<!-- doc/src/sgml/installation.sgml -->
<!--

The standalone version has some portions that are different from the version
that is integrated into the full documentation set, in particular as regards
links, so that INSTALL.html can be created without links to the main
documentation.  See standalone-profile.xsl for details.

-->

<chapter id="installation">
 <title>Installation from Source Code</title>

 <indexterm zone="installation">
  <primary>installation</primary>
 </indexterm>

 <!-- See also the version of this text in standalone-install.xml -->
 <para>
  This chapter describes the installation of
  <productname>PostgreSQL</productname> using the source code
  distribution.  If you are installing a pre-packaged distribution,
  such as an RPM or Debian package, ignore this chapter
  and see <xref linkend="install-binaries" /> instead.
 </para>

 <para>
  If you are building <productname>PostgreSQL</productname> for Microsoft
  Windows, read this chapter if you intend to build with MinGW or Cygwin;
  but if you intend to build with Microsoft's <productname>Visual
  C++</productname>, see <xref linkend="install-windows"/> instead.
 </para>

 <sect1 id="install-short">
  <title>Short Version</title>

  <para>
<synopsis>
./configure
make
su
make install
adduser postgres
mkdir /usr/local/pgsql/data
chown postgres /usr/local/pgsql/data
su - postgres
/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
/usr/local/pgsql/bin/pg_ctl -D /usr/local/pgsql/data -l logfile start
/usr/local/pgsql/bin/createdb test
/usr/local/pgsql/bin/psql test
</synopsis>
   The long version is the rest of this
   <phrase>chapter</phrase>.
  </para>
 </sect1>


 <sect1 id="install-requirements">
  <title>Requirements</title>

  <para>
   In general, a modern Unix-compatible platform should be able to run
   <productname>PostgreSQL</productname>.
   The platforms that had received specific testing at the
   time of release are described in <xref linkend="supported-platforms"/>
   below.
  </para>

  <para>
   The following software packages are required for building
   <productname>PostgreSQL</productname>:

   <itemizedlist>
    <listitem>
     <para>
      <indexterm>
       <primary>make</primary>
      </indexterm>

      <acronym>GNU</acronym> <application>make</application> version 3.80 or newer is required; other
      <application>make</application> programs or older <acronym>GNU</acronym> <application>make</application> versions will <emphasis>not</emphasis> work.
      (<acronym>GNU</acronym> <application>make</application> is sometimes installed under
      the name <filename>gmake</filename>.)  To test for <acronym>GNU</acronym>
      <application>make</application> enter:
<screen>
<userinput>make --version</userinput>
</screen>
     </para>
    </listitem>

    <listitem>
     <para>
      You need an <acronym>ISO</acronym>/<acronym>ANSI</acronym> C compiler (at least
      C99-compliant). Recent
      versions of <productname>GCC</productname> are recommended, but
      <productname>PostgreSQL</productname> is known to build using a wide variety
      of compilers from different vendors.
     </para>
    </listitem>

    <listitem>
     <para>
      <application>tar</application> is required to unpack the source
      distribution, in addition to either
      <application>gzip</application> or <application>bzip2</application>.
     </para>
    </listitem>

    <listitem>
     <para>
      <indexterm>
       <primary>readline</primary>
      </indexterm>
      <indexterm>
       <primary>libedit</primary>
      </indexterm>

      The <acronym>GNU</acronym> <productname>Readline</productname> library is used by
      default.  It allows <application>psql</application> (the
      PostgreSQL command line SQL interpreter) to remember each
      command you type, and allows you to use arrow keys to recall and
      edit previous commands.  This is very helpful and is strongly
      recommended.  If you don't want to use it then you must specify
      the <option>--without-readline</option> option to
      <filename>configure</filename>. As an alternative, you can often use the
      BSD-licensed <filename>libedit</filename> library, originally
      developed on <productname>NetBSD</productname>. The
      <filename>libedit</filename> library is
      GNU <productname>Readline</productname>-compatible and is used if
      <filename>libreadline</filename> is not found, or if
      <option>--with-libedit-preferred</option> is used as an
      option to <filename>configure</filename>. If you are using a package-based
      Linux distribution, be aware that you need both the
      <literal>readline</literal> and <literal>readline-devel</literal> packages, if
      those are separate in your distribution.
     </para>
    </listitem>

    <listitem>
     <para>
      <indexterm>
       <primary>zlib</primary>
      </indexterm>

      The <productname>zlib</productname> compression library is
      used by default. If you don't want to use it then you must
      specify the <option>--without-zlib</option> option to
      <filename>configure</filename>. Using this option disables
      support for compressed archives in <application>pg_dump</application> and
      <application>pg_restore</application>.
     </para>
    </listitem>
   </itemizedlist>
  </para>

  <para>
   The following packages are optional.  They are not required in the
   default configuration, but they are needed when certain build
   options are enabled, as explained below:

   <itemizedlist>
    <listitem>
     <para>
      To build the server programming language
      <application>PL/Perl</application> you need a full
      <productname>Perl</productname> installation, including the
      <filename>libperl</filename> library and the header files.
      The minimum required version is <productname>Perl</productname> 5.8.3.
      Since <application>PL/Perl</application> will be a shared
      library, the <indexterm><primary>libperl</primary></indexterm>
      <filename>libperl</filename> library must be a shared library
      also on most platforms.  This appears to be the default in
      recent <productname>Perl</productname> versions, but it was not
      in earlier versions, and in any case it is the choice of whomever
      installed Perl at your site.  <filename>configure</filename> will fail
      if building <application>PL/Perl</application> is selected but it cannot
      find a shared <filename>libperl</filename>.  In that case, you will have
      to rebuild and install <productname>Perl</productname> manually to be
      able to build <application>PL/Perl</application>.  During the
      configuration process for <productname>Perl</productname>, request a
      shared library.
     </para>

     <para>
      If you intend to make more than incidental use of
      <application>PL/Perl</application>, you should ensure that the
      <productname>Perl</productname> installation was built with the
      <literal>usemultiplicity</literal> option enabled (<literal>perl -V</literal>
      will show whether this is the case).
     </para>
    </listitem>

    <listitem>
     <para>
      To build the <application>PL/Python</application> server programming
      language, you need a <productname>Python</productname>
      installation with the header files and
      the <application>distutils</application> module.  The minimum
      required version is <productname>Python</productname> 2.6.
      <productname>Python 3</productname> is supported if it's
      version 3.1 or later; but see
      <xref linkend="plpython-python23"/>
      when using Python 3.
     </para>

     <para>
      Since <application>PL/Python</application> will be a shared
      library, the <indexterm><primary>libpython</primary></indexterm>
      <filename>libpython</filename> library must be a shared library
      also on most platforms.  This is not the case in a default
      <productname>Python</productname> installation built from source, but a
      shared library is available in many operating system
      distributions.  <filename>configure</filename> will fail if
      building <application>PL/Python</application> is selected but it cannot
      find a shared <filename>libpython</filename>.  That might mean that you
      either have to install additional packages or rebuild (part of) your
      <productname>Python</productname> installation to provide this shared
      library.  When building from source, run <productname>Python</productname>'s
      configure with the <literal>--enable-shared</literal> flag.
     </para>
    </listitem>

    <listitem>
     <para>
      To build the <application>PL/Tcl</application>
      procedural language, you of course need a <productname>Tcl</productname>
      installation.  The minimum required version is
      <productname>Tcl</productname> 8.4.
     </para>
    </listitem>

    <listitem>
     <para>
      To enable Native Language Support (<acronym>NLS</acronym>), that
      is, the ability to display a program's messages in a language
      other than English, you need an implementation of the
      <application>Gettext</application> <acronym>API</acronym>.  Some operating
      systems have this built-in (e.g., <systemitem
      class="osname">Linux</systemitem>, <systemitem class="osname">NetBSD</systemitem>,
      <systemitem class="osname">Solaris</systemitem>), for other systems you
      can download an add-on package from <ulink
      url="https://www.gnu.org/software/gettext/"></ulink>.
      If you are using the <application>Gettext</application> implementation in
      the <acronym>GNU</acronym> C library then you will additionally
      need the <productname>GNU Gettext</productname> package for some
      utility programs.  For any of the other implementations you will
      not need it.
     </para>
    </listitem>

    <listitem>
     <para>
      You need <productname>OpenSSL</productname>, if you want to support
      encrypted client connections.  <productname>OpenSSL</productname> is
      also required for random number generation on platforms that do not
      have <filename>/dev/urandom</filename> (except Windows).  The minimum
      version required is 1.0.1.
     </para>
    </listitem>

    <listitem>
     <para>
      You need <application>Kerberos</application>, <productname>OpenLDAP</productname>,
      and/or <application>PAM</application>, if you want to support authentication
      using those services.
     </para>
    </listitem>

    <listitem>
     <para>
      You need <productname>LZ4</productname>, if you want to support
      compression of data with this method; see
      <xref linkend="guc-default-toast-compression"/>.
     </para>
    </listitem>

    <listitem>
     <para>
      To build the <productname>PostgreSQL</productname> documentation,
      there is a separate set of requirements; see
      <xref linkend="docguide-toolsets"/>.
     </para>
    </listitem>
   </itemizedlist>
  </para>

  <para>
   If you are building from a <productname>Git</productname> tree instead of
   using a released source package, or if you want to do server development,
   you also need the following packages:

   <itemizedlist>
    <listitem>
     <para>
      <indexterm>
       <primary>flex</primary>
      </indexterm>
      <indexterm>
       <primary>lex</primary>
      </indexterm>
      <indexterm>
       <primary>bison</primary>
      </indexterm>
      <indexterm>
       <primary>yacc</primary>
      </indexterm>

