postgresql/README.rpm-dist

README.rpm-dist
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Version 9.2, for the PostgreSQL 9.2 RPM set.
Devrim Gündüz <devrim@gunduz.org>
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Contents:
 1.)	Introduction and QuickStart
 2.)	Upgrading an installation
 3.)	PostgreSQL RPM packages and rationale
 4.)	Starting multiple postmasters
 5.)	Regression Testing
 6.)	Starting postmaster automatically on startup
 7.)	Grand Unified Configuration(GUC) File
 8.)	Logging set up
 9.)	Rebuilding from the source RPM
10.)	Contrib files
11.)	Further Information Resource

INTRODUCTION
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This document exists to explain the layout of the RPMs for PostgreSQL, to 
describe various RPM specifics, and to document special features found
in the RPMset.

This document is written to be applicable to version 9.2 of PostgreSQL,
which is the current version of the RPMs as of this writing. More to the 
point, versions prior to 9.2 are not documented here.

This document is intended for use only with the RPMs supplied in Red Hat
Enterprise Linux, CentOS and Fedora.  Note that there are also "PGDG"
RPMs available directly from the upstream PostgreSQL project.  Those are
slightly different.

QUICKSTART (note that this requires postgresql-server installed)
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For a fresh installation, you will need to initialize the cluster first. Run:

	postgresql-setup initdb

as root, and it will prepare a new database cluster for you. Then you will 
need to start PostgreSQL. Again as root, run:

	systemctl start