:53:34 +01:00
|
|
|
with the <literal>postgres</> user. For example, run the
|
|
|
|
following as <literal>root</>:
|
|
|
|
<programlisting>
|
|
|
|
projadd -c "PostgreSQL DB User" -K "project.max-shm-memory=(privileged,8GB,deny)" -U postgres -G postgres user.postgres
|
|
|
|
</programlisting>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
This command adds the <literal>user.postgres</> project and
|
2012-07-04 21:56:12 +02:00
|
|
|
sets the shared memory maximum for the <literal>postgres</>
|
2011-03-11 13:53:34 +01:00
|
|
|
user to 8GB, and takes effect the next time that user logs
|
|
|
|
in, or when you restart <productname>PostgreSQL</> (not reload).
|
|
|
|
The above assumes that <productname>PostgreSQL</> is run by
|
|
|
|
the <literal>postgres</> user in the <literal>postgres</>
|
|
|
|
group. No server reboot is required.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Other recommended kernel setting changes for database servers which will
|
|
|
|
have a large number of connections are:
|
|
|
|
<programlisting>
|
|
|
|
project.max-shm-ids=(priv,32768,deny)
|
|
|
|
project.max-sem-ids=(priv,4096,deny)
|
|
|
|
project.max-msg-ids=(priv,4096,deny)
|
|
|
|
</programlisting>
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2011-03-11 13:53:34 +01:00
|
|
|
Additionally, if you are running <productname>PostgreSQL</>
|
|
|
|
inside a zone, you may need to raise the zone resource usage
|
|
|
|
limits as well. See "Chapter2: Projects and Tasks" in the
|
2013-09-03 17:16:37 +02:00
|
|
|
<citetitle>System Administrator's Guide</> for more
|
2011-03-11 13:53:34 +01:00
|
|
|
information on <literal>projects</> and <command>prctl</>.
|
2000-07-22 16:49:01 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2014-05-07 03:28:58 +02:00
|
|
|
<term><systemitem class="osname">UnixWare</>
|
2003-08-31 19:32:24 +02:00
|
|
|
<indexterm><primary>UnixWare</><secondary>IPC configuration</></>
|
2014-05-07 03:28:58 +02:00
|
|
|
</term>
|
2000-07-22 16:49:01 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
On <productname>UnixWare</> 7, the maximum size for shared
|
2016-08-05 20:35:09 +02:00
|
|
|
memory segments is 512 kB in the default configuration.
|
2007-02-01 01:28:19 +01:00
|
|
|
To display the current value of <varname>SHMMAX</>, run:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
/etc/conf/bin/idtune -g SHMMAX
|
|
|
|
</programlisting>
|
|
|
|
which displays the current, default, minimum, and maximum
|
2003-03-24 15:32:51 +01:00
|
|
|
values. To set a new value for <varname>SHMMAX</>,
|
2007-02-01 01:28:19 +01:00
|
|
|
run:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
/etc/conf/bin/idtune SHMMAX <replaceable>value</>
|
|
|
|
</programlisting>
|
|
|
|
where <replaceable>value</> is the new value you want to use
|
|
|
|
(in bytes). After setting <varname>SHMMAX</>, rebuild the
|
2003-03-24 15:32:51 +01:00
|
|
|
kernel:
|
2000-07-22 16:49:01 +02:00
|
|
|
<programlisting>
|
|
|
|
/etc/conf/bin/idbuild -B
|
|
|
|
</programlisting>
|
|
|
|
and reboot.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
</variablelist>
|
2005-08-30 02:58:48 +02:00
|
|
|
|
2000-07-22 16:49:01 +02:00
|
|
|
</sect2>
|
|
|
|
|
2001-01-08 22:01:54 +01:00
|
|
|
<sect2>
|
|
|
|
<title>Resource Limits</title>
|
|
|
|
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
Unix-like operating systems enforce various kinds of resource limits
|
|
|
|
that might interfere with the operation of your
|
|
|
|
<productname>PostgreSQL</productname> server. Of particular
|
|
|
|
importance are limits on the number of processes per user, the
|
|
|
|
number of open files per process, and the amount of memory available
|
|
|
|
to each process. Each of these have a <quote>hard</quote> and a
|
|
|
|
<quote>soft</quote> limit. The soft limit is what actually counts
|
|
|
|
but it can be changed by the user up to the hard limit. The hard
|
|
|
|
limit can only be changed by the root user. The system call
|
|
|
|
<function>setrlimit</function> is responsible for setting these
|
|
|
|
parameters. The shell's built-in command <command>ulimit</command>
|
|
|
|
(Bourne shells) or <command>limit</command> (<application>csh</>) is
|
|
|
|
used to control the resource limits from the command line. On
|
|
|
|
BSD-derived systems the file <filename>/etc/login.conf</filename>
|
2003-03-24 15:32:51 +01:00
|
|
|
controls the various resource limits set during login. See the
|
|
|
|
operating system documentation for details. The relevant
|
2001-01-08 22:01:54 +01:00
|
|
|
parameters are <varname>maxproc</varname>,
|
2002-03-09 06:11:38 +01:00
|
|
|
<varname>openfiles</varname>, and <varname>datasize</varname>. For
|
|
|
|
example:
|
2001-01-08 22:01:54 +01:00
|
|
|
<programlisting>
|
|
|
|
default:\
|
|
|
|
...
|
|
|
|
:datasize-cur=256M:\
|
|
|
|
:maxproc-cur=256:\
|
|
|
|
:openfiles-cur=256:\
|
|
|
|
...
|
|
|
|
</programlisting>
|
|
|
|
(<literal>-cur</literal> is the soft limit. Append
|
|
|
|
<literal>-max</literal> to set the hard limit.)
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
Kernels can also have system-wide limits on some resources.
|
2001-02-09 21:38:15 +01:00
|
|
|
<itemizedlist>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2001-01-08 22:01:54 +01:00
|
|
|
On <productname>Linux</productname>
|
|
|
|
<filename>/proc/sys/fs/file-max</filename> determines the
|
2001-12-27 22:37:34 +01:00
|
|
|
maximum number of open files that the kernel will support. It can
|
2001-01-08 22:01:54 +01:00
|
|
|
be changed by writing a different number into the file or by
|
|
|
|
adding an assignment in <filename>/etc/sysctl.conf</filename>.
|
|
|
|
The maximum limit of files per process is fixed at the time the
|
|
|
|
kernel is compiled; see
|
|
|
|
<filename>/usr/src/linux/Documentation/proc.txt</filename> for
|
|
|
|
more information.
|
2001-02-09 21:38:15 +01:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</itemizedlist>
|
2001-01-08 22:01:54 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2001-11-21 07:09:45 +01:00
|
|
|
The <productname>PostgreSQL</productname> server uses one process
|
2001-01-08 22:01:54 +01:00
|
|
|
per connection so you should provide for at least as many processes
|
|
|
|
as allowed connections, in addition to what you need for the rest
|
|
|
|
of your system. This is usually not a problem but if you run
|
|
|
|
several servers on one machine things might get tight.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The factory default limit on open files is often set to
|
|
|
|
<quote>socially friendly</quote> values that allow many users to
|
|
|
|
coexist on a machine without using an inappropriate fraction of
|
|
|
|
the system resources. If you run many servers on a machine this
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
is perhaps what you want, but on dedicated servers you might want to
|
2001-01-08 22:01:54 +01:00
|
|
|
raise this limit.
|
|
|
|
</para>
|
2001-12-27 22:37:34 +01:00
|
|
|
|
|
|
|
<para>
|
|
|
|
On the other side of the coin, some systems allow individual
|
2002-03-09 06:11:38 +01:00
|
|
|
processes to open large numbers of files; if more than a few
|
|
|
|
processes do so then the system-wide limit can easily be exceeded.
|
2004-03-09 17:57:47 +01:00
|
|
|
If you find this happening, and you do not want to alter the
|
|
|
|
system-wide limit, you can set <productname>PostgreSQL</>'s <xref
|
|
|
|
linkend="guc-max-files-per-process"> configuration parameter to
|
2002-03-09 06:11:38 +01:00
|
|
|
limit the consumption of open files.
|
2001-12-27 22:37:34 +01:00
|
|
|
</para>
|
2001-01-08 22:01:54 +01:00
|
|
|
</sect2>
|
2000-07-22 16:49:01 +02:00
|
|
|
|
2010-03-21 01:43:40 +01:00
|
|
|
<sect2 id="linux-memory-overcommit">
|
2003-11-04 10:55:39 +01:00
|
|
|
<title>Linux Memory Overcommit</title>
|
|
|
|
|
2016-01-01 04:03:13 +01:00
|
|
|
<indexterm>
|
|
|
|
<primary>memory overcommit</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<indexterm>
|
|
|
|
<primary>OOM</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<indexterm>
|
|
|
|
<primary>overcommit</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
2003-11-04 10:55:39 +01:00
|
|
|
<para>
|
2003-11-16 18:01:50 +01:00
|
|
|
In Linux 2.4 and later, the default virtual memory behavior is not
|
2003-11-16 04:38:34 +01:00
|
|
|
optimal for <productname>PostgreSQL</productname>. Because of the
|
Update documentation on may/can/might:
Standard English uses "may", "can", and "might" in different ways:
may - permission, "You may borrow my rake."
can - ability, "I can lift that log."
might - possibility, "It might rain today."
Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice. Similarly, "It may crash" is better stated, "It might crash".
Also update two error messages mentioned in the documenation to match.