      <application>Flex</application> and <application>Bison</application>
      are needed to build from a Git checkout, or if you changed the actual
      scanner and parser definition files. If you need them, be sure
      to get <application>Flex</application> 2.5.31 or later and
      <application>Bison</application> 1.875 or later. Other <application>lex</application>
      and <application>yacc</application> programs cannot be used.
     </para>
    </listitem>
    <listitem>
     <para>
      <indexterm>
       <primary>perl</primary>
      </indexterm>

      <application>Perl</application> 5.8.3 or later is needed to build from a Git checkout,
      or if you changed the input files for any of the build steps that
      use Perl scripts.  If building on Windows you will need
      <application>Perl</application> in any case.  <application>Perl</application> is
      also required to run some test suites.
     </para>
    </listitem>
   </itemizedlist>
  </para>

  <para>
   If you need to get a <acronym>GNU</acronym> package, you can find
   it at your local <acronym>GNU</acronym> mirror site (see <ulink
   url="https://www.gnu.org/prep/ftp"></ulink>
   for a list) or at <ulink
   url="ftp://ftp.gnu.org/gnu/"></ulink>.
  </para>

  <para>
   Also check that you have sufficient disk space. You will need about
   350 MB for the source tree during compilation and about 60 MB for
   the installation directory. An empty database cluster takes about
   40 MB; databases take about five times the amount of space that a
   flat text file with the same data would take. If you are going to
   run the regression tests you will temporarily need up to an extra
   300 MB. Use the <command>df</command> command to check free disk
   space.
  </para>
 </sect1>

 <sect1 id="install-getsource">
  <title>Getting the Source</title>

  <para>
   The <productname>PostgreSQL</productname> &version; sources can be obtained from the
   download section of our
   website: <ulink url="https://www.postgresql.org/download/"></ulink>.  You
   should get a file named <filename>postgresql-&version;.tar.gz</filename>
   or <filename>postgresql-&version;.tar.bz2</filename>. After
   you have obtained the file, unpack it:
<screen>
<userinput>gunzip postgresql-&version;.tar.gz</userinput>
<userinput>tar xf postgresql-&version;.tar</userinput>
</screen>
   (Use <command>bunzip2</command> instead of <command>gunzip</command> if
   you have the <filename>.bz2</filename> file.  Also, note that most
   modern versions of <command>tar</command> can unpack compressed archives
   directly, so you don't really need the
   separate <command>gunzip</command> or <command>bunzip2</command> step.)
   This will create a directory
   <filename>postgresql-&version;</filename> under the current directory
   with the <productname>PostgreSQL</productname> sources.
   Change into that directory for the rest
   of the installation procedure.
  </para>

  <para>
   You can also get the source directly from the version control repository, see
   <xref linkend="sourcerepo"/>.
  </para>
 </sect1>

 <sect1 id="install-procedure">
  <title>Installation Procedure</title>

  <procedure>

  <step id="configure">
   <title>Configuration</title>

   <indexterm zone="configure">
    <primary>configure</primary>
   </indexterm>

   <para>
    The first step of the installation procedure is to configure the
    source tree for your system and choose the options you would like.
    This is done by running the <filename>configure</filename> script. For a
    default installation simply enter:
<screen>
<userinput>./configure</userinput>
</screen>
    This script will run a number of tests to determine values for various
    system dependent variables and detect any quirks of your
    operating system, and finally will create several files in the
    build tree to record what it found.
   </para>

   <para>
    You can also run <filename>configure</filename> in a directory outside
    the source tree, and then build there, if you want to keep the build
    directory separate from the original source files.  This procedure is
    called a
    <indexterm><primary>VPATH</primary></indexterm><firstterm>VPATH</firstterm>
    build.  Here's how:
<screen>
<userinput>mkdir build_dir</userinput>
<userinput>cd build_dir</userinput>
<userinput>/path/to/source/tree/configure [options go here]</userinput>
<userinput>make</userinput>
</screen>
   </para>

   <para>
    The default configuration will build the server and utilities, as
    well as all client applications and interfaces that require only a
    C compiler. All files will be installed under
    <filename>/usr/local/pgsql</filename> by default.
   </para>

   <para>
    You can customize the build and installation process by supplying one
    or more command line options to <filename>configure</filename>.
    Typically you would customize the install location, or the set of
    optional features that are built.  <filename>configure</filename>
    has a large number of options, which are described in
    <xref linkend="configure-options"/>.
   </para>

   <para>
    Also, <filename>configure</filename> responds to certain environment
    variables, as described in <xref linkend="configure-envvars"/>.
    These provide additional ways to customize the configuration.
   </para>
  </step>

  <step id="build">
   <title>Build</title>

   <para>
    To start the build, type either of:
<screen>
<userinput>make</userinput>
<userinput>make all</userinput>
</screen>
    (Remember to use <acronym>GNU</acronym> <application>make</application>.)
    The build will take a few minutes depending on your
    hardware. The last line displayed should be:
<screen>
All of PostgreSQL successfully made. Ready to install.
</screen>
   </para>

  <para>
   If you want to build everything that can be built, including the
   documentation (HTML and man pages), and the additional modules
   (<filename>contrib</filename>), type instead:
<screen>
<userinput>make world</userinput>
</screen>
   The last line displayed should be:
<screen>
PostgreSQL, contrib, and documentation successfully made. Ready to install.
</screen>
   </para>

   <para>
    If you want to invoke the build from another makefile rather than
    manually, you must unset <varname>MAKELEVEL</varname> or set it to zero,
    for instance like this:
<programlisting>
build-postgresql:
        $(MAKE) -C postgresql MAKELEVEL=0 all
</programlisting>
    Failure to do that can lead to strange error messages, typically about
    missing header files.
   </para>
  </step>

  <step>
   <title>Regression Tests</title>

   <indexterm>
    <primary>regression test</primary>
   </indexterm>

   <para>
    If you want to test the newly built server before you install it,
    you can run the regression tests at this point. The regression
    tests are a test suite to verify that <productname>PostgreSQL</productname>
    runs on your machine in the way the developers expected it
    to. Type:
<screen>
<userinput>make check</userinput>
</screen>
    (This won't work as root; do it as an unprivileged user.)
    See <xref linkend="regress"/> for
    detailed information about interpreting the test results. You can
    repeat this test at any later time by issuing the same command.
   </para>
  </step>

  <step id="install">
   <title>Installing the Files</title>

   <note>
    <para>
     If you are upgrading an existing system be sure to read
     <xref linkend="upgrading"/>,
     which has instructions about upgrading a
     cluster.
    </para>
   </note>

   <para>
    To install <productname>PostgreSQL</productname> enter:
<screen>
<userinput>make install</userinput>
</screen>
    This will install files into the directories that were specified
    in <xref linkend="configure"/>. Make sure that you have appropriate
    permissions to write into that area. Normally you need to do this
    step as root. Alternatively, you can create the target
    directories in advance and arrange for appropriate permissions to
    be granted.
   </para>

   <para>
    To install the documentation (HTML and man pages), enter:
<screen>
<userinput>make install-docs</userinput>
</screen>
   </para>

   <para>
    If you built the world above, type instead:
<screen>
<userinput>make install-world</userinput>
</screen>
    This also installs the documentation.
   </para>

   <para>
    You can use <literal>make install-strip</literal> instead of
    <literal>make install</literal> to strip the executable files and
    libraries as they are installed.  This will save some space.  If
    you built with debugging support, stripping will effectively
    remove the debugging support, so it should only be done if
    debugging is no longer needed.  <literal>install-strip</literal>
    tries to do a reasonable job saving space, but it does not have
    perfect knowledge of how to strip every unneeded byte from an
    executable file, so if you want to save all the disk space you
    possibly can, you will have to do manual work.
   </para>

   <para>
    The standard installation provides all the header files needed for client
    application development as well as for server-side program
    development, such as custom functions or data types written in C.
   </para>

   <formalpara>
    <title>Client-only installation:</title>
    <para>
     If you want to install only the client applications and
     interface libraries, then you can use these commands:
<screen>
<userinput>make -C src/bin install</userinput>
<userinput>make -C src/include install</userinput>
<userinput>make -C src/interfaces install</userinput>
<userinput>make -C doc install</userinput>
</screen>
    <filename>src/bin</filename> has a few binaries for server-only use,
    but they are small.
    </para>
   </formalpara>
  </step>
  </procedure>

  <formalpara>
   <title>Uninstallation:</title>
   <para>
    To undo the installation use the command <command>make
    uninstall</command>. However, this will not remove any created directories.
   </para>
  </formalpara>

  <formalpara>
   <title>Cleaning:</title>

   <para>
    After the installation you can free disk space by removing the built
    files from the source tree with the command <command>make
    clean</command>. This will preserve the files made by the <command>configure</command>
    program, so that you can rebuild everything with <command>make</command>
    later on. To reset the source tree to the state in which it was
    distributed, use <command>make distclean</command>. If you are going to
    build for several platforms within the same source tree you must do
    this and re-configure for each platform.  (Alternatively, use
    a separate build tree for each platform, so that the source tree
    remains unmodified.)
   </para>
  </formalpara>

  <para>
   If you perform a build and then discover that your <command>configure</command>
   options were wrong, or if you change anything that <command>configure</command>
   investigates (for example, software upgrades), then it's a good
   idea to do <command>make distclean</command> before reconfiguring and
   rebuilding.  Without this, your changes in configuration choices
   might not propagate everywhere they need to.
  </para>

  <sect2 id="configure-options">
   <title><filename>configure</filename> Options</title>

   <indexterm zone="configure-options">
    <primary>configure options</primary>
   </indexterm>

   <para>
    <command>configure</command>'s command line options are explained below.
    This list is not exhaustive (use <literal>./configure --help</literal>
    to get one that is).  The options not covered here are meant for
    advanced use-cases such as cross-compilation, and are documented in
    the standard Autoconf documentation.
   </para>

