15.2. Requirements

In general, a Linux-Unix platform should be able to run Postgres-XC.

The following software packages are required for building Postgres-XC:

• GNU make version 3.80 or newer is required; other make programs or older GNU make versions will not work. GNU make is often installed under the name gmake; this document will always refer to it by that name. (On some systems GNU make is the default tool with the name make.) To test for GNU make enter:

  gmake --version

• You need an ISO/ANSI C compiler (at least C89-compliant). Recent versions of GCC are recommended, but Postgres-XC can be built using a wide viety of compilers from different vendors.

• tar is required to unpack the source distribution, in addition to either gzip or bzip2.

• The GNU Readline library is used by default. It allows psql (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 --without-readline option to configure. As an alternative, you can often use the BSD-licensed libedit library, originally developed on NetBSD. The libedit library is GNU Readline-compatible and is used if libreadline is not found, or if --with-libedit-preferred is used as an option to configure. If you are using a package-based Linux distribution, be aware that you need both the readline and readline-devel packages, if those are separate in your distribution.

• The zlib compression library is used by default. If you don't want to use it then you must specify the --without-zlib option to configure. Using this option disables support for compressed archives in pg_dump and pg_restore.

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:

• To build the server programming language PL/Perl you need a full Perl installation, including the libperl library and the header files. Since PL/Perl will be a shared library, the libperl library must be a shared library also on most platforms. This appears to be the default in recent Perl versions, but it was not in earlier versions, and in any case it is the choice of whomever installed Perl at your site. If you intend to make more than incidental use of PL/Perl, you should ensure that the Perl installation was built with the usemultiplicity option enabled (perl -V will show whether this is the case).

  If you don't have the shared library but you need one, a message like this will appear during the Postgres-XC build to point out this fact:

  *** Cannot build PL/Perl because libperl is not a shared library.
  *** You might have to rebuild your Perl installation.  Refer to
  *** the documentation for details.

  (If you don't follow the on-screen output you will merely notice that the PL/Perl library object, plperl.so or similar, will not be installed.) If you see this, you will have to rebuild and install Perl manually to be able to build PL/Perl. During the configuration process for Perl, request a shared library.

• To build the PL/Python server programming language, you need a Python installation with the header files and the distutils module. The minimum required version is Python 2.3. Python 3 is supported if it's version 3.1 or later; but see Section 42.1 when using Python 3.

  Since PL/Python will be a shared library, the libpython library must be a shared library also on most platforms. This is not the case in a default Python installation. If after building and installing Postgres-XC you have a file called plpython.so (possibly a different extension), then everything went well. Otherwise you should have seen a notice like this flying by:

  *** Cannot build PL/Python because libpython is not a shared library.
  *** You might have to rebuild your Python installation.  Refer to
  *** the documentation for details.

  That means you have to rebuild (part of) your Python installation to create this shared library.

  If you have problems, run Python 2.3 or later's configure using the --enable-shared flag. On some operating systems you don't have to build a shared library, but you will have to convince the Postgres-XC build system of this. Consult the Makefile in the src/pl/plpython directory for details.

• To build the PL/Tcl procedural language, you of course need a Tcl installation. If you are using a pre-8.4 release of Tcl, ensure that it was built without multithreading support.

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

• You need Kerberos, OpenSSL, OpenLDAP, and/or PAM, if you want to support authentication or encryption using those services.

• To build the Postgres-XC documentation, there is a separate set of requirements; see Section J.2.

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

• GNU Flex and Bison 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 Flex 2.5.31 or later and Bison 1.875 or later. Other lex and yacc programs cannot be used.

• Perl 5.8 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 Perl in any case.

If you need to get a GNU package, you can find it at your local GNU mirror site (see http://www.gnu.org/order/ftp.html for a list) or at ftp://ftp.gnu.org/gnu/.

Also check that you have sufficient disk space. You will need about 100 MB for the source tree during compilation and about 20 MB for the installation directory. An empty database cluster takes about 35 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 150 MB. Use the df command to check free disk space.