2007-01-31 21:56:20 +01:00
|
|
|
way that the kernel implements memory overcommit, the kernel might
|
2012-06-13 21:34:57 +02:00
|
|
|
terminate the <productname>PostgreSQL</productname> postmaster (the
|
2012-08-30 20:14:22 +02:00
|
|
|
master server process) if the memory demands of either
|
|
|
|
<productname>PostgreSQL</productname> or another process cause the
|
|
|
|
system to run out of virtual memory.
|
2003-11-04 10:55:39 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2003-11-16 04:38:34 +01:00
|
|
|
If this happens, you will see a kernel message that looks like
|
|
|
|
this (consult your system documentation and configuration on where
|
|
|
|
to look for such a message):
|
2003-11-04 10:55:39 +01:00
|
|
|
<programlisting>
|
2010-01-11 19:39:32 +01:00
|
|
|
Out of Memory: Killed process 12345 (postgres).
|
2003-11-04 10:55:39 +01:00
|
|
|
</programlisting>
|
2006-06-18 17:38:37 +02:00
|
|
|
This indicates that the <filename>postgres</filename> process
|
2003-11-16 18:01:50 +01:00
|
|
|
has been terminated due to memory pressure.
|
|
|
|
Although existing database connections will continue to function
|
|
|
|
normally, no new connections will be accepted. To recover,
|
2003-11-16 04:38:34 +01:00
|
|
|
<productname>PostgreSQL</productname> will need to be restarted.
|
2003-11-04 10:55:39 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2003-11-16 18:01:50 +01:00
|
|
|
One way to avoid this problem is to run
|
2007-03-06 10:54:23 +01:00
|
|
|
<productname>PostgreSQL</productname> on a machine where you can
|
|
|
|
be sure that other processes will not run the machine out of
|
|
|
|
memory. If memory is tight, increasing the swap space of the
|
2010-01-11 19:39:32 +01:00
|
|
|
operating system can help avoid the problem, because the
|
|
|
|
out-of-memory (OOM) killer is invoked only when physical memory and
|
2007-03-06 10:54:23 +01:00
|
|
|
swap space are exhausted.
|
2003-11-16 18:01:50 +01:00
|
|
|
</para>
|
|
|
|
|
2012-08-30 20:14:22 +02:00
|
|
|
<para>
|
|
|
|
If <productname>PostgreSQL</productname> itself is the cause of the
|
|
|
|
system running out of memory, you can avoid the problem by changing
|
|
|
|
your configuration. In some cases, it may help to lower memory-related
|
|
|
|
configuration parameters, particularly
|
|
|
|
<link linkend="guc-shared-buffers"><varname>shared_buffers</></link>
|
|
|
|
and <link linkend="guc-work-mem"><varname>work_mem</></link>. In
|
|
|
|
other cases, the problem may be caused by allowing too many connections
|
|
|
|
to the database server itself. In many cases, it may be better to reduce
|
|
|
|
<link linkend="guc-max-connections"><varname>max_connections</></link>
|
|
|
|
and instead make use of external connection-pooling software.
|
|
|
|
</para>
|
|
|
|
|
2003-11-16 18:01:50 +01:00
|
|
|
<para>
|
2010-01-11 19:39:32 +01:00
|
|
|
On Linux 2.6 and later, it is possible to modify the
|
2007-03-06 10:54:23 +01:00
|
|
|
kernel's behavior so that it will not <quote>overcommit</> memory.
|
2007-12-22 06:13:03 +01:00
|
|
|
Although this setting will not prevent the <ulink
|
|
|
|
url="http://lwn.net/Articles/104179/">OOM killer</> from being invoked
|
|
|
|
altogether, it will lower the chances significantly and will therefore
|
|
|
|
lead to more robust system behavior. This is done by selecting strict
|
|
|
|
overcommit mode via <command>sysctl</command>:
|
2003-11-04 10:55:39 +01:00
|
|
|
<programlisting>
|
|
|
|
sysctl -w vm.overcommit_memory=2
|
|
|
|
</programlisting>
|
2003-11-16 18:01:50 +01:00
|
|
|
or placing an equivalent entry in <filename>/etc/sysctl.conf</>.
|
2010-01-11 19:39:32 +01:00
|
|
|
You might also wish to modify the related setting
|
|
|
|
<varname>vm.overcommit_ratio</>. For details see the kernel documentation
|
2016-01-01 04:03:13 +01:00
|
|
|
file <ulink url="https://www.kernel.org/doc/Documentation/vm/overcommit-accounting"></ulink>.
|
2003-11-04 10:55:39 +01:00
|
|
|
</para>
|
|
|
|
|
2010-01-11 19:39:32 +01:00
|
|
|
<para>
|
|
|
|
Another approach, which can be used with or without altering
|
|
|
|
<varname>vm.overcommit_memory</>, is to set the process-specific
|
2014-06-19 02:12:47 +02:00
|
|
|
<firstterm>OOM score adjustment</> value for the postmaster process to
|
2012-06-13 21:34:57 +02:00
|
|
|
<literal>-1000</>, thereby guaranteeing it will not be targeted by the OOM
|
|
|
|
killer. The simplest way to do this is to execute
|
2010-01-11 19:39:32 +01:00
|
|
|
<programlisting>
|
2012-06-13 21:34:57 +02:00
|
|
|
echo -1000 > /proc/self/oom_score_adj
|
2010-01-11 19:39:32 +01:00
|
|
|
</programlisting>
|
|
|
|
in the postmaster's startup script just before invoking the postmaster.
|
|
|
|
Note that this action must be done as root, or it will have no effect;
|
|
|
|
so a root-owned startup script is the easiest place to do it. If you
|
2014-06-19 02:12:47 +02:00
|
|
|
do this, you should also set these environment variables in the startup
|
|
|
|
script before invoking the postmaster:
|
|
|
|
<programlisting>
|
|
|
|
export PG_OOM_ADJUST_FILE=/proc/self/oom_score_adj
|
|
|
|
export PG_OOM_ADJUST_VALUE=0
|
|
|
|
</programlisting>
|
|
|
|
These settings will cause postmaster child processes to run with the
|
|
|
|
normal OOM score adjustment of zero, so that the OOM killer can still
|
|
|
|
target them at need. You could use some other value for
|
|
|
|
<envar>PG_OOM_ADJUST_VALUE</> if you want the child processes to run
|
|
|
|
with some other OOM score adjustment. (<envar>PG_OOM_ADJUST_VALUE</>
|
|
|
|
can also be omitted, in which case it defaults to zero.) If you do not
|
|
|
|
set <envar>PG_OOM_ADJUST_FILE</>, the child processes will run with the
|
|
|
|
same OOM score adjustment as the postmaster, which is unwise since the
|
|
|
|
whole point is to ensure that the postmaster has a preferential setting.
|
2010-01-11 19:39:32 +01:00
|
|
|
</para>
|
|
|
|
|
2012-06-13 21:34:57 +02:00
|
|
|
<para>
|
|
|
|
Older Linux kernels do not offer <filename>/proc/self/oom_score_adj</>,
|
|
|
|
but may have a previous version of the same functionality called
|
|
|
|
<filename>/proc/self/oom_adj</>. This works the same except the disable
|
2014-06-19 02:12:47 +02:00
|
|
|
value is <literal>-17</> not <literal>-1000</>.
|
2012-06-13 21:34:57 +02:00
|
|
|
</para>
|
|
|
|
|
2010-01-11 19:39:32 +01:00
|
|
|
<note>
|
2003-11-04 10:55:39 +01:00
|
|
|
<para>
|
2003-11-16 18:01:50 +01:00
|
|
|
Some vendors' Linux 2.4 kernels are reported to have early versions
|
2004-12-13 19:05:10 +01:00
|
|
|
of the 2.6 overcommit <command>sysctl</command> parameter. However, setting
|
2003-11-16 18:01:50 +01:00
|
|
|
<literal>vm.overcommit_memory</> to 2
|
2010-02-03 18:25:06 +01:00
|
|
|
on a 2.4 kernel that does not have the relevant code will make
|
|
|
|
things worse, not better. It is recommended that you inspect
|
2003-11-16 18:01:50 +01:00
|
|
|
the actual kernel source code (see the function
|
|
|
|
<function>vm_enough_memory</> in the file <filename>mm/mmap.c</>)
|
2010-02-03 18:25:06 +01:00
|
|
|
to verify what is supported in your kernel before you try this in a 2.4
|
2003-11-16 18:01:50 +01:00
|
|
|
installation. The presence of the <filename>overcommit-accounting</>
|
|
|
|
documentation file should <emphasis>not</> be taken as evidence that the
|
|
|
|
feature is there. If in any doubt, consult a kernel expert or your
|
|
|
|
kernel vendor.
|
2003-11-04 10:55:39 +01:00
|
|
|
</para>
|
2010-01-11 19:39:32 +01:00
|
|
|
</note>
|
2003-11-04 10:55:39 +01:00
|
|
|
</sect2>
|
2014-03-03 19:52:48 +01:00
|
|
|
|
|
|
|
<sect2 id="linux-huge-pages">
|
|
|
|
<title>Linux huge pages</title>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Using huge pages reduces overhead when using large contiguous chunks of
|
|
|
|
memory, like <productname>PostgreSQL</productname> does. To enable this
|
|
|
|
feature in <productname>PostgreSQL</productname> you need a kernel
|
|
|
|
with <varname>CONFIG_HUGETLBFS=y</varname> and
|
|
|
|
<varname>CONFIG_HUGETLB_PAGE=y</varname>. You also have to tune the system
|
|
|
|
setting <varname>vm.nr_hugepages</varname>. To estimate the number of
|
|
|
|
necessary huge pages start <productname>PostgreSQL</productname> without
|
|
|
|
huge pages enabled and check the <varname>VmPeak</varname> value from the
|
2014-07-17 04:20:15 +02:00
|
|
|
proc file system:
|
2014-03-03 19:52:48 +01:00
|
|
|
<programlisting>
|
|
|
|
$ <userinput>head -1 /path/to/data/directory/postmaster.pid</userinput>
|
|
|
|
4170
|
|
|
|
$ <userinput>grep ^VmPeak /proc/4170/status</userinput>
|
|
|
|
VmPeak: 6490428 kB
|
|
|
|
</programlisting>
|
|
|
|
<literal>6490428</literal> / <literal>2048</literal>
|
|
|
|
(<varname>PAGE_SIZE</varname> is <literal>2MB</literal> in this case) are
|
|
|
|
roughly <literal>3169.154</literal> huge pages, so you will need at
|
|
|
|
least <literal>3170</literal> huge pages:
|
|
|
|
<programlisting>
|
|
|
|
$ <userinput>sysctl -w vm.nr_hugepages=3170</userinput>
|
|
|
|
</programlisting>
|
|
|
|
Sometimes the kernel is not able to allocate the desired number of huge
|
|
|
|
pages, so it might be necessary to repeat that command or to reboot. Don't
|
|
|
|
forget to add an entry to <filename>/etc/sysctl.conf</filename> to persist
|
|
|
|
this setting through reboots.