   <sect3 id="configure-options-locations">
    <title>Installation Locations</title>

     <para>
      These options control where <literal>make install</literal> will put
      the files.  The <option>--prefix</option> option is sufficient for
      most cases.  If you have special needs, you can customize the
      installation subdirectories with the other options described in this
      section.  Beware however that changing the relative locations of the
      different subdirectories may render the installation non-relocatable,
      meaning you won't be able to move it after installation.
      (The <literal>man</literal> and <literal>doc</literal> locations are
      not affected by this restriction.)  For relocatable installs, you
      might want to use the <literal>--disable-rpath</literal> option
      described later.
     </para>

     <variablelist>
      <varlistentry>
       <term><option>--prefix=<replaceable>PREFIX</replaceable></option></term>
       <listitem>
        <para>
         Install all files under the directory <replaceable>PREFIX</replaceable>
         instead of <filename>/usr/local/pgsql</filename>. The actual
         files will be installed into various subdirectories; no files
         will ever be installed directly into the
         <replaceable>PREFIX</replaceable> directory.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--exec-prefix=<replaceable>EXEC-PREFIX</replaceable></option></term>
       <listitem>
        <para>
         You can install architecture-dependent files under a
         different prefix, <replaceable>EXEC-PREFIX</replaceable>, than what
         <replaceable>PREFIX</replaceable> was set to. This can be useful to
         share architecture-independent files between hosts. If you
         omit this, then <replaceable>EXEC-PREFIX</replaceable> is set equal to
         <replaceable>PREFIX</replaceable> and both architecture-dependent and
         independent files will be installed under the same tree,
         which is probably what you want.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--bindir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Specifies the directory for executable programs. The default
         is <filename><replaceable>EXEC-PREFIX</replaceable>/bin</filename>, which
         normally means <filename>/usr/local/pgsql/bin</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--sysconfdir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the directory for various configuration files,
         <filename><replaceable>PREFIX</replaceable>/etc</filename> by default.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--libdir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the location to install libraries and dynamically loadable
         modules. The default is
         <filename><replaceable>EXEC-PREFIX</replaceable>/lib</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--includedir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the directory for installing C and C++ header files. The
         default is <filename><replaceable>PREFIX</replaceable>/include</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--datarootdir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the root directory for various types of read-only data
         files.  This only sets the default for some of the following
         options.  The default is
         <filename><replaceable>PREFIX</replaceable>/share</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--datadir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the directory for read-only data files used by the
         installed programs. The default is
         <filename><replaceable>DATAROOTDIR</replaceable></filename>. Note that this has
         nothing to do with where your database files will be placed.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--localedir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the directory for installing locale data, in particular
         message translation catalog files.  The default is
         <filename><replaceable>DATAROOTDIR</replaceable>/locale</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--mandir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         The man pages that come with <productname>PostgreSQL</productname> will be installed under
         this directory, in their respective
         <filename>man<replaceable>x</replaceable></filename> subdirectories.
         The default is <filename><replaceable>DATAROOTDIR</replaceable>/man</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--docdir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Sets the root directory for installing documentation files,
         except <quote>man</quote> pages.  This only sets the default for
         the following options.  The default value for this option is
         <filename><replaceable>DATAROOTDIR</replaceable>/doc/postgresql</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--htmldir=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         The HTML-formatted documentation for
         <productname>PostgreSQL</productname> will be installed under
         this directory.  The default is
         <filename><replaceable>DATAROOTDIR</replaceable></filename>.
        </para>
       </listitem>
      </varlistentry>
     </variablelist>

     <note>
      <para>
       Care has been taken to make it possible to install
       <productname>PostgreSQL</productname> into shared installation locations
       (such as <filename>/usr/local/include</filename>) without
       interfering with the namespace of the rest of the system. First,
       the string <quote><literal>/postgresql</literal></quote> is
       automatically appended to <varname>datadir</varname>,
       <varname>sysconfdir</varname>, and <varname>docdir</varname>,
       unless the fully expanded directory name already contains the
       string <quote><literal>postgres</literal></quote> or
       <quote><literal>pgsql</literal></quote>. For example, if you choose
       <filename>/usr/local</filename> as prefix, the documentation will
       be installed in <filename>/usr/local/doc/postgresql</filename>,
       but if the prefix is <filename>/opt/postgres</filename>, then it
       will be in <filename>/opt/postgres/doc</filename>. The public C
       header files of the client interfaces are installed into
       <varname>includedir</varname> and are namespace-clean. The
       internal header files and the server header files are installed
       into private directories under <varname>includedir</varname>. See
       the documentation of each interface for information about how to
       access its header files. Finally, a private subdirectory will
       also be created, if appropriate, under <varname>libdir</varname>
       for dynamically loadable modules.
      </para>
     </note>

   </sect3>

   <sect3 id="configure-options-features">
    <title><productname>PostgreSQL</productname> Features</title>

    <para>
     The options described in this section enable building of
     various <productname>PostgreSQL</productname> features that are not
     built by default.  Most of these are non-default only because they
     require additional software, as described in
     <xref linkend="install-requirements"/>.
    </para>

     <variablelist>

      <varlistentry>
       <term><option>--enable-nls<optional>=<replaceable>LANGUAGES</replaceable></optional></option></term>
       <listitem>
        <para>
         Enables Native Language Support (<acronym>NLS</acronym>),
         that is, the ability to display a program's messages in a
         language other than English.
         <replaceable>LANGUAGES</replaceable> is an optional space-separated
         list of codes of the languages that you want supported, for
         example <literal>--enable-nls='de fr'</literal>.  (The intersection
         between your list and the set of actually provided
         translations will be computed automatically.)  If you do not
         specify a list, then all available translations are
         installed.
        </para>

        <para>
         To use this option, you will need an implementation of the
         <application>Gettext</application> API.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-perl</option></term>
       <listitem>
        <para>
         Build the <application>PL/Perl</application> server-side language.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-python</option></term>
       <listitem>
        <para>
         Build the <application>PL/Python</application> server-side language.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-tcl</option></term>
       <listitem>
        <para>
         Build the <application>PL/Tcl</application> server-side language.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-tclconfig=<replaceable>DIRECTORY</replaceable></option></term>
       <listitem>
        <para>
         Tcl installs the file <filename>tclConfig.sh</filename>, which
         contains configuration information needed to build modules
         interfacing to Tcl. This file is normally found automatically
         at a well-known location, but if you want to use a different
         version of Tcl you can specify the directory in which to look
         for <filename>tclConfig.sh</filename>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-icu</option></term>
       <listitem>
        <para>
         Build with support for
         the <productname>ICU</productname><indexterm><primary>ICU</primary></indexterm>
         library, enabling use of ICU collation
         features<phrase condition="standalone-ignore"> (see
         <xref linkend="collation"/>)</phrase>.
         This requires the <productname>ICU4C</productname> package
         to be installed.  The minimum required version
         of <productname>ICU4C</productname> is currently 4.2.
        </para>

        <para>
         By default,
         <productname>pkg-config</productname><indexterm><primary>pkg-config</primary></indexterm>
         will be used to find the required compilation options.  This is
         supported for <productname>ICU4C</productname> version 4.6 and later.
         For older versions, or if <productname>pkg-config</productname> is
         not available, the variables <envar>ICU_CFLAGS</envar>
         and <envar>ICU_LIBS</envar> can be specified
         to <filename>configure</filename>, like in this example:
<programlisting>
./configure ... --with-icu ICU_CFLAGS='-I/some/where/include' ICU_LIBS='-L/some/where/lib -licui18n -licuuc -licudata'
</programlisting>
         (If <productname>ICU4C</productname> is in the default search path
         for the compiler, then you still need to specify nonempty strings in
         order to avoid use of <productname>pkg-config</productname>, for
         example, <literal>ICU_CFLAGS=' '</literal>.)
        </para>
       </listitem>
      </varlistentry>

      <varlistentry id="configure-with-llvm">
       <term><option>--with-llvm</option></term>
       <listitem>
        <para>
         Build with support for <productname>LLVM</productname> based
         <acronym>JIT</acronym> compilation<phrase
         condition="standalone-ignore"> (see <xref
         linkend="jit"/>)</phrase>.  This
         requires the <productname>LLVM</productname> library to be installed.
         The minimum required version of <productname>LLVM</productname> is
         currently 3.9.
        </para>
        <para>
         <command>llvm-config</command><indexterm><primary>llvm-config</primary></indexterm>
         will be used to find the required compilation options.
         <command>llvm-config</command>, and then
         <command>llvm-config-$major-$minor</command> for all supported
         versions, will be searched for in your <envar>PATH</envar>.  If
         that would not yield the desired program,
         use <envar>LLVM_CONFIG</envar> to specify a path to the
         correct <command>llvm-config</command>. For example
<programlisting>
./configure ... --with-llvm LLVM_CONFIG='/path/to/llvm/bin/llvm-config'
</programlisting>
        </para>