|
|
|
|
</para>
|
|
|
|
|
2014-10-13 23:23:36 +02:00
|
|
|
<para>
|
|
|
|
It is also necessary to give the database server operating system
|
|
|
|
user permission to use huge pages by setting
|
|
|
|
<varname>vm.hugetlb_shm_group</> via <application>sysctl</>, and
|
|
|
|
permission to lock memory with <command>ulimit -l</>.
|
|
|
|
</para>
|
|
|
|
|
2014-03-03 19:52:48 +01:00
|
|
|
<para>
|
|
|
|
The default behavior for huge pages in
|
|
|
|
<productname>PostgreSQL</productname> is to use them when possible and
|
|
|
|
to fallback to normal pages when failing. To enforce the use of huge
|
|
|
|
pages, you can set
|
|
|
|
<link linkend="guc-huge-pages"><varname>huge_pages</varname></link>
|
|
|
|
to <literal>on</literal>. Note that in this case
|
|
|
|
<productname>PostgreSQL</productname> will fail to start if not enough huge
|
|
|
|
pages are available.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
For a detailed description of the <productname>Linux</productname> huge
|
|
|
|
pages feature have a look
|
2016-01-01 04:26:57 +01:00
|
|
|
at <ulink url="https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt"></ulink>.
|
2014-03-03 19:52:48 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
</sect2>
|
2000-07-22 16:49:01 +02:00
|
|
|
</sect1>
|
|
|
|
|
|
|
|
|
2006-06-18 17:38:37 +02:00
|
|
|
<sect1 id="server-shutdown">
|
2002-11-11 21:14:04 +01:00
|
|
|
<title>Shutting Down the Server</title>
|
2000-06-18 23:24:54 +02:00
|
|
|
|
2006-06-18 17:38:37 +02:00
|
|
|
<indexterm zone="server-shutdown">
|
2003-08-31 19:32:24 +02:00
|
|
|
<primary>shutdown</>
|
|
|
|
</indexterm>
|
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
There are several ways to shut down the database server. You control
|
2006-06-18 17:38:37 +02:00
|
|
|
the type of shutdown by sending different signals to the master
|
|
|
|
<command>postgres</command> process.
|
2003-09-13 00:17:24 +02:00
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
<variablelist>
|
|
|
|
<varlistentry>
|
2003-08-31 19:32:24 +02:00
|
|
|
<term><systemitem>SIGTERM</systemitem><indexterm><primary>SIGTERM</></></term>
|
2000-06-18 23:24:54 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2008-04-27 00:47:40 +02:00
|
|
|
This is the <firstterm>Smart Shutdown</firstterm> mode.
|
2003-03-24 15:32:51 +01:00
|
|
|
After receiving <systemitem>SIGTERM</systemitem>, the server
|
|
|
|
disallows new connections, but lets existing sessions end their
|
2008-04-27 00:47:40 +02:00
|
|
|
work normally. It shuts down only after all of the sessions terminate.
|
|
|
|
If the server is in online backup mode, it additionally waits
|
|
|
|
until online backup mode is no longer active. While backup mode is
|
|
|
|
active, new connections will still be allowed, but only to superusers
|
|
|
|
(this exception allows a superuser to connect to terminate
|
2010-04-08 03:39:37 +02:00
|
|
|
online backup mode). If the server is in recovery when a smart
|
|
|
|
shutdown is requested, recovery and streaming replication will be
|
|
|
|
stopped only after all regular sessions have terminated.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
2003-08-31 19:32:24 +02:00
|
|
|
<term><systemitem>SIGINT</systemitem><indexterm><primary>SIGINT</></></term>
|
2000-06-18 23:24:54 +02:00
|
|
|
<listitem>
|
|
|
|
<para>
|
2008-04-27 00:47:40 +02:00
|
|
|
This is the <firstterm>Fast Shutdown</firstterm> mode.
|
2003-03-24 15:32:51 +01:00
|
|
|
The server disallows new connections and sends all existing
|
|
|
|
server processes <systemitem>SIGTERM</systemitem>, which will cause them
|
2002-03-09 06:11:38 +01:00
|
|
|
to abort their current transactions and exit promptly. It then
|
2010-02-03 18:25:06 +01:00
|
|
|
waits for all server processes to exit and finally shuts down.
|
2008-04-23 15:44:59 +02:00
|
|
|
If the server is in online backup mode, backup mode will be
|
2008-04-27 00:47:40 +02:00
|
|
|
terminated, rendering the backup useless.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
2003-08-31 19:32:24 +02:00
|
|
|
<term><systemitem>SIGQUIT</systemitem><indexterm><primary>SIGQUIT</></></term>
|
2000-06-18 23:24:54 +02:00
|
|
|
<listitem>
|
2003-03-24 15:32:51 +01:00
|
|
|
<para>
|
2008-04-27 00:47:40 +02:00
|
|
|
This is the <firstterm>Immediate Shutdown</firstterm> mode.
|
Send SIGKILL to children if they don't die quickly in immediate shutdown
On immediate shutdown, or during a restart-after-crash sequence,
postmaster used to send SIGQUIT (and then abandon ship if shutdown); but
this is not a good strategy if backends don't die because of that
signal. (This might happen, for example, if a backend gets tangled
trying to malloc() due to gettext(), as in an example illustrated by
MauMau.) This causes problems when later trying to restart the server,
because some processes are still attached to the shared memory segment.
Instead of just abandoning such backends to their fates, we now have
postmaster hang around for a little while longer, send a SIGKILL after
some reasonable waiting period, and then exit. This makes immediate
shutdown more reliable.
There is disagreement on whether it's best for postmaster to exit after
sending SIGKILL, or to stick around until all children have reported
death. If this controversy is resolved differently than what this patch
implements, it's an easy change to make.
Bug reported by MauMau in message 20DAEA8949EC4E2289C6E8E58560DEC0@maumau
MauMau and Álvaro Herrera
2013-06-28 23:20:53 +02:00
|
|
|
The server will send <systemitem>SIGQUIT</systemitem> to all child
|
2015-06-19 20:23:39 +02:00
|
|
|
processes and wait for them to terminate. If any do not terminate
|
|
|
|
within 5 seconds, they will be sent <systemitem>SIGKILL</systemitem>.
|
|
|
|
The master server process exits as soon as all child processes have
|
|
|
|
exited, without doing normal database shutdown processing.
|
|
|
|
This will lead to recovery (by
|
2002-03-09 06:11:38 +01:00
|
|
|
replaying the WAL log) upon next start-up. This is recommended
|
|
|
|
only in emergencies.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
2003-03-24 15:32:51 +01:00
|
|
|
</para>
|
2000-06-18 23:24:54 +02:00
|
|
|
|
2004-12-27 00:06:56 +01:00
|
|
|
<para>
|
|
|
|
The <xref linkend="app-pg-ctl"> program provides a convenient
|
|
|
|
interface for sending these signals to shut down the server.
|
2007-12-16 11:17:13 +01:00
|
|
|
Alternatively, you can send the signal directly using <command>kill</>
|
2007-12-17 15:00:52 +01:00
|
|
|
on non-Windows systems.
|
2006-06-18 17:38:37 +02:00
|
|
|
The <acronym>PID</> of the <command>postgres</command> process can be
|
2004-12-27 00:06:56 +01:00
|
|
|
found using the <command>ps</command> program, or from the file
|
|
|
|
<filename>postmaster.pid</filename> in the data directory. For
|
2000-06-18 23:24:54 +02:00
|
|
|
example, to do a fast shutdown:
|
|
|
|
<screen>
|
2001-11-28 21:49:10 +01:00
|
|
|
$ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput>
|
2000-06-18 23:24:54 +02:00
|
|
|
</screen>
|
|
|
|
</para>
|
2004-12-27 00:06:56 +01:00
|
|
|
|
2007-12-23 04:10:04 +01:00
|
|
|
<important>
|
|
|
|
<para>
|
|
|
|
It is best not to use <systemitem>SIGKILL</systemitem> to shut down
|
|
|
|
the server. Doing so will prevent the server from releasing
|
|
|
|
shared memory and semaphores, which might then have to be done
|
|
|
|
manually before a new server can be started. Furthermore,
|
|
|
|
<systemitem>SIGKILL</systemitem> kills the <command>postgres</command>
|
|
|
|
process without letting it relay the signal to its subprocesses,
|
|
|
|
so it will be necessary to kill the individual subprocesses by hand as
|
|
|
|
well.
|
|
|
|
</para>
|
|
|
|
</important>
|
2008-04-17 22:56:41 +02:00
|
|
|
|
|
|
|
<para>
|
2008-04-27 00:47:40 +02:00
|
|
|
To terminate an individual session while allowing other sessions to
|
|
|
|
continue, use <function>pg_terminate_backend()</> (see <xref
|
2008-04-17 22:56:41 +02:00
|
|
|
linkend="functions-admin-signal-table">) or send a
|
|
|
|
<systemitem>SIGTERM</> signal to the child process associated with
|
|
|
|
the session.
|
|
|
|
</para>
|
2000-06-18 23:24:54 +02:00
|
|
|
</sect1>
|
|
|
|
|
2011-01-31 18:32:03 +01:00
|
|
|
<sect1 id="upgrading">
|
|
|
|
<title>Upgrading a <productname>PostgreSQL</> Cluster</title>
|
|
|
|
|
|
|
|
<indexterm zone="upgrading">
|
|
|
|
<primary>upgrading</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<indexterm zone="upgrading">
|
|
|
|
<primary>version</primary>
|
|
|
|
<secondary>compatibility</secondary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
This section discusses how to upgrade your database data from one
|
|
|
|
<productname>PostgreSQL</> release to a newer one.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2016-08-15 19:49:49 +02:00
|
|
|
Current <productname>PostgreSQL</productname> version numbers consist of a
|
|
|
|
major and a minor version number. For example, in the version number 10.1,
|
|
|
|
the 10 is the major version number and the 1 is the minor version number,
|
|
|
|
meaning this would be the first minor release of the major release 10. For
|
|
|
|
releases before <productname>PostgreSQL</productname> version 10.0, version
|
|
|
|
numbers consist of three numbers, for example, 9.5.3. In those cases, the
|
|
|
|
major version consists of the first two digit groups of the version number,
|
|
|
|
e.g., 9.5, and the minor version is the third number, e.g., 3, meaning this
|
|
|
|
would be the third minor release of the major release 9.5.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Minor releases never change the internal storage format and are always
|
|
|
|
compatible with earlier and later minor releases of the same major version
|
|
|
|
number. For example, version 10.1 is compatible with version 10.0 and
|
|
|
|
version 10.6. Similarly, for example, 9.5.3 is compatible with 9.5.0,
|
|
|
|
9.5.1, and 9.5.6. To update between compatible versions, you simply
|
|
|
|
replace the executables while the server is down and restart the server.
|
|
|
|
The data directory remains unchanged — minor upgrades are that
|
|
|
|
simple.
|
2011-01-31 18:32:03 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
For <emphasis>major</> releases of <productname>PostgreSQL</>, the
|
|
|
|
internal data storage format is subject to change, thus complicating
|
|
|
|
upgrades. The traditional method for moving data to a new major version
|
2014-08-25 21:34:51 +02:00
|
|
|
is to dump and reload the database, though this can be slow. A
|
|
|
|
faster method is <xref linkend="pgupgrade">. Replication methods are
|
|
|
|
also available, as discussed below.
|
2011-01-31 18:32:03 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
New major versions also typically introduce some user-visible
|
|
|
|
incompatibilities, so application programming changes might be required.
|
|
|
|
All user-visible changes are listed in the release notes (<xref
|
|
|
|
linkend="release">); pay particular attention to the section
|
|
|
|
labeled "Migration". If you are upgrading across several major
|
|
|
|
versions, be sure to read the release notes for each intervening
|
|
|
|
version.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
Cautious users will want to test their client applications on the new
|
|
|
|
version before switching over fully; therefore, it's often a good idea to
|
|
|
|
set up concurrent installations of old and new versions. When
|
|
|
|
testing a <productname>PostgreSQL</> major upgrade, consider the
|
|
|
|
following categories of possible changes:
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<variablelist>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Administration</term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The capabilities available for administrators to monitor and control
|
|
|
|
the server often change and improve in each major release.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>SQL</term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
Typically this includes new SQL command capabilities and not changes
|
|
|
|
in behavior, unless specifically mentioned in the release notes.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Library API</term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
Typically libraries like <application>libpq</> only add new
|
|
|
|
functionality, again unless mentioned in the release notes.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>System Catalogs</term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
System catalog changes usually only affect database management tools.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Server C-language API</term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
This involves changes in the backend function API, which is written
|
|
|
|
in the C programming language. Such changes affect code that
|
|
|
|
references backend functions deep inside the server.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
</variablelist>
|
|
|
|
|
2014-08-25 21:34:51 +02:00
|
|
|
<sect2 id="upgrading-via-pgdumpall">
|
|
|
|
<title>Upgrading Data via <application>pg_dumpall</></title>
|
2011-01-31 18:32:03 +01:00
|
|
|
|
|
|
|
<para>
|
2014-08-25 21:34:51 +02:00
|
|
|
One upgrade method is to dump data from one major version of
|
|
|
|
<productname>PostgreSQL</> and reload it in another — to do
|
|
|
|
this, you must use a <emphasis>logical</> backup tool like
|
|
|
|
<application>pg_dumpall</>; file system
|
2011-01-31 18:32:03 +01:00
|
|
|
level backup methods will not work. (There are checks in place that prevent
|
|
|
|
you from using a data directory with an incompatible version of
|
|
|
|
<productname>PostgreSQL</productname>, so no great harm can be done by
|
|
|
|
trying to start the wrong server version on a data directory.)
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
It is recommended that you use the <application>pg_dump</> and
|
2014-08-25 21:34:51 +02:00
|
|
|
<application>pg_dumpall</> programs from the <emphasis>newer</>
|
|
|
|
version of
|
2011-01-31 18:32:03 +01:00
|
|
|
<productname>PostgreSQL</>, to take advantage of enhancements
|
|
|
|
that might have been made in these programs. Current releases of the
|
|
|
|
dump programs can read data from any server version back to 7.0.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
These instructions assume that your existing installation is under the
|
|
|
|
<filename>/usr/local/pgsql</> directory, and that the data area is in
|
|
|
|
<filename>/usr/local/pgsql/data</>. Substitute your paths
|
|
|
|
appropriately.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<procedure>
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
If making a backup, make sure that your database is not being updated.
|
|
|
|
This does not affect the integrity of the backup, but the changed
|
|
|
|
data would of course not be included. If necessary, edit the
|
|
|
|
permissions in the file <filename>/usr/local/pgsql/data/pg_hba.conf</>
|
|
|
|
(or equivalent) to disallow access from everyone except you.
|
|
|
|
See <xref linkend="client-authentication"> for additional information on
|
|
|
|
access control.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<indexterm>
|
|
|
|
<primary>pg_dumpall</primary>
|
|
|
|
<secondary>use during upgrade</secondary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
To back up your database installation, type:
|
|
|
|
<screen>
|
|
|
|
<userinput>pg_dumpall > <replaceable>outputfile</></userinput>
|
|
|
|
</screen>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
To make the backup, you can use the <application>pg_dumpall</application>
|
2014-08-25 21:34:51 +02:00
|
|
|
command from the version you are currently running; see <xref
|
|
|
|
linkend="backup-dump-all"> for more details. For best
|
2011-01-31 18:32:03 +01:00
|
|
|
results, however, try to use the <application>pg_dumpall</application>
|
|
|
|
command from <productname>PostgreSQL</productname> &version;,
|
|
|
|
since this version contains bug fixes and improvements over older
|
|
|
|
versions. While this advice might seem idiosyncratic since you
|
|
|
|
haven't installed the new version yet, it is advisable to follow
|
|
|
|
it if you plan to install the new version in parallel with the
|
|
|
|
old version. In that case you can complete the installation
|
|
|
|
normally and transfer the data later. This will also decrease
|
|
|
|
the downtime.
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Shut down the old server:
|
|
|
|
<screen>
|
|
|
|
<userinput>pg_ctl stop</>
|
|
|
|
</screen>
|
|
|
|
On systems that have <productname>PostgreSQL</> started at boot time,
|
|
|
|
there is probably a start-up file that will accomplish the same thing. For
|
|
|
|
example, on a <systemitem class="osname">Red Hat Linux</> system one
|
|
|
|
might find that this works:
|
|
|
|
<screen>
|
|
|
|
<userinput>/etc/rc.d/init.d/postgresql stop</userinput>
|
|
|
|
</screen>
|
|
|
|
See <xref linkend="runtime"> for details about starting and
|
2011-05-19 00:14:45 +02:00
|
|
|
stopping the server.
|
2011-01-31 20:58:49 +01:00
|
|
|
</para>
|
2011-01-31 18:32:03 +01:00
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
If restoring from backup, rename or delete the old installation
|
2014-08-25 21:34:51 +02:00
|
|
|
directory if it is not version-specific. It is a good idea to
|
|
|
|
rename the directory, rather than
|
2011-01-31 18:32:03 +01:00
|
|
|
delete it, in case you have trouble and need to revert to it. Keep
|
|
|
|
in mind the directory might consume significant disk space. To rename
|
|
|
|
the directory, use a command like this:
|
|
|
|
<screen>
|
|
|
|
<userinput>mv /usr/local/pgsql /usr/local/pgsql.old</>
|
|
|
|
</screen>
|
|
|
|
(Be sure to move the directory as a single unit so relative paths
|
|
|
|
remain unchanged.)
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Install the new version of <productname>PostgreSQL</productname> as
|
|
|
|
outlined in <![%standalone-include[the next section.]]>
|
|
|
|
<![%standalone-ignore[<xref linkend="install-procedure">.]]>
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Create a new database cluster if needed. Remember that you must
|
|
|
|
execute these commands while logged in to the special database user
|
|
|
|
account (which you already have if you are upgrading).
|
|
|
|
<programlisting>
|
|
|
|
<userinput>/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data</>
|
|
|
|
</programlisting>
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Restore your previous <filename>pg_hba.conf</> and any
|
|
|
|
<filename>postgresql.conf</> modifications.