        <para>
         <productname>LLVM</productname> support requires a compatible
         <command>clang</command> compiler (specified, if necessary, using the
         <envar>CLANG</envar> environment variable), and a working C++
         compiler (specified, if necessary, using the <envar>CXX</envar>
         environment variable).
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-lz4</option></term>
       <listitem>
        <para>
         Build with <productname>LZ4</productname> compression support.
         This allows the use of <productname>LZ4</productname> for
         compression of table data.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-ssl=<replaceable>LIBRARY</replaceable></option>
       <indexterm>
        <primary>OpenSSL</primary>
        <seealso>SSL</seealso>
       </indexterm>
       </term>
       <listitem>
        <para>
         Build with support for <acronym>SSL</acronym> (encrypted)
         connections. The only <replaceable>LIBRARY</replaceable>
         supported is <option>openssl</option>. This requires the
         <productname>OpenSSL</productname> package to be installed.
         <filename>configure</filename> will check for the required
         header files and libraries to make sure that your
         <productname>OpenSSL</productname> installation is sufficient
         before proceeding.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-openssl</option></term>
       <listitem>
        <para>
         Obsolete equivalent of <literal>--with-ssl=openssl</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-gssapi</option></term>
       <listitem>
        <para>
         Build with support for GSSAPI authentication. On many systems, the
         GSSAPI system (usually a part of the Kerberos installation) is not
         installed in a location
         that is searched by default (e.g., <filename>/usr/include</filename>,
         <filename>/usr/lib</filename>), so you must use the options
         <option>--with-includes</option> and <option>--with-libraries</option> in
         addition to this option.  <filename>configure</filename> will check
         for the required header files and libraries to make sure that
         your GSSAPI installation is sufficient before proceeding.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-ldap</option></term>
       <listitem>
        <para>
         Build with <acronym>LDAP</acronym><indexterm><primary>LDAP</primary></indexterm>
         support for authentication and connection parameter lookup (see
         <phrase id="install-ldap-links"><xref linkend="libpq-ldap"/> and
         <xref linkend="auth-ldap"/></phrase> for more information). On Unix,
         this requires the <productname>OpenLDAP</productname> package to be
         installed. On Windows, the default <productname>WinLDAP</productname>
         library is used.  <filename>configure</filename> will check for the required
         header files and libraries to make sure that your
         <productname>OpenLDAP</productname> installation is sufficient before
         proceeding.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-pam</option></term>
       <listitem>
        <para>
         Build with <acronym>PAM</acronym><indexterm><primary>PAM</primary></indexterm>
         (Pluggable Authentication Modules) support.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-bsd-auth</option></term>
       <listitem>
        <para>
         Build with BSD Authentication support.
         (The BSD Authentication framework is
         currently only available on OpenBSD.)
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-systemd</option></term>
       <listitem>
        <para>
         Build with support
         for <application>systemd</application><indexterm><primary>systemd</primary></indexterm>
         service notifications.  This improves integration if the server
         is started under <application>systemd</application> but has no impact
         otherwise<phrase condition="standalone-ignore">; see <xref linkend="server-start"/> for more
         information</phrase>.  <application>libsystemd</application> and the
         associated header files need to be installed to use this option.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-bonjour</option></term>
       <listitem>
        <para>
         Build with support for Bonjour automatic service discovery.
         This requires Bonjour support in your operating system.
         Recommended on macOS.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-uuid=<replaceable>LIBRARY</replaceable></option></term>
       <listitem>
        <para>
         Build the <xref linkend="uuid-ossp"/> module
         (which provides functions to generate UUIDs), using the specified
         UUID library.<indexterm><primary>UUID</primary></indexterm>
         <replaceable>LIBRARY</replaceable> must be one of:
        </para>
        <itemizedlist>
         <listitem>
          <para>
           <option>bsd</option> to use the UUID functions found in FreeBSD, NetBSD,
           and some other BSD-derived systems
          </para>
         </listitem>
         <listitem>
          <para>
           <option>e2fs</option> to use the UUID library created by
           the <literal>e2fsprogs</literal> project; this library is present in most
           Linux systems and in macOS, and can be obtained for other
           platforms as well
          </para>
         </listitem>
         <listitem>
          <para>
           <option>ossp</option> to use the <ulink
           url="http://www.ossp.org/pkg/lib/uuid/">OSSP UUID library</ulink>
          </para>
         </listitem>
        </itemizedlist>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-ossp-uuid</option></term>
       <listitem>
        <para>
         Obsolete equivalent of <literal>--with-uuid=ossp</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-libxml</option></term>
       <listitem>
        <para>
         Build with libxml2, enabling SQL/XML support.  Libxml2 version 2.6.23 or
         later is required for this feature.
        </para>

        <para>
         To detect the required compiler and linker options, PostgreSQL will
         query <command>pkg-config</command>, if that is installed and knows
         about libxml2.  Otherwise the program <command>xml2-config</command>,
         which is installed by libxml2, will be used if it is found.  Use
         of <command>pkg-config</command> is preferred, because it can deal
         with multi-architecture installations better.
        </para>

        <para>
         To use a libxml2 installation that is in an unusual location, you
         can set <command>pkg-config</command>-related environment
         variables (see its documentation), or set the environment variable
         <envar>XML2_CONFIG</envar> to point to
         the <command>xml2-config</command> program belonging to the libxml2
         installation, or set the variables <envar>XML2_CFLAGS</envar>
         and <envar>XML2_LIBS</envar>.  (If <command>pkg-config</command> is
         installed, then to override its idea of where libxml2 is you must
         either set <envar>XML2_CONFIG</envar> or set
         both <envar>XML2_CFLAGS</envar> and <envar>XML2_LIBS</envar> to
         nonempty strings.)
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-libxslt</option></term>
       <listitem>
        <para>
         Build with libxslt, enabling the
         <xref linkend="xml2"/>
         module to perform XSL transformations of XML.
         <option>--with-libxml</option> must be specified as well.
        </para>
       </listitem>
      </varlistentry>

     </variablelist>

   </sect3>

   <sect3 id="configure-options-anti-features">
    <title>Anti-Features</title>

    <para>
     The options described in this section allow disabling
     certain <productname>PostgreSQL</productname> features that are built
     by default, but which might need to be turned off if the required
     software or system features are not available.  Using these options is
     not recommended unless really necessary.
    </para>

     <variablelist>

      <varlistentry>
       <term><option>--without-readline</option></term>
       <listitem>
        <para>
         Prevents use of the <application>Readline</application> library
         (and <application>libedit</application> as well).  This option disables
         command-line editing and history in
         <application>psql</application>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-libedit-preferred</option></term>
       <listitem>
        <para>
         Favors the use of the BSD-licensed <application>libedit</application> library
         rather than GPL-licensed <application>Readline</application>.  This option
         is significant only if you have both libraries installed; the
         default in that case is to use <application>Readline</application>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--without-zlib</option></term>
       <listitem>
        <para>
         <indexterm>
          <primary>zlib</primary>
         </indexterm>
         Prevents use of the <application>Zlib</application> library.
         This disables
         support for compressed archives in <application>pg_dump</application>
         and <application>pg_restore</application>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--disable-spinlocks</option></term>
       <listitem>
        <para>
         Allow the build to succeed even if <productname>PostgreSQL</productname>
         has no CPU spinlock support for the platform.  The lack of
         spinlock support will result in very poor performance; therefore,
         this option should only be used if the build aborts and
         informs you that the platform lacks spinlock support. If this
         option is required to build <productname>PostgreSQL</productname> on
         your platform, please report the problem to the
         <productname>PostgreSQL</productname> developers.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--disable-atomics</option></term>
       <listitem>
        <para>
         Disable use of CPU atomic operations.  This option does nothing on
         platforms that lack such operations.  On platforms that do have
         them, this will result in poor performance.  This option is only
         useful for debugging or making performance comparisons.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--disable-thread-safety</option></term>
       <listitem>
        <para>
         Disable the thread-safety of client libraries.  This prevents
         concurrent threads in <application>libpq</application> and
         <application>ECPG</application> programs from safely controlling
         their private connection handles.  Use this only on platforms
         with deficient threading support.
        </para>
       </listitem>
      </varlistentry>

     </variablelist>

   </sect3>

   <sect3 id="configure-options-build-process">
    <title>Build Process Details</title>

     <variablelist>

      <varlistentry>
       <term><option>--with-includes=<replaceable>DIRECTORIES</replaceable></option></term>
       <listitem>
        <para>
         <replaceable>DIRECTORIES</replaceable> is a colon-separated list of
         directories that will be added to the list the compiler
         searches for header files. If you have optional packages
         (such as GNU <application>Readline</application>) installed in a non-standard
         location,
         you have to use this option and probably also the corresponding
         <option>--with-libraries</option> option.
        </para>
        <para>
         Example: <literal>--with-includes=/opt/gnu/include:/usr/sup/include</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-libraries=<replaceable>DIRECTORIES</replaceable></option></term>
       <listitem>
        <para>
         <replaceable>DIRECTORIES</replaceable> is a colon-separated list of
         directories to search for libraries. You will probably have
         to use this option (and the corresponding
         <option>--with-includes</option> option) if you have packages
         installed in non-standard locations.
        </para>
        <para>
         Example: <literal>--with-libraries=/opt/gnu/lib:/usr/sup/lib</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-system-tzdata=<replaceable>DIRECTORY</replaceable></option>
       <indexterm>
        <primary>time zone data</primary>
       </indexterm>
       </term>
       <listitem>
        <para>
         <productname>PostgreSQL</productname> includes its own time zone database,
         which it requires for date and time operations.  This time zone
         database is in fact compatible with the IANA time zone
         database provided by many operating systems such as FreeBSD,
         Linux, and Solaris, so it would be redundant to install it again.
         When this option is used, the system-supplied time zone database
         in <replaceable>DIRECTORY</replaceable> is used instead of the one
         included in the PostgreSQL source distribution.
         <replaceable>DIRECTORY</replaceable> must be specified as an
         absolute path.  <filename>/usr/share/zoneinfo</filename> is a
         likely directory on some operating systems.  Note that the
         installation routine will not detect mismatching or erroneous time
         zone data.  If you use this option, you are advised to run the
         regression tests to verify that the time zone data you have
         pointed to works correctly with <productname>PostgreSQL</productname>.
        </para>