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Start the database server, again using the special database user
|
|
|
|
account:
|
|
|
|
<programlisting>
|
|
|
|
<userinput>/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data</>
|
|
|
|
</programlisting>
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
|
|
|
|
<step>
|
|
|
|
<para>
|
|
|
|
Finally, restore your data from backup with:
|
|
|
|
<screen>
|
|
|
|
<userinput>/usr/local/pgsql/bin/psql -d postgres -f <replaceable>outputfile</></userinput>
|
|
|
|
</screen>
|
|
|
|
using the <emphasis>new</> <application>psql</>.
|
|
|
|
</para>
|
|
|
|
</step>
|
|
|
|
</procedure>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
The least downtime can be achieved by installing the new server in
|
|
|
|
a different directory and running both the old and the new servers
|
|
|
|
in parallel, on different ports. Then you can use something like:
|
|
|
|
|
|
|
|
<programlisting>
|
|
|
|
pg_dumpall -p 5432 | psql -d postgres -p 5433
|
|
|
|
</programlisting>
|
|
|
|
to transfer your data.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
</sect2>
|
|
|
|
|
2014-08-25 21:34:51 +02:00
|
|
|
<sect2 id="upgrading-via-pg-upgrade">
|
|
|
|
<title>Upgrading Data via <application>pg_upgrade</></title>
|
2011-01-31 18:32:03 +01:00
|
|
|
|
|
|
|
<para>
|
2014-08-25 21:34:51 +02:00
|
|
|
The <xref linkend="pgupgrade"> module allows an installation to
|
|
|
|
be migrated in-place from one major <productname>PostgreSQL</>
|
|
|
|
version to another. Upgrades can be performed in minutes,
|
|
|
|
particularly with <option>--link</> mode. It requires steps similar to
|
|
|
|
<application>pg_dumpall</> above, e.g. starting/stopping the server,
|
|
|
|
running <application>initdb</>. The <application>pg_upgrade</> <link
|
|
|
|
linkend="pgupgrade">documentation</> outlines the necessary steps.
|
2011-01-31 18:32:03 +01:00
|
|
|
</para>
|
|
|
|
|
2014-08-25 21:34:51 +02:00
|
|
|
</sect2>
|
|
|
|
|
|
|
|
<sect2 id="upgrading-via-replication">
|
|
|
|
<title>Upgrading Data via Replication</title>
|
|
|
|
|
2011-01-31 18:32:03 +01:00
|
|
|
<para>
|
|
|
|
It is also possible to use certain replication methods, such as
|
|
|
|
<productname>Slony</>, to create a standby server with the updated version of
|
2011-02-01 21:21:22 +01:00
|
|
|
<productname>PostgreSQL</>. This is possible because Slony supports
|
|
|
|
replication between different major versions of
|
2011-01-31 18:32:03 +01:00
|
|
|
<productname>PostgreSQL</>. The standby can be on the same computer or
|
|
|
|
a different computer. Once it has synced up with the master server
|
|
|
|
(running the older version of <productname>PostgreSQL</>), you can
|
|
|
|
switch masters and make the standby the master and shut down the older
|
|
|
|
database instance. Such a switch-over results in only several seconds
|
|
|
|
of downtime for an upgrade.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
</sect2>
|
|
|
|
</sect1>
|
|
|
|
|
2007-12-25 05:00:44 +01:00
|
|
|
<sect1 id="preventing-server-spoofing">
|
|
|
|
<title>Preventing Server Spoofing</title>
|
|
|
|
|
|
|
|
<indexterm zone="preventing-server-spoofing">
|
|
|
|
<primary>server spoofing</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
While the server is running, it is not possible for a malicious user
|
2009-04-24 22:46:16 +02:00
|
|
|
to take the place of the normal database server. However, when the
|
2010-02-03 18:25:06 +01:00
|
|
|
server is down, it is possible for a local user to spoof the normal
|
2007-12-25 05:00:44 +01:00
|
|
|
server by starting their own server. The spoof server could read
|
|
|
|
passwords and queries sent by clients, but could not return any data
|
|
|
|
because the <varname>PGDATA</> directory would still be secure because
|
|
|
|
of directory permissions. Spoofing is possible because any user can
|
|
|
|
start a database server; a client cannot identify an invalid server
|
|
|
|
unless it is specially configured.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2016-08-19 03:41:10 +02:00
|
|
|
On way to prevent spoofing of <literal>local</>
|
2007-12-25 05:00:44 +01:00
|
|
|
connections is to use a Unix domain socket directory (<xref
|
2012-08-10 23:26:44 +02:00
|
|
|
linkend="guc-unix-socket-directories">) that has write permission only
|
2007-12-25 05:00:44 +01:00
|
|
|
for a trusted local user. This prevents a malicious user from creating
|
2008-01-31 18:22:43 +01:00
|
|
|
their own socket file in that directory. If you are concerned that
|
2008-02-01 00:03:16 +01:00
|
|
|
some applications might still reference <filename>/tmp</> for the
|
|
|
|
socket file and hence be vulnerable to spoofing, during operating system
|
2010-05-27 01:49:19 +02:00
|
|
|
startup create a symbolic link <filename>/tmp/.s.PGSQL.5432</> that points
|
2008-02-01 00:03:16 +01:00
|
|
|
to the relocated socket file. You also might need to modify your
|
2010-05-27 01:49:19 +02:00
|
|
|
<filename>/tmp</> cleanup script to prevent removal of the symbolic link.
|
2008-01-31 18:22:43 +01:00
|
|
|
</para>
|
|
|
|
|
2016-08-19 03:41:10 +02:00
|
|
|
<para>
|
|
|
|
Another option for <literal>local</> connections is for clients to use
|
|
|
|
<link linkend="libpq-connect-requirepeer"><literal>requirepeer</></>
|
|
|
|
to specify the required owner of the server process connected to
|
|
|
|
the socket.
|
|
|
|
</para>
|
|
|
|
|
2008-01-31 18:22:43 +01:00
|
|
|
<para>
|
2010-05-27 01:49:19 +02:00
|
|
|
To prevent spoofing on TCP connections, the best solution is to use
|
|
|
|
SSL certificates and make sure that clients check the server's certificate.
|
|
|
|
To do that, the server
|
|
|
|
must be configured to accept only <literal>hostssl</> connections (<xref
|
2012-02-22 22:40:46 +01:00
|
|
|
linkend="auth-pg-hba-conf">) and have SSL key and certificate files
|
|
|
|
(<xref linkend="ssl-tcp">). The TCP client must connect using
|
2010-05-27 01:49:19 +02:00
|
|
|
<literal>sslmode=verify-ca</> or
|
|
|
|
<literal>verify-full</> and have the appropriate root certificate
|
2013-02-21 11:26:23 +01:00
|
|
|
file installed (<xref linkend="libq-ssl-certificates">).
|
2007-12-25 05:00:44 +01:00
|
|
|
</para>
|
|
|
|
</sect1>
|
2010-11-23 21:27:50 +01:00
|
|
|
|
2005-05-09 19:26:22 +02:00
|
|
|
<sect1 id="encryption-options">
|
|
|
|
<title>Encryption Options</title>
|
2005-05-09 19:13:04 +02:00
|
|
|
|
2005-05-09 19:26:22 +02:00
|
|
|
<indexterm zone="encryption-options">
|
2005-05-09 19:13:04 +02:00
|
|
|
<primary>encryption</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<productname>PostgreSQL</productname> offers encryption at several
|
|
|
|
levels, and provides flexibility in protecting data from disclosure
|
|
|
|
due to database server theft, unscrupulous administrators, and
|
2005-05-25 04:56:15 +02:00
|
|
|
insecure networks. Encryption might also be required to secure
|
|
|
|
sensitive data such as medical records or financial transactions.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
2010-11-23 21:27:50 +01:00
|
|
|
|
2005-05-09 19:13:04 +02:00
|
|
|
<variablelist>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Password Storage Encryption</term>
|
|
|
|
<listitem>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
By default, database user passwords are stored as MD5 hashes, so
|
2005-05-25 04:56:15 +02:00
|
|
|
the administrator cannot determine the actual password assigned
|
2005-05-09 19:13:04 +02:00
|
|
|
to the user. If MD5 encryption is used for client authentication,
|
|
|
|
the unencrypted password is never even temporarily present on the
|
2010-02-03 18:25:06 +01:00
|
|
|
server because the client MD5-encrypts it before being sent
|
2005-05-25 04:56:15 +02:00
|
|
|
across the network.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Encryption For Specific Columns</term>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2011-01-26 15:22:21 +01:00
|
|
|
The <xref linkend="pgcrypto"> module allows certain fields to be
|
|
|
|
stored encrypted.
|
2010-08-15 03:57:03 +02:00
|
|
|
This is useful if only some of the data is sensitive.
|
2005-05-09 19:13:04 +02:00
|
|
|
The client supplies the decryption key and the data is decrypted
|
|
|
|
on the server and then sent to the client.
|
|
|
|
</para>
|
2010-11-23 21:27:50 +01:00
|
|
|
|
2005-05-09 19:13:04 +02:00
|
|
|
<para>
|
|
|
|
The decrypted data and the decryption key are present on the
|
|
|
|
server for a brief time while it is being decrypted and
|
|
|
|
communicated between the client and server. This presents a brief
|
|
|
|
moment where the data and keys can be intercepted by someone with
|
|
|
|
complete access to the database server, such as the system
|
|
|
|
administrator.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Data Partition Encryption</term>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2013-12-06 15:47:39 +01:00
|
|
|
Storage encryption can be performed at the file system level or the
|
|
|
|
block level. Linux file system encryption options include eCryptfs
|
|
|
|
and EncFS, while FreeBSD uses PEFS. Block level or full disk
|
|
|
|
encryption options include dm-crypt + LUKS on Linux and GEOM
|
|
|
|
modules geli and gbde on FreeBSD. Many other operating systems
|
|
|
|
support this functionality, including Windows.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2005-11-05 00:14:02 +01:00
|
|
|
This mechanism prevents unencrypted data from being read from the
|
2005-05-25 04:56:15 +02:00
|
|
|
drives if the drives or the entire computer is stolen. This does
|
2005-11-05 00:14:02 +01:00
|
|
|
not protect against attacks while the file system is mounted,
|
2005-05-25 04:56:15 +02:00
|
|
|
because when mounted, the operating system provides an unencrypted
|
2005-11-05 00:14:02 +01:00
|
|
|
view of the data. However, to mount the file system, you need some
|
2005-05-25 04:56:15 +02:00
|
|
|
way for the encryption key to be passed to the operating system,
|
|
|
|
and sometimes the key is stored somewhere on the host that mounts
|
|
|
|
the disk.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Encrypting Passwords Across A Network</term>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The <literal>MD5</> authentication method double-encrypts the
|
|
|
|
password on the client before sending it to the server. It first
|
2010-02-03 18:25:06 +01:00
|
|
|
MD5-encrypts it based on the user name, and then encrypts it
|
2005-05-09 19:13:04 +02:00
|
|
|
based on a random salt sent by the server when the database
|
|
|
|
connection was made. It is this double-encrypted value that is
|
|
|
|
sent over the network to the server. Double-encryption not only
|
|
|
|
prevents the password from being discovered, it also prevents
|
2005-05-25 04:56:15 +02:00
|
|
|
another connection from using the same encrypted password to
|
|
|
|
connect to the database server at a later time.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Encrypting Data Across A Network</term>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
SSL connections encrypt all data sent across the network: the
|
|
|
|
password, the queries, and the data returned. The
|
|
|
|
<filename>pg_hba.conf</> file allows administrators to specify
|
|
|
|
which hosts can use non-encrypted connections (<literal>host</>)
|
|
|
|
and which require SSL-encrypted connections
|
|
|
|
(<literal>hostssl</>). Also, clients can specify that they
|
|
|
|
connect to servers only via SSL. <application>Stunnel</> or
|
|
|
|
<application>SSH</> can also be used to encrypt transmissions.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>SSL Host Authentication</term>
|
|
|
|
|
|
|
|
<listitem>
|
2010-05-27 01:49:19 +02:00
|
|
|
<para>
|
2008-11-13 10:45:25 +01:00
|
|
|
It is possible for both the client and server to provide SSL
|
|
|
|
certificates to each other. It takes some extra configuration
|
2005-05-09 19:13:04 +02:00
|
|
|
on each side, but this provides stronger verification of identity
|
2005-05-25 04:56:15 +02:00
|
|
|
than the mere use of passwords. It prevents a computer from
|
2005-05-09 19:13:04 +02:00
|
|
|
pretending to be the server just long enough to read the password
|
2010-05-27 01:49:19 +02:00
|
|
|
sent by the client. It also helps prevent <quote>man in the middle</>
|
2005-05-09 19:13:04 +02:00
|
|
|
attacks where a computer between the client and server pretends to
|
|
|
|
be the server and reads and passes all data between the client and
|
|
|
|
server.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term>Client-Side Encryption</term>
|
|
|
|
|
|
|
|
<listitem>
|
|
|
|
<para>
|
2010-05-27 01:49:19 +02:00
|
|
|
If the system administrator for the server's machine cannot be trusted,
|
|
|
|
it is necessary
|
2005-05-09 19:13:04 +02:00
|
|
|
for the client to encrypt the data; this way, unencrypted data
|
|
|
|
never appears on the database server. Data is encrypted on the
|
|
|
|
client before being sent to the server, and database results have
|
2005-05-25 04:56:15 +02:00
|
|
|
to be decrypted on the client before being used.
|
2005-05-09 19:13:04 +02:00
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
</variablelist>
|
|
|
|
|
|
|
|
</sect1>
|
|
|
|
|
2000-10-20 16:00:49 +02:00
|
|
|
<sect1 id="ssl-tcp">
|
2000-09-06 21:54:52 +02:00
|
|
|
<title>Secure TCP/IP Connections with SSL</title>
|
2000-08-29 06:15:43 +02:00
|
|
|
|
2001-05-13 00:51:36 +02:00
|
|
|
<indexterm zone="ssl-tcp">
|
|
|
|
<primary>SSL</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
2000-08-29 06:15:43 +02:00
|
|
|
<para>
|
2002-03-09 06:11:38 +01:00
|
|
|
<productname>PostgreSQL</> has native support for using
|
|
|
|
<acronym>SSL</> connections to encrypt client/server communications
|
2003-03-24 15:32:51 +01:00
|
|
|
for increased security. This requires that
|
|
|
|
<productname>OpenSSL</productname> is installed on both client and
|
|
|
|
server systems and that support in <productname>PostgreSQL</> is
|
|
|
|
enabled at build time (see <xref linkend="installation">).
|
2000-08-29 06:15:43 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2002-11-21 07:36:08 +01:00
|
|
|
With <acronym>SSL</> support compiled in, the
|
|
|
|
<productname>PostgreSQL</> server can be started with
|
2003-03-24 15:32:51 +01:00
|
|
|
<acronym>SSL</> enabled by setting the parameter
|
2004-12-27 00:06:56 +01:00
|
|
|
<xref linkend="guc-ssl"> to <literal>on</> in
|
2010-02-03 18:25:06 +01:00
|
|
|
<filename>postgresql.conf</>. The server will listen for both normal
|
2007-12-25 05:00:44 +01:00
|
|
|
and <acronym>SSL</> connections on the same TCP port, and will negotiate
|
|
|
|
with any connecting client on whether to use <acronym>SSL</>. By
|
|
|
|
default, this is at the client's option; see <xref
|
|
|
|
linkend="auth-pg-hba-conf"> about how to set up the server to require
|
|
|
|
use of <acronym>SSL</> for some or all connections.
|
2000-08-29 06:15:43 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2007-12-25 05:00:44 +01:00
|
|
|
<productname>PostgreSQL</productname> reads the system-wide
|
|
|
|
<productname>OpenSSL</productname> configuration file. By default, this
|
|
|
|
file is named <filename>openssl.cnf</filename> and is located in the
|
|
|
|
directory reported by <literal>openssl version -d</>.
|
|
|
|
This default can be overridden by setting environment variable
|
|
|
|
<envar>OPENSSL_CONF</envar> to the name of the desired configuration file.
|
2000-08-29 06:15:43 +02:00
|
|
|
</para>
|
|
|
|
|
2007-02-16 03:59:41 +01:00
|
|
|
<para>
|
|
|
|
<productname>OpenSSL</productname> supports a wide range of ciphers
|
2007-12-25 05:00:44 +01:00
|
|
|
and authentication algorithms, of varying strength. While a list of
|
|
|
|
ciphers can be specified in the <productname>OpenSSL</productname>
|
|
|
|
configuration file, you can specify ciphers specifically for use by
|
|
|
|
the database server by modifying <xref linkend="guc-ssl-ciphers"> in
|
2007-12-29 05:59:27 +01:00
|
|
|
<filename>postgresql.conf</>.
|
2007-02-16 03:59:41 +01:00
|
|
|
</para>
|
|
|
|
|
2007-12-29 05:27:02 +01:00
|
|
|
<note>
|
|
|
|
<para>
|
|
|
|
It is possible to have authentication without encryption overhead by
|
|
|
|
using <literal>NULL-SHA</> or <literal>NULL-MD5</> ciphers. However,
|
|
|
|
a man-in-the-middle could read and pass communications between client
|
|
|
|
and server. Also, encryption overhead is minimal compared to the
|
|
|
|
overhead of authentication. For these reasons NULL ciphers are not
|
|
|
|
recommended.
|
|
|
|
</para>
|
|
|
|
</note>
|
|
|
|
|
2007-02-16 03:59:41 +01:00
|
|
|
<para>
|
2012-02-22 22:40:46 +01:00
|
|
|
To start in <acronym>SSL</> mode, files containing the server certificate
|
|
|
|
and private key must exist. By default, these files are expected to be
|
|
|
|
named <filename>server.crt</> and <filename>server.key</>, respectively, in
|
|
|
|
the server's data directory, but other names and locations can be specified
|
|
|
|
using the configuration parameters <xref linkend="guc-ssl-cert-file">
|
|
|
|
and <xref linkend="guc-ssl-key-file">.
|
2016-03-19 11:03:22 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2008-03-31 04:43:14 +02:00
|
|
|
On Unix systems, the permissions on <filename>server.key</filename> must
|
|
|
|
disallow any access to world or group; achieve this by the command
|
2016-03-19 11:03:22 +01:00
|
|
|
<command>chmod 0600 server.key</command>. Alternatively, the file can be
|
|
|
|
owned by root and have group read access (that is, <literal>0640</literal>
|
|
|
|
permissions). That setup is intended for installations where certificate
|
|
|
|
and key files are managed by the operating system. The user under which
|
|
|
|
the <productname>PostgreSQL</productname> server runs should then be made a
|
|
|
|
member of the group that has access to those certificate and key files.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2008-03-31 04:43:14 +02:00
|
|
|
If the private key is protected with a passphrase, the
|
2007-12-25 05:00:44 +01:00
|
|
|
server will prompt for the passphrase and will not start until it has
|
|
|
|
been entered.
|
|
|
|
</para>
|
|
|
|
|
2010-05-27 01:49:19 +02:00
|
|
|
<para>
|
|
|
|
In some cases, the server certificate might be signed by an
|
|
|
|
<quote>intermediate</> certificate authority, rather than one that is
|
|
|
|
directly trusted by clients. To use such a certificate, append the
|
|
|
|
certificate of the signing authority to the <filename>server.crt</> file,
|
2013-12-06 15:42:08 +01:00
|
|
|
then its parent authority's certificate, and so on up to a certificate
|
|
|
|
authority, <quote>root</> or <quote>intermediate</>, that is trusted by
|
|
|
|
clients, i.e. signed by a certificate in the clients'
|
|
|
|
<filename>root.crt</filename> files.