        <indexterm><primary>cross compilation</primary></indexterm>

        <para>
         This option is mainly aimed at binary package distributors
         who know their target operating system well.  The main
         advantage of using this option is that the PostgreSQL package
         won't need to be upgraded whenever any of the many local
         daylight-saving time rules change.  Another advantage is that
         PostgreSQL can be cross-compiled more straightforwardly if the
         time zone database files do not need to be built during the
         installation.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-extra-version=<replaceable>STRING</replaceable></option></term>
       <listitem>
        <para>
         Append <replaceable>STRING</replaceable> to the PostgreSQL version number.  You
         can use this, for example, to mark binaries built from unreleased Git
         snapshots or containing custom patches with an extra version string,
         such as a <command>git describe</command> identifier or a
         distribution package release number.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--disable-rpath</option></term>
       <listitem>
        <para>
         Do not mark <productname>PostgreSQL</productname>'s executables
         to indicate that they should search for shared libraries in the
         installation's library directory (see <option>--libdir</option>).
         On most platforms, this marking uses an absolute path to the
         library directory, so that it will be unhelpful if you relocate
         the installation later.  However, you will then need to provide
         some other way for the executables to find the shared libraries.
         Typically this requires configuring the operating system's
         dynamic linker to search the library directory; see
         <xref linkend="install-post-shlibs"/> for more detail.
        </para>
       </listitem>
      </varlistentry>

     </variablelist>

   </sect3>

   <sect3 id="configure-options-misc">
    <title>Miscellaneous</title>

    <para>
     It's fairly common, particularly for test builds, to adjust the
     default port number with <option>--with-pgport</option>.
     The other options in this section are recommended only for advanced
     users.
    </para>

     <variablelist>

      <varlistentry>
       <term><option>--with-pgport=<replaceable>NUMBER</replaceable></option></term>
       <listitem>
        <para>
         Set <replaceable>NUMBER</replaceable> as the default port number for
         server and clients. The default is 5432. The port can always
         be changed later on, but if you specify it here then both
         server and clients will have the same default compiled in,
         which can be very convenient.  Usually the only good reason
         to select a non-default value is if you intend to run multiple
         <productname>PostgreSQL</productname> servers on the same machine.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-krb-srvnam=<replaceable>NAME</replaceable></option></term>
       <listitem>
        <para>
         The default name of the Kerberos service principal used
         by GSSAPI.
         <literal>postgres</literal> is the default. There's usually no
         reason to change this unless you are building for a Windows
         environment, in which case it must be set to upper case
         <literal>POSTGRES</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-segsize=<replaceable>SEGSIZE</replaceable></option></term>
       <listitem>
        <para>
         Set the <firstterm>segment size</firstterm>, in gigabytes.  Large tables are
         divided into multiple operating-system files, each of size equal
         to the segment size.  This avoids problems with file size limits
         that exist on many platforms.  The default segment size, 1 gigabyte,
         is safe on all supported platforms.  If your operating system has
         <quote>largefile</quote> support (which most do, nowadays), you can use
         a larger segment size.  This can be helpful to reduce the number of
         file descriptors consumed when working with very large tables.
         But be careful not to select a value larger than is supported
         by your platform and the file systems you intend to use.  Other
         tools you might wish to use, such as <application>tar</application>, could
         also set limits on the usable file size.
         It is recommended, though not absolutely required, that this value
         be a power of 2.
         Note that changing this value breaks on-disk database compatibility,
         meaning you cannot use <command>pg_upgrade</command> to upgrade to
         a build with a different segment size.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-blocksize=<replaceable>BLOCKSIZE</replaceable></option></term>
       <listitem>
        <para>
         Set the <firstterm>block size</firstterm>, in kilobytes.  This is the unit
         of storage and I/O within tables.  The default, 8 kilobytes,
         is suitable for most situations; but other values may be useful
         in special cases.
         The value must be a power of 2 between 1 and 32 (kilobytes).
         Note that changing this value breaks on-disk database compatibility,
         meaning you cannot use <command>pg_upgrade</command> to upgrade to
         a build with a different block size.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--with-wal-blocksize=<replaceable>BLOCKSIZE</replaceable></option></term>
       <listitem>
        <para>
         Set the <firstterm>WAL block size</firstterm>, in kilobytes.  This is the unit
         of storage and I/O within the WAL log.  The default, 8 kilobytes,
         is suitable for most situations; but other values may be useful
         in special cases.
         The value must be a power of 2 between 1 and 64 (kilobytes).
         Note that changing this value breaks on-disk database compatibility,
         meaning you cannot use <command>pg_upgrade</command> to upgrade to
         a build with a different WAL block size.
        </para>
       </listitem>
      </varlistentry>

     </variablelist>

   </sect3>

   <sect3 id="configure-options-devel">
    <title>Developer Options</title>

    <para>
     Most of the options in this section are only of interest for
     developing or debugging <productname>PostgreSQL</productname>.
     They are not recommended for production builds, except
     for <option>--enable-debug</option>, which can be useful to enable
     detailed bug reports in the unlucky event that you encounter a bug.
     On platforms supporting DTrace, <option>--enable-dtrace</option>
     may also be reasonable to use in production.
    </para>

    <para>
     When building an installation that will be used to develop code inside
     the server, it is recommended to use at least the
     options <option>--enable-debug</option>
     and <option>--enable-cassert</option>.
    </para>

     <variablelist>

      <varlistentry>
       <term><option>--enable-debug</option></term>
       <listitem>
        <para>
         Compiles all programs and libraries with debugging symbols.
         This means that you can run the programs in a debugger
         to analyze problems. This enlarges the size of the installed
         executables considerably, and on non-GCC compilers it usually
         also disables compiler optimization, causing slowdowns. However,
         having the symbols available is extremely helpful for dealing
         with any problems that might arise.  Currently, this option is
         recommended for production installations only if you use GCC.
         But you should always have it on if you are doing development work
         or running a beta version.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-cassert</option></term>
       <listitem>
        <para>
         Enables <firstterm>assertion</firstterm> checks in the server, which test for
         many <quote>cannot happen</quote> conditions.  This is invaluable for
         code development purposes, but the tests can slow down the
         server significantly.
         Also, having the tests turned on won't necessarily enhance the
         stability of your server!  The assertion checks are not categorized
         for severity, and so what might be a relatively harmless bug will
         still lead to server restarts if it triggers an assertion
         failure.  This option is not recommended for production use, but
         you should have it on for development work or when running a beta
         version.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-tap-tests</option></term>
       <listitem>
        <para>
         Enable tests using the Perl TAP tools.  This requires a Perl
         installation and the Perl module <literal>IPC::Run</literal>.
         <phrase condition="standalone-ignore">See <xref linkend="regress-tap"/> for more information.</phrase>
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-depend</option></term>
       <listitem>
        <para>
         Enables automatic dependency tracking.  With this option, the
         makefiles are set up so that all affected object files will
         be rebuilt when any header file is changed.  This is useful
         if you are doing development work, but is just wasted overhead
         if you intend only to compile once and install.  At present,
         this option only works with GCC.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-coverage</option></term>
       <listitem>
        <para>
         If using GCC, all programs and libraries are compiled with
         code coverage testing instrumentation.  When run, they
         generate files in the build directory with code coverage
         metrics.
         <phrase condition="standalone-ignore">See <xref linkend="regress-coverage"/>
         for more information.</phrase> This option is for use only with GCC
         and when doing development work.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-profiling</option></term>
       <listitem>
        <para>
         If using GCC, all programs and libraries are compiled so they
         can be profiled.  On backend exit, a subdirectory will be created
         that contains the <filename>gmon.out</filename> file containing
         profile data.
         This option is for use only with GCC and when doing development work.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><option>--enable-dtrace</option></term>
       <listitem>
        <para>
         <indexterm>
          <primary>DTrace</primary>
         </indexterm>
         Compiles <productname>PostgreSQL</productname> with support for the
         dynamic tracing tool DTrace.
         <phrase condition="standalone-ignore">See <xref linkend="dynamic-trace"/>
         for more information.</phrase>
        </para>

        <para>
         To point to the <command>dtrace</command> program, the
         environment variable <envar>DTRACE</envar> can be set.  This
         will often be necessary because <command>dtrace</command> is
         typically installed under <filename>/usr/sbin</filename>,
         which might not be in your <envar>PATH</envar>.
        </para>

        <para>
         Extra command-line options for the <command>dtrace</command> program
         can be specified in the environment variable
         <envar>DTRACEFLAGS</envar>.  On Solaris,
         to include DTrace support in a 64-bit binary, you must specify
         <literal>DTRACEFLAGS="-64"</literal>.  For example,
         using the GCC compiler:
<screen>
./configure CC='gcc -m64' --enable-dtrace DTRACEFLAGS='-64' ...
</screen>
         Using Sun's compiler:
<screen>
./configure CC='/opt/SUNWspro/bin/cc -xtarget=native64' --enable-dtrace DTRACEFLAGS='-64' ...
</screen>
        </para>
       </listitem>
      </varlistentry>
     </variablelist>

   </sect3>

  </sect2>

  <sect2 id="configure-envvars">
   <title><filename>configure</filename> Environment Variables</title>

   <indexterm zone="configure-envvars">
    <primary>configure environment variables</primary>
   </indexterm>

    <para>
     In addition to the ordinary command-line options described above,
     <filename>configure</filename> responds to a number of environment
     variables.
     You can specify environment variables on the
     <filename>configure</filename> command line, for example:
<screen>
<userinput>./configure CC=/opt/bin/gcc CFLAGS='-O2 -pipe'</userinput>
</screen>
     In this usage an environment variable is little different from a
     command-line option.
     You can also set such variables beforehand:
<screen>
<userinput>export CC=/opt/bin/gcc</userinput>
<userinput>export CFLAGS='-O2 -pipe'</userinput>
<userinput>./configure</userinput>
</screen>
     This usage can be convenient because many programs' configuration
     scripts respond to these variables in similar ways.
    </para>