|
2010-05-27 01:49:19 +02:00
|
|
|
</para>
|
|
|
|
|
2008-11-20 10:29:36 +01:00
|
|
|
<sect2 id="ssl-client-certificates">
|
2011-01-29 19:00:18 +01:00
|
|
|
<title>Using Client Certificates</title>
|
2010-05-27 01:49:19 +02:00
|
|
|
|
2016-07-16 20:12:44 +02:00
|
|
|
<para>
|
2007-12-25 05:00:44 +01:00
|
|
|
To require the client to supply a trusted certificate, place
|
2010-05-27 01:49:19 +02:00
|
|
|
certificates of the certificate authorities (<acronym>CA</acronym>s)
|
2007-12-25 05:00:44 +01:00
|
|
|
you trust in the file <filename>root.crt</filename> in the data
|
2012-02-22 22:40:46 +01:00
|
|
|
directory, set the parameter <xref linkend="guc-ssl-ca-file"> in
|
|
|
|
<filename>postgresql.conf</filename> to <literal>root.crt</literal>,
|
2016-07-16 20:12:44 +02:00
|
|
|
and add the authentication option <literal>clientcert=1</literal> to the
|
|
|
|
appropriate <literal>hostssl</> line(s) in <filename>pg_hba.conf</>.
|
2008-11-20 10:29:36 +01:00
|
|
|
A certificate will then be requested from the client during
|
2007-12-25 05:00:44 +01:00
|
|
|
SSL connection startup. (See <xref linkend="libpq-ssl"> for a
|
2008-11-20 10:29:36 +01:00
|
|
|
description of how to set up certificates on the client.) The server will
|
2007-12-25 05:00:44 +01:00
|
|
|
verify that the client's certificate is signed by one of the trusted
|
2016-07-16 20:12:44 +02:00
|
|
|
certificate authorities.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
If intermediate <acronym>CA</>s appear in
|
2013-12-06 15:42:08 +01:00
|
|
|
<filename>root.crt</filename>, the file must also contain certificate
|
|
|
|
chains to their root <acronym>CA</>s. Certificate Revocation List
|
|
|
|
(CRL) entries
|
2012-02-22 22:40:46 +01:00
|
|
|
are also checked if the parameter <xref linkend="guc-ssl-crl-file"> is set.
|
2008-02-01 00:31:33 +01:00
|
|
|
<!-- If this URL changes replace it with a URL to www.archive.org. -->
|
2008-01-08 19:07:38 +01:00
|
|
|
(See <ulink
|
2015-07-01 00:47:32 +02:00
|
|
|
url="http://h71000.www7.hp.com/doc/83final/ba554_90007/ch04s02.html"></>
|
2008-01-08 19:07:38 +01:00
|
|
|
for diagrams showing SSL certificate usage.)
|
2007-12-25 05:00:44 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2016-07-16 20:12:44 +02:00
|
|
|
The <literal>clientcert</literal> authentication option is available for
|
|
|
|
all authentication methods, but only in <filename>pg_hba.conf</> lines
|
|
|
|
specified as <literal>hostssl</>. When <literal>clientcert</literal> is
|
|
|
|
not specified or is set to 0, the server will still verify any presented
|
|
|
|
client certificates against its CA file, if one is configured — but
|
|
|
|
it will not insist that a client certificate be presented.
|
2010-05-27 01:49:19 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2013-12-06 15:42:08 +01:00
|
|
|
Note that the server's <filename>root.crt</filename> lists the top-level
|
|
|
|
CAs that are considered trusted for signing client certificates.
|
|
|
|
In principle it need
|
2010-05-27 01:49:19 +02:00
|
|
|
not list the CA that signed the server's certificate, though in most cases
|
|
|
|
that CA would also be trusted for client certificates.
|
2008-11-20 10:29:36 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2010-05-27 01:49:19 +02:00
|
|
|
If you are setting up client certificates, you may wish to use
|
|
|
|
the <literal>cert</> authentication method, so that the certificates
|
|
|
|
control user authentication as well as providing connection security.
|
2016-07-16 20:12:44 +02:00
|
|
|
See <xref linkend="auth-cert"> for details. (It is not necessary to
|
|
|
|
specify <literal>clientcert=1</literal> explicitly when using
|
|
|
|
the <literal>cert</> authentication method.)
|
2007-02-16 03:59:41 +01:00
|
|
|
</para>
|
2008-11-20 10:29:36 +01:00
|
|
|
</sect2>
|
2007-02-16 03:59:41 +01:00
|
|
|
|
2008-11-20 10:29:36 +01:00
|
|
|
<sect2 id="ssl-server-files">
|
|
|
|
<title>SSL Server File Usage</title>
|
2011-05-04 19:24:07 +02:00
|
|
|
|
|
|
|
<para>
|
|
|
|
<xref linkend="ssl-file-usage"> summarizes the files that are
|
2012-02-22 22:40:46 +01:00
|
|
|
relevant to the SSL setup on the server. (The shown file names are default
|
|
|
|
or typical names. The locally configured names could be different.)
|
2011-05-04 19:24:07 +02:00
|
|
|
</para>
|
2007-12-25 05:00:44 +01:00
|
|
|
|
2007-12-25 07:15:34 +01:00
|
|
|
<table id="ssl-file-usage">
|
|
|
|
<title>SSL Server File Usage</title>
|
|
|
|
<tgroup cols="3">
|
|
|
|
<thead>
|
|
|
|
<row>
|
|
|
|
<entry>File</entry>
|
|
|
|
<entry>Contents</entry>
|
|
|
|
<entry>Effect</entry>
|
|
|
|
</row>
|
|
|
|
</thead>
|
|
|
|
|
|
|
|
<tbody>
|
|
|
|
|
|
|
|
<row>
|
2012-02-22 22:40:46 +01:00
|
|
|
<entry><xref linkend="guc-ssl-cert-file"> (<filename>$PGDATA/server.crt</>)</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
<entry>server certificate</entry>
|
2010-05-27 01:49:19 +02:00
|
|
|
<entry>sent to client to indicate server's identity</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
2012-02-22 22:40:46 +01:00
|
|
|
<entry><xref linkend="guc-ssl-key-file"> (<filename>$PGDATA/server.key</>)</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
<entry>server private key</entry>
|
2010-05-27 01:49:19 +02:00
|
|
|
<entry>proves server certificate was sent by the owner; does not indicate
|
2007-12-25 18:06:52 +01:00
|
|
|
certificate owner is trustworthy</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
2012-02-22 22:40:46 +01:00
|
|
|
<entry><xref linkend="guc-ssl-ca-file"> (<filename>$PGDATA/root.crt</>)</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
<entry>trusted certificate authorities</entry>
|
2008-11-20 10:29:36 +01:00
|
|
|
<entry>checks that client certificate is
|
2007-12-25 07:15:34 +01:00
|
|
|
signed by a trusted certificate authority</entry>
|
|
|
|
</row>
|
|
|
|
|
|
|
|
<row>
|
2012-02-22 22:40:46 +01:00
|
|
|
<entry><xref linkend="guc-ssl-crl-file"> (<filename>$PGDATA/root.crl</>)</entry>
|
2007-12-25 07:15:34 +01:00
|
|
|
<entry>certificates revoked by certificate authorities</entry>
|
|
|
|
<entry>client certificate must not be on this list</entry>
|
|
|
|
</row>
|
|
|
|
|
|
|
|
</tbody>
|
|
|
|
</tgroup>
|
|
|
|
</table>
|
2011-05-04 19:24:07 +02:00
|
|
|
|
|
|
|
<para>
|
|
|
|
The files <filename>server.key</>, <filename>server.crt</>,
|
|
|
|
<filename>root.crt</filename>, and <filename>root.crl</filename>
|
2012-02-22 22:40:46 +01:00
|
|
|
(or their configured alternative names)
|
2011-05-04 19:24:07 +02:00
|
|
|
are only examined during server start; so you must restart
|
|
|
|
the server for changes in them to take effect.
|
|
|
|
</para>
|
2008-11-20 10:29:36 +01:00
|
|
|
</sect2>
|
2007-12-25 07:15:34 +01:00
|
|
|
|
|
|
|
<sect2 id="ssl-certificate-creation">
|
2011-02-01 23:00:26 +01:00
|
|
|
<title>Creating a Self-signed Certificate</title>
|
2007-12-25 05:00:44 +01:00
|
|
|
|
|
|
|
<para>
|
|
|
|
To create a quick self-signed certificate for the server, use the
|
|
|
|
following <productname>OpenSSL</productname> command:
|
2001-01-08 22:01:54 +01:00
|
|
|
<programlisting>
|
2002-09-27 04:04:39 +02:00
|
|
|
openssl req -new -text -out server.req
|
2001-01-08 22:01:54 +01:00
|
|
|
</programlisting>
|
2007-12-25 05:00:44 +01:00
|
|
|
Fill out the information that <application>openssl</> asks for. Make sure
|
|
|
|
you enter the local host name as <quote>Common Name</>; the challenge
|
|
|
|
password can be left blank. The program will generate a key that is
|
|
|
|
passphrase protected; it will not accept a passphrase that is less
|
|
|
|
than four characters long. To remove the passphrase (as you must if
|
|
|
|
you want automatic start-up of the server), run the commands:
|
2001-01-08 22:01:54 +01:00
|
|
|
<programlisting>
|
2002-09-27 04:04:39 +02:00
|
|
|
openssl rsa -in privkey.pem -out server.key
|
|
|
|
rm privkey.pem
|
2001-01-08 22:01:54 +01:00
|
|
|
</programlisting>
|
2007-12-25 05:00:44 +01:00
|
|
|
Enter the old passphrase to unlock the existing key. Now do:
|
2001-01-08 22:01:54 +01:00
|
|
|
<programlisting>
|
2002-09-27 04:04:39 +02:00
|
|
|
openssl req -x509 -in server.req -text -key server.key -out server.crt
|
2001-01-08 22:01:54 +01:00
|
|
|
</programlisting>
|
2007-12-25 05:00:44 +01:00
|
|
|
to turn the certificate into a self-signed certificate and to copy
|
|
|
|
the key and certificate to where the server will look for them.