    <para>
     The most commonly used of these environment variables are
     <envar>CC</envar> and <envar>CFLAGS</envar>.
     If you prefer a C compiler different from the one
     <filename>configure</filename> picks, you can set the
     variable <envar>CC</envar> to the program of your choice.
     By default, <filename>configure</filename> will pick
     <filename>gcc</filename> if available, else the platform's
     default (usually <filename>cc</filename>).  Similarly, you can override the
     default compiler flags if needed with the <envar>CFLAGS</envar> variable.
    </para>

    <para>
     Here is a list of the significant variables that can be set in
     this manner:

     <variablelist>
      <varlistentry>
       <term><envar>BISON</envar></term>
       <listitem>
        <para>
         Bison program
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CC</envar></term>
       <listitem>
        <para>
         C compiler
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CFLAGS</envar></term>
       <listitem>
        <para>
         options to pass to the C compiler
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CLANG</envar></term>
       <listitem>
        <para>
         path to <command>clang</command> program used to process source code
         for inlining when compiling with <literal>--with-llvm</literal>
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CPP</envar></term>
       <listitem>
        <para>
         C preprocessor
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CPPFLAGS</envar></term>
       <listitem>
        <para>
         options to pass to the C preprocessor
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CXX</envar></term>
       <listitem>
        <para>
         C++ compiler
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>CXXFLAGS</envar></term>
       <listitem>
        <para>
         options to pass to the C++ compiler
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>DTRACE</envar></term>
       <listitem>
        <para>
         location of the <command>dtrace</command> program
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>DTRACEFLAGS</envar></term>
       <listitem>
        <para>
         options to pass to the <command>dtrace</command> program
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>FLEX</envar></term>
       <listitem>
        <para>
         Flex program
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>LDFLAGS</envar></term>
       <listitem>
        <para>
         options to use when linking either executables or shared libraries
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>LDFLAGS_EX</envar></term>
       <listitem>
        <para>
         additional options for linking executables only
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>LDFLAGS_SL</envar></term>
       <listitem>
        <para>
         additional options for linking shared libraries only
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>LLVM_CONFIG</envar></term>
       <listitem>
        <para>
         <command>llvm-config</command> program used to locate the
         <productname>LLVM</productname> installation
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>MSGFMT</envar></term>
       <listitem>
        <para>
         <command>msgfmt</command> program for native language support
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>PERL</envar></term>
       <listitem>
        <para>
         Perl interpreter program.  This will be used to determine the
         dependencies for building PL/Perl.  The default is
         <command>perl</command>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>PYTHON</envar></term>
       <listitem>
        <para>
         Python interpreter program.  This will be used to
         determine the dependencies for building PL/Python.  Also,
         whether Python 2 or 3 is specified here (or otherwise
         implicitly chosen) determines which variant of the PL/Python
         language becomes available.  See
         <xref linkend="plpython-python23"/>
         for more information.  If this is not set, the following are probed
         in this order: <literal>python python3 python2</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>TCLSH</envar></term>
       <listitem>
        <para>
         Tcl interpreter program.  This will be used to
         determine the dependencies for building PL/Tcl.
         If this is not set, the following are probed in this
         order: <literal>tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85
         tclsh8.4 tclsh84</literal>.
        </para>
       </listitem>
      </varlistentry>

      <varlistentry>
       <term><envar>XML2_CONFIG</envar></term>
       <listitem>
        <para>
         <command>xml2-config</command> program used to locate the
         libxml2 installation
        </para>
       </listitem>
      </varlistentry>
     </variablelist>
    </para>

    <para>
     Sometimes it is useful to add compiler flags after-the-fact to the set
     that were chosen by <filename>configure</filename>.  An important example is
     that <application>gcc</application>'s <option>-Werror</option> option cannot be included
     in the <envar>CFLAGS</envar> passed to <filename>configure</filename>, because
     it will break many of <filename>configure</filename>'s built-in tests.  To add
     such flags, include them in the <envar>COPT</envar> environment variable
     while running <filename>make</filename>.  The contents of <envar>COPT</envar>
     are added to both the <envar>CFLAGS</envar> and <envar>LDFLAGS</envar>
     options set up by <filename>configure</filename>.  For example, you could do
<screen>
<userinput>make COPT='-Werror'</userinput>
</screen>
     or
<screen>
<userinput>export COPT='-Werror'</userinput>
<userinput>make</userinput>
</screen>
    </para>

    <note>
     <para>
      If using GCC, it is best to build with an optimization level of
      at least <option>-O1</option>, because using no optimization
      (<option>-O0</option>) disables some important compiler warnings (such
      as the use of uninitialized variables).  However, non-zero
      optimization levels can complicate debugging because stepping
      through compiled code will usually not match up one-to-one with
      source code lines.  If you get confused while trying to debug
      optimized code, recompile the specific files of interest with
      <option>-O0</option>.  An easy way to do this is by passing an option
      to <application>make</application>: <command>make PROFILE=-O0 file.o</command>.
     </para>

     <para>
      The <envar>COPT</envar> and <envar>PROFILE</envar> environment variables are
      actually handled identically by the <productname>PostgreSQL</productname>
      makefiles.  Which to use is a matter of preference, but a common habit
      among developers is to use <envar>PROFILE</envar> for one-time flag
      adjustments, while <envar>COPT</envar> might be kept set all the time.
     </para>
    </note>
  </sect2>
 </sect1>

 <sect1 id="install-post">
  <title>Post-Installation Setup</title>

  <sect2 id="install-post-shlibs">
   <title>Shared Libraries</title>

   <indexterm>
    <primary>shared library</primary>
   </indexterm>

   <para>
    On some systems with shared libraries
    you need to tell the system how to find the newly installed
    shared libraries.  The systems on which this is
    <emphasis>not</emphasis> necessary include
    <systemitem class="osname">FreeBSD</systemitem>,
    <systemitem class="osname">HP-UX</systemitem>,
    <systemitem class="osname">Linux</systemitem>,
    <systemitem class="osname">NetBSD</systemitem>, <systemitem
    class="osname">OpenBSD</systemitem>, and
    <systemitem class="osname">Solaris</systemitem>.
   </para>

   <para>
    The method to set the shared library search path varies between
    platforms, but the most widely-used method is to set the
    environment variable <envar>LD_LIBRARY_PATH</envar> like so: In Bourne
    shells (<command>sh</command>, <command>ksh</command>, <command>bash</command>, <command>zsh</command>):
<programlisting>
LD_LIBRARY_PATH=/usr/local/pgsql/lib
export LD_LIBRARY_PATH
</programlisting>
    or in <command>csh</command> or <command>tcsh</command>:
<programlisting>
setenv LD_LIBRARY_PATH /usr/local/pgsql/lib
</programlisting>
    Replace <literal>/usr/local/pgsql/lib</literal> with whatever you set
    <option><literal>--libdir</literal></option> to in <xref linkend="configure"/>.
    You should put these commands into a shell start-up file such as
    <filename>/etc/profile</filename> or <filename>~/.bash_profile</filename>.  Some
    good information about the caveats associated with this method can
    be found at <ulink
    url="http://xahlee.info/UnixResource_dir/_/ldpath.html"></ulink>.
   </para>

   <para>
    On some systems it might be preferable to set the environment
    variable <envar>LD_RUN_PATH</envar> <emphasis>before</emphasis>
    building.
   </para>

   <para>
    On <systemitem class="osname">Cygwin</systemitem>, put the library
    directory in the <envar>PATH</envar> or move the
    <filename>.dll</filename> files into the <filename>bin</filename>
    directory.
   </para>

   <para>
    If in doubt, refer to the manual pages of your system (perhaps
    <command>ld.so</command> or <command>rld</command>). If you later
    get a message like:
<screen>
psql: error in loading shared libraries
libpq.so.2.1: cannot open shared object file: No such file or directory
</screen>
    then this step was necessary.  Simply take care of it then.
   </para>

   <para>
    <indexterm>
     <primary>ldconfig</primary>
    </indexterm>
    If you are on <systemitem class="osname">Linux</systemitem> and you have root
    access, you can run:
<programlisting>
/sbin/ldconfig /usr/local/pgsql/lib
</programlisting>
    (or equivalent directory) after installation to enable the
    run-time linker to find the shared libraries faster.  Refer to the
    manual page of <command>ldconfig</command> for more information.  On
    <systemitem class="osname">FreeBSD</systemitem>, <systemitem
    class="osname">NetBSD</systemitem>, and <systemitem
    class="osname">OpenBSD</systemitem> the command is:
<programlisting>
/sbin/ldconfig -m /usr/local/pgsql/lib
</programlisting>
    instead.  Other systems are not known to have an equivalent
    command.
   </para>
  </sect2>

  <sect2>
   <title>Environment Variables</title>

   <indexterm>
    <primary><envar>PATH</envar></primary>
   </indexterm>

   <para>
    If you installed into <filename>/usr/local/pgsql</filename> or some other
    location that is not searched for programs by default, you should
    add <filename>/usr/local/pgsql/bin</filename> (or whatever you set
    <option><literal>--bindir</literal></option> to in <xref linkend="configure"/>)
    into your <envar>PATH</envar>.  Strictly speaking, this is not
    necessary, but it will make the use of <productname>PostgreSQL</productname>
    much more convenient.
   </para>

   <para>
    To do this, add the following to your shell start-up file, such as
    <filename>~/.bash_profile</filename> (or <filename>/etc/profile</filename>, if you
    want it to affect all users):
<programlisting>
PATH=/usr/local/pgsql/bin:$PATH
export PATH
</programlisting>
    If you are using <command>csh</command> or <command>tcsh</command>, then use this command:
<programlisting>
set path = ( /usr/local/pgsql/bin $path )
</programlisting>
   </para>

   <para>
    <indexterm>
     <primary><envar>MANPATH</envar></primary>
    </indexterm>
    To enable your system to find the <application>man</application>
    documentation, you need to add lines like the following to a
    shell start-up file unless you installed into a location that is
    searched by default:
<programlisting>
MANPATH=/usr/local/pgsql/share/man:$MANPATH
export MANPATH
</programlisting>
   </para>

   <para>
    The environment variables <envar>PGHOST</envar> and <envar>PGPORT</envar>
    specify to client applications the host and port of the database
    server, overriding the compiled-in defaults. If you are going to
    run client applications remotely then it is convenient if every
    user that plans to use the database sets <envar>PGHOST</envar>.  This
    is not required, however; the settings can be communicated via command
    line options to most client programs.
   </para>
  </sect2>
 </sect1>

 <sect1 id="supported-platforms">
  <title>Supported Platforms</title>

  <para>
   A platform (that is, a CPU architecture and operating system combination)
   is considered supported by the <productname>PostgreSQL</productname> development
   community if the code contains provisions to work on that platform and
   it has recently been verified to build and pass its regression tests
   on that platform.  Currently, most testing of platform compatibility
   is done automatically by test machines in the
   <ulink url="https://buildfarm.postgresql.org/">PostgreSQL Build Farm</ulink>.
   If you are interested in using <productname>PostgreSQL</productname> on a platform
   that is not represented in the build farm, but on which the code works
   or can be made to work, you are strongly encouraged to set up a build
   farm member machine so that continued compatibility can be assured.
  </para>

  <para>
   In general, <productname>PostgreSQL</productname> can be expected to work on
   these CPU architectures: x86, x86_64, IA64, PowerPC,
   PowerPC 64, S/390, S/390x, Sparc, Sparc 64, ARM, MIPS, MIPSEL,
   and PA-RISC.  Code support exists for M68K, M32R, and VAX, but these
   architectures are not known to have been tested recently.  It is often
   possible to build on an unsupported CPU type by configuring with
   <option>--disable-spinlocks</option>, but performance will be poor.
  </para>

  <para>
   <productname>PostgreSQL</productname> can be expected to work on these operating
   systems: Linux (all recent distributions), Windows (XP and later),
   FreeBSD, OpenBSD, NetBSD, macOS, AIX, HP/UX, and Solaris.
   Other Unix-like systems may also work but are not currently
   being tested.  In most cases, all CPU architectures supported by
   a given operating system will work.  Look in
   <xref linkend="installation-platform-notes"/> below to see if
   there is information
   specific to your operating system, particularly if using an older system.
  </para>

  <para>
   If you have installation problems on a platform that is known
   to be supported according to recent build farm results, please report
   it to <email>pgsql-bugs@lists.postgresql.org</email>.  If you are interested
   in porting <productname>PostgreSQL</productname> to a new platform,
   <email>pgsql-hackers@lists.postgresql.org</email> is the appropriate place
   to discuss that.
  </para>
 </sect1>

 <sect1 id="installation-platform-notes">
  <title>Platform-Specific Notes</title>

  <para>
   This section documents additional platform-specific issues
   regarding the installation and setup of PostgreSQL.  Be sure to
   read the installation instructions, and in
   particular <xref linkend="install-requirements"/> as well.  Also,
   check <xref linkend="regress"/> regarding the
   interpretation of regression test results.
  </para>

  <para>
   Platforms that are not covered here have no known platform-specific
   installation issues.
  </para>

  <sect2 id="installation-notes-aix">
   <title>AIX</title>

   <indexterm zone="installation-notes-aix">
    <primary>AIX</primary>
    <secondary>installation on</secondary>
   </indexterm>

   <para>
    PostgreSQL works on AIX, but AIX versions before about 6.1 have
    various issues and are not recommended.
    You can use GCC or the native IBM compiler <command>xlc</command>.
   </para>

   <sect3>
    <title>Memory Management</title>
    <!-- https://archives.postgresql.org/message-id/603bgqmpl9.fsf@dba2.int.libertyrms.com -->

    <para>
     AIX can be somewhat peculiar with regards to the way it does
     memory management.  You can have a server with many multiples of
     gigabytes of RAM free, but still get out of memory or address
     space errors when running applications.  One example
     is loading of extensions failing with unusual errors.
     For example, running as the owner of the PostgreSQL installation:
<screen>
=# CREATE EXTENSION plperl;
ERROR:  could not load library "/opt/dbs/pgsql/lib/plperl.so": A memory address is not in the address space for the process.
</screen>
    Running as a non-owner in the group possessing the PostgreSQL
    installation:
<screen>
=# CREATE EXTENSION plperl;
ERROR:  could not load library "/opt/dbs/pgsql/lib/plperl.so": Bad address
</screen>
     Another example is out of memory errors in the PostgreSQL server
     logs, with every memory allocation near or greater than 256 MB
     failing.
    </para>

    <para>
     The overall cause of all these problems is the default bittedness
     and memory model used by the server process.  By default, all
     binaries built on AIX are 32-bit.  This does not depend upon
     hardware type or kernel in use.  These 32-bit processes are
     limited to 4 GB of memory laid out in 256 MB segments using one
     of a few models.  The default allows for less than 256 MB in the
     heap as it shares a single segment with the stack.
    </para>

    <para>
     In the case of the <literal>plperl</literal> example, above,
     check your umask and the permissions of the binaries in your
     PostgreSQL installation.  The binaries involved in that example
     were 32-bit and installed as mode 750 instead of 755.  Due to the
     permissions being set in this fashion, only the owner or a member
     of the possessing group can load the library.  Since it isn't
     world-readable, the loader places the object into the process'
     heap instead of the shared library segments where it would
     otherwise be placed.
    </para>

    <para>
     The <quote>ideal</quote> solution for this is to use a 64-bit
     build of PostgreSQL, but that is not always practical, because
     systems with 32-bit processors can build, but not run, 64-bit
     binaries.
    </para>

    <para>
     If a 32-bit binary is desired, set <symbol>LDR_CNTRL</symbol> to
     <literal>MAXDATA=0x<replaceable>n</replaceable>0000000</literal>,
     where 1 &lt;= n &lt;= 8, before starting the PostgreSQL server,
     and try different values and <filename>postgresql.conf</filename>
     settings to find a configuration that works satisfactorily.  This
     use of <symbol>LDR_CNTRL</symbol> tells AIX that you want the
     server to have <symbol>MAXDATA</symbol> bytes set aside for the
     heap, allocated in 256 MB segments.  When you find a workable
     configuration,
     <command>ldedit</command> can be used to modify the binaries so
     that they default to using the desired heap size.  PostgreSQL can
     also be rebuilt, passing <literal>configure
     LDFLAGS="-Wl,-bmaxdata:0x<replaceable>n</replaceable>0000000"</literal>
     to achieve the same effect.
    </para>

    <para>
     For a 64-bit build, set <envar>OBJECT_MODE</envar> to 64 and
     pass <literal>CC="gcc -maix64"</literal>
     and <literal>LDFLAGS="-Wl,-bbigtoc"</literal>
     to <command>configure</command>.  (Options for
    <command>xlc</command> might differ.)  If you omit the export of
    <envar>OBJECT_MODE</envar>, your build may fail with linker errors.  When
    <envar>OBJECT_MODE</envar> is set, it tells AIX's build utilities
    such as <command>ar</command>, <command>as</command>, and <command>ld</command> what
    type of objects to default to handling.
    </para>

    <para>
     By default, overcommit of paging space can happen.  While we have
     not seen this occur, AIX will kill processes when it runs out of
     memory and the overcommit is accessed.  The closest to this that
     we have seen is fork failing because the system decided that
     there was not enough memory for another process.  Like many other
     parts of AIX, the paging space allocation method and
     out-of-memory kill is configurable on a system- or process-wide
     basis if this becomes a problem.
    </para>
   </sect3>
  </sect2>

  <sect2 id="installation-notes-cygwin">
   <title>Cygwin</title>

   <indexterm zone="installation-notes-cygwin">
    <primary>Cygwin</primary>
    <secondary>installation on</secondary>
   </indexterm>

   <para>
    PostgreSQL can be built using Cygwin, a Linux-like environment for
    Windows, but that method is inferior to the native Windows build
    <phrase condition="standalone-ignore">(see <xref linkend="install-windows"/>)</phrase> and
    running a server under Cygwin is no longer recommended.
   </para>

   <para>
    When building from source, proceed according to the Unix-style
    installation procedure (i.e., <literal>./configure;
    make</literal>; etc.), noting the following Cygwin-specific
    differences:

    <itemizedlist>
     <listitem>
      <para>
       Set your path to use the Cygwin bin directory before the
       Windows utilities.  This will help prevent problems with
       compilation.
      </para>
     </listitem>

     <listitem>
      <para>
       The <command>adduser</command> command is not supported; use
       the appropriate user management application on Windows NT,
       2000, or XP.  Otherwise, skip this step.
      </para>
     </listitem>

     <listitem>
      <para>
       The <command>su</command> command is not supported; use ssh to
       simulate su on Windows NT, 2000, or XP. Otherwise, skip this
       step.
      </para>
     </listitem>

     <listitem>
      <para>
       <productname>OpenSSL</productname> is not supported.
      </para>
     </listitem>

     <listitem>
      <para>
       Start <command>cygserver</command> for shared memory support.
       To do this, enter the command <literal>/usr/sbin/cygserver
       &amp;</literal>.  This program needs to be running anytime you
       start the PostgreSQL server or initialize a database cluster
       (<command>initdb</command>).  The
       default <command>cygserver</command> configuration may need to
       be changed (e.g., increase <symbol>SEMMNS</symbol>) to prevent
       PostgreSQL from failing due to a lack of system resources.
      </para>
     </listitem>