|
2008-11-04 05:18:50 +01:00
|
|
|
Finally do:
|
2008-03-31 04:43:14 +02:00
|
|
|
<programlisting>
|
|
|
|
chmod og-rwx server.key
|
|
|
|
</programlisting>
|
|
|
|
because the server will reject the file if its permissions are more
|
|
|
|
liberal than this.
|
2007-12-25 05:00:44 +01:00
|
|
|
For more details on how to create your server private key and
|
|
|
|
certificate, refer to the <productname>OpenSSL</> documentation.
|
|
|
|
</para>
|
2004-09-23 15:16:02 +02:00
|
|
|
|
2007-12-25 05:00:44 +01:00
|
|
|
<para>
|
|
|
|
A self-signed certificate can be used for testing, but a certificate
|
|
|
|
signed by a certificate authority (<acronym>CA</>) (either one of the
|
|
|
|
global <acronym>CAs</> or a local one) should be used in production
|
2010-05-27 01:49:19 +02:00
|
|
|
so that clients can verify the server's identity. If all the clients
|
2008-11-13 10:45:25 +01:00
|
|
|
are local to the organization, using a local <acronym>CA</> is
|
|
|
|
recommended.
|
2007-12-25 05:00:44 +01:00
|
|
|
</para>
|
2004-09-23 15:16:02 +02:00
|
|
|
|
2007-12-25 05:00:44 +01:00
|
|
|
</sect2>
|
2004-09-27 00:51:49 +02:00
|
|
|
|
2000-08-29 06:15:43 +02:00
|
|
|
</sect1>
|
|
|
|
|
2000-10-20 16:00:49 +02:00
|
|
|
<sect1 id="ssh-tunnels">
|
2002-11-11 21:14:04 +01:00
|
|
|
<title>Secure TCP/IP Connections with <application>SSH</application> Tunnels</title>
|
2000-06-18 23:24:54 +02:00
|
|
|
|
2001-05-13 00:51:36 +02:00
|
|
|
<indexterm zone="ssh-tunnels">
|
|
|
|
<primary>ssh</primary>
|
|
|
|
</indexterm>
|
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
<para>
|
2010-02-03 18:25:06 +01:00
|
|
|
It is possible to use <application>SSH</application> to encrypt the network
|
2000-06-18 23:24:54 +02:00
|
|
|
connection between clients and a
|
2001-11-21 07:09:45 +01:00
|
|
|
<productname>PostgreSQL</productname> server. Done properly, this
|
2004-12-27 00:06:56 +01:00
|
|
|
provides an adequately secure network connection, even for non-SSL-capable
|
|
|
|
clients.
|
2000-06-18 23:24:54 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2002-11-11 21:14:04 +01:00
|
|
|
First make sure that an <application>SSH</application> server is
|
2003-03-24 15:32:51 +01:00
|
|
|
running properly on the same machine as the
|
|
|
|
<productname>PostgreSQL</productname> server and that you can log in using
|
2002-03-09 06:11:38 +01:00
|
|
|
<command>ssh</command> as some user. Then you can establish a secure
|
|
|
|
tunnel with a command like this from the client machine:
|
2000-06-18 23:24:54 +02:00
|
|
|
<programlisting>
|
2008-02-26 17:07:16 +01:00
|
|
|
ssh -L 63333:localhost:5432 joe@foo.com
|
2000-06-18 23:24:54 +02:00
|
|
|
</programlisting>
|
2008-02-26 17:07:16 +01:00
|
|
|
The first number in the <option>-L</option> argument, 63333, is the
|
2010-02-03 18:25:06 +01:00
|
|
|
port number of your end of the tunnel; it can be any unused port.
|
2008-02-26 17:07:16 +01:00
|
|
|
(IANA reserves ports 49152 through 65535 for private use.) The
|
2003-03-24 15:32:51 +01:00
|
|
|
second number, 5432, is the remote end of the tunnel: the port
|
2008-02-26 17:07:16 +01:00
|
|
|
number your server is using. The name or IP address between the
|
|
|
|
port numbers is the host with the database server you are going to
|
|
|
|
connect to, as seen from the host you are logging in to, which
|
|
|
|
is <literal>foo.com</literal> in this example. In order to connect
|
|
|
|
to the database server using this tunnel, you connect to port 63333
|
|
|
|
on the local machine:
|
2000-06-18 23:24:54 +02:00
|
|
|
<programlisting>
|
2008-02-26 17:07:16 +01:00
|
|
|
psql -h localhost -p 63333 postgres
|
2000-06-18 23:24:54 +02:00
|
|
|
</programlisting>
|
|
|
|
To the database server it will then look as though you are really
|
2008-02-26 17:07:16 +01:00
|
|
|
user <literal>joe</literal> on host <literal>foo.com</literal>
|
|
|
|
connecting to <literal>localhost</literal> in that context, and it
|
|
|
|
will use whatever authentication procedure was configured for
|
|
|
|
connections from this user and host. Note that the server will not
|
|
|
|
think the connection is SSL-encrypted, since in fact it is not
|
|
|
|
encrypted between the
|
2004-12-27 00:06:56 +01:00
|
|
|
<application>SSH</application> server and the
|
|
|
|
<productname>PostgreSQL</productname> server. This should not pose any
|
|
|
|
extra security risk as long as they are on the same machine.
|
|
|
|
</para>
|
2008-02-26 17:07:16 +01:00
|
|
|
|
2004-12-27 00:06:56 +01:00
|
|
|
<para>
|
|
|
|
In order for the
|
2002-03-09 06:11:38 +01:00
|
|
|
tunnel setup to succeed you must be allowed to connect via
|
2003-03-24 15:32:51 +01:00
|
|
|
<command>ssh</command> as <literal>joe@foo.com</literal>, just
|
2010-02-03 18:25:06 +01:00
|
|
|
as if you had attempted to use <command>ssh</command> to create a
|
2000-06-18 23:24:54 +02:00
|
|
|
terminal session.
|
|
|
|
</para>
|
|
|
|
|
2008-02-26 17:07:16 +01:00
|
|
|
<para>
|
|
|
|
You could also have set up the port forwarding as
|
|
|
|
<programlisting>
|
|
|
|
ssh -L 63333:foo.com:5432 joe@foo.com
|
|
|
|
</programlisting>
|
|
|
|
but then the database server will see the connection as coming in
|
|
|
|
on its <literal>foo.com</literal> interface, which is not opened by
|
|
|
|
the default setting <literal>listen_addresses =
|
|
|
|
'localhost'</literal>. This is usually not what you want.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
If you have to <quote>hop</quote> to the database server via some
|
|
|
|
login host, one possible setup could look like this:
|
|
|
|
<programlisting>
|
|
|
|
ssh -L 63333:db.foo.com:5432 joe@shell.foo.com
|
|
|
|
</programlisting>
|
2008-02-26 19:01:26 +01:00
|
|
|
Note that this way the connection
|
|
|
|
from <literal>shell.foo.com</literal>
|
|
|
|
to <literal>db.foo.com</literal> will not be encrypted by the SSH
|
|
|
|
tunnel.
|
2008-02-26 17:07:16 +01:00
|
|
|
SSH offers quite a few configuration possibilities when the network
|
|
|
|
is restricted in various ways. Please refer to the SSH
|
|
|
|
documentation for details.
|
|
|
|
</para>
|
|
|
|
|
2000-09-06 21:54:52 +02:00
|
|
|
<tip>
|
|
|
|
<para>
|
2002-11-11 21:14:04 +01:00
|
|
|
Several other applications exist that can provide secure tunnels using
|
2000-09-06 21:54:52 +02:00
|
|
|
a procedure similar in concept to the one just described.
|
|
|
|
</para>
|
|
|
|
</tip>
|
|
|
|
|
2000-06-18 23:24:54 +02:00
|
|
|
</sect1>
|
1998-09-30 07:41:54 +02:00
|
|
|
|
2011-10-25 20:02:55 +02:00
|
|
|
<sect1 id="event-log-registration">
|
|
|
|
<title>Registering <application>Event Log</> on <systemitem
|
|
|
|
class="osname">Windows</></title>
|
|
|
|
|
|
|
|
<indexterm zone="event-log-registration">
|
|
|
|
<primary>event log</primary>
|
|
|
|
<secondary>event log</secondary>
|
|
|
|
</indexterm>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
To register a <systemitem class="osname">Windows</>
|
|
|
|
<application>event log</> library with the operating system,
|
|
|
|
issue this command:
|
|
|
|
<screen>
|
|
|
|
<userinput>regsvr32 <replaceable>pgsql_library_directory</>/pgevent.dll</>
|
|
|
|
</screen>
|
|
|
|
This creates registry entries used by the event viewer, under the default
|
|
|
|
event source named <literal>PostgreSQL</literal>.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
To specify a different event source name (see
|
|
|
|
<xref linkend="guc-event-source">), use the <literal>/n</literal>
|
|
|
|
and <literal>/i</literal> options:
|
|
|
|
<screen>
|
|
|
|
<userinput>regsvr32 /n /i:<replaceable>event_source_name</> <replaceable>pgsql_library_directory</>/pgevent.dll</>
|
|
|
|
</screen>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
To unregister the <application>event log</> library from
|
|
|
|
the operating system, issue this command:
|
|
|
|
<screen>
|
|
|
|
<userinput>regsvr32 /u [/i:<replaceable>event_source_name</>] <replaceable>pgsql_library_directory</>/pgevent.dll</>
|
|
|
|
</screen>
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<note>
|
|
|
|
<para>
|
|
|
|
To enable event logging in the database server, modify
|
|
|
|
<xref linkend="guc-log-destination"> to include
|
|
|
|
<literal>eventlog</literal> in <filename>postgresql.conf</filename>.
|
|
|
|
</para>
|
|
|
|
</note>
|
|
|
|
</sect1>
|
|
|
|
|
2005-01-23 01:30:59 +01:00
|
|
|
</chapter>
|