     <listitem>
      <para>
        Building might fail on some systems where a locale other than
        C is in use. To fix this, set the locale to C by doing
        <command>export LANG=C.utf8</command> before building, and then
        setting it back to the previous setting after you have installed
        PostgreSQL.
      </para>
     </listitem>

     <listitem>
      <para>
       The parallel regression tests (<literal>make check</literal>)
       can generate spurious regression test failures due to
       overflowing the <function>listen()</function> backlog queue
       which causes connection refused errors or hangs.  You can limit
       the number of connections using the make
       variable <varname>MAX_CONNECTIONS</varname> thus:
<programlisting>
make MAX_CONNECTIONS=5 check
</programlisting>
       (On some systems you can have up to about 10 simultaneous
       connections.)
      </para>
     </listitem>
    </itemizedlist>
   </para>

   <para>
    It is possible to install <command>cygserver</command> and the
    PostgreSQL server as Windows NT services.  For information on how
    to do this, please refer to the <filename>README</filename>
    document included with the PostgreSQL binary package on Cygwin.
    It is installed in the
    directory <filename>/usr/share/doc/Cygwin</filename>.
   </para>
  </sect2>

  <sect2 id="installation-notes-macos">
   <title>macOS</title>

   <indexterm zone="installation-notes-macos">
    <primary>macOS</primary>
    <secondary>installation on</secondary>
   </indexterm>

   <para>
    To build <productname>PostgreSQL</productname> from source
    on <productname>macOS</productname>, you will need to install Apple's
    command line developer tools, which can be done by issuing
<programlisting>
xcode-select --install
</programlisting>
    (note that this will pop up a GUI dialog window for confirmation).
    You may or may not wish to also install Xcode.
   </para>

   <para>
    On recent <productname>macOS</productname> releases, it's necessary to
    embed the <quote>sysroot</quote> path in the include switches used to
    find some system header files.  This results in the outputs of
    the <application>configure</application> script varying depending on
    which SDK version was used during <application>configure</application>.
    That shouldn't pose any problem in simple scenarios, but if you are
    trying to do something like building an extension on a different machine
    than the server code was built on, you may need to force use of a
    different sysroot path.  To do that, set <varname>PG_SYSROOT</varname>,
    for example
<programlisting>
make PG_SYSROOT=<replaceable>/desired/path</replaceable> all
</programlisting>
    To find out the appropriate path on your machine, run
<programlisting>
xcrun --show-sdk-path
</programlisting>
    Note that building an extension using a different sysroot version than
    was used to build the core server is not really recommended; in the
    worst case it could result in hard-to-debug ABI inconsistencies.
   </para>

   <para>
    You can also select a non-default sysroot path when configuring, by
    specifying <varname>PG_SYSROOT</varname>
    to <application>configure</application>:
<programlisting>
./configure ... PG_SYSROOT=<replaceable>/desired/path</replaceable>
</programlisting>
    This would primarily be useful to cross-compile for some other
    macOS version.  There is no guarantee that the resulting executables
    will run on the current host.
   </para>

   <para>
    To suppress the <option>-isysroot</option> options altogether, use
<programlisting>
./configure ... PG_SYSROOT=none
</programlisting>
    (any nonexistent pathname will work).  This might be useful if you wish
    to build with a non-Apple compiler, but beware that that case is not
    tested or supported by the PostgreSQL developers.
   </para>

   <para>
    <productname>macOS</productname>'s <quote>System Integrity
    Protection</quote> (SIP) feature breaks <literal>make check</literal>,
    because it prevents passing the needed setting
    of <literal>DYLD_LIBRARY_PATH</literal> down to the executables being
    tested.  You can work around that by doing <literal>make
    install</literal> before <literal>make check</literal>.
    Most PostgreSQL developers just turn off SIP, though.
   </para>
  </sect2>

  <sect2 id="installation-notes-mingw">
   <title>MinGW/Native Windows</title>

   <indexterm zone="installation-notes-mingw">
    <primary>MinGW</primary>
    <secondary>installation on</secondary>
   </indexterm>

   <para>
    PostgreSQL for Windows can be built using MinGW, a Unix-like build
    environment for Microsoft operating systems, or using
    Microsoft's <productname>Visual C++</productname> compiler suite.
    The MinGW build procedure uses the normal build system described in
    this chapter; the Visual C++ build works completely differently
    and is described in <xref linkend="install-windows"/>.
   </para>

   <para>
    The native Windows port requires a 32 or 64-bit version of Windows
    2000 or later. Earlier operating systems do
    not have sufficient infrastructure (but Cygwin may be used on
    those).  MinGW, the Unix-like build tools, and MSYS, a collection
    of Unix tools required to run shell scripts
    like <command>configure</command>, can be downloaded
    from <ulink url="http://www.mingw.org/"></ulink>.  Neither is
    required to run the resulting binaries; they are needed only for
    creating the binaries.
   </para>

   <para>
     To build 64 bit binaries using MinGW, install the 64 bit tool set
     from <ulink url="https://mingw-w64.org/"></ulink>, put its bin
     directory in the <envar>PATH</envar>, and run
     <command>configure</command> with the
     <command>--host=x86_64-w64-mingw32</command> option.
   </para>

   <para>
    After you have everything installed, it is suggested that you
    run <application>psql</application>
    under <command>CMD.EXE</command>, as the MSYS console has
    buffering issues.
   </para>

   <sect3 id="windows-crash-dumps">
    <title>Collecting Crash Dumps on Windows</title>

    <para>
     If PostgreSQL on Windows crashes, it has the ability to generate
     <productname>minidumps</productname> that can be used to track down the cause
     for the crash, similar to core dumps on Unix. These dumps can be
     read using the <productname>Windows Debugger Tools</productname> or using
     <productname>Visual Studio</productname>. To enable the generation of dumps
     on Windows, create a subdirectory named <filename>crashdumps</filename>
     inside the cluster data directory. The dumps will then be written
     into this directory with a unique name based on the identifier of
     the crashing process and the current time of the crash.
    </para>
   </sect3>
  </sect2>

  <sect2 id="installation-notes-solaris">
   <title>Solaris</title>

   <indexterm zone="installation-notes-solaris">
    <primary>Solaris</primary>
    <secondary>installation on</secondary>
   </indexterm>

   <para>
    PostgreSQL is well-supported on Solaris.  The more up to date your
    operating system, the fewer issues you will experience.
   </para>

   <sect3>
    <title>Required Tools</title>

    <para>
     You can build with either GCC or Sun's compiler suite.  For
     better code optimization, Sun's compiler is strongly recommended
     on the SPARC architecture.  If
     you are using Sun's compiler, be careful not to select
     <filename>/usr/ucb/cc</filename>;
     use <filename>/opt/SUNWspro/bin/cc</filename>.
    </para>

    <para>
     You can download Sun Studio
     from <ulink url="https://www.oracle.com/technetwork/server-storage/solarisstudio/downloads/"></ulink>.
     Many GNU tools are integrated into Solaris 10, or they are
     present on the Solaris companion CD.  If you need packages for
     older versions of Solaris, you can find these tools
     at <ulink url="http://www.sunfreeware.com"></ulink>.
     If you prefer
     sources, look
     at <ulink url="https://www.gnu.org/prep/ftp"></ulink>.
    </para>
   </sect3>

   <sect3>
    <title>configure Complains About a Failed Test Program</title>

    <para>
     If <command>configure</command> complains about a failed test
     program, this is probably a case of the run-time linker being
     unable to find some library, probably libz, libreadline or some
     other non-standard library such as libssl.  To point it to the
     right location, set the <envar>LDFLAGS</envar> environment
     variable on the <command>configure</command> command line, e.g.,
<programlisting>
configure ... LDFLAGS="-R /usr/sfw/lib:/opt/sfw/lib:/usr/local/lib"
</programlisting>
     See
     the <citerefentry><refentrytitle>ld</refentrytitle><manvolnum>1</manvolnum></citerefentry>
     man page for more information.
    </para>
   </sect3>

   <sect3>
    <title>Compiling for Optimal Performance</title>

    <para>
     On the SPARC architecture, Sun Studio is strongly recommended for
     compilation.  Try using the <option>-xO5</option> optimization
     flag to generate significantly faster binaries.  Do not use any
     flags that modify behavior of floating-point operations
     and <varname>errno</varname> processing (e.g.,
     <option>-fast</option>).
    </para>

    <para>
     If you do not have a reason to use 64-bit binaries on SPARC,
     prefer the 32-bit version.  The 64-bit operations are slower and
     64-bit binaries are slower than the 32-bit variants.  On the
     other hand, 32-bit code on the AMD64 CPU family is not native,
     so 32-bit code is significantly slower on that CPU family.
    </para>
   </sect3>

   <sect3>
    <title>Using DTrace for Tracing PostgreSQL</title>

    <para>
     Yes, using DTrace is possible.  See <xref linkend="dynamic-trace"/> for
     further information.
    </para>

    <para>
     If you see the linking of the <command>postgres</command> executable abort with an
     error message like:
<screen>
Undefined                       first referenced
 symbol                             in file
AbortTransaction                    utils/probes.o
CommitTransaction                   utils/probes.o
ld: fatal: Symbol referencing errors. No output written to postgres
collect2: ld returned 1 exit status
make: *** [postgres] Error 1
</screen>
     your DTrace installation is too old to handle probes in static
     functions.  You need Solaris 10u4 or newer to use DTrace.
    </para>
   </sect3>
  </sect2>
 </sect1>

</chapter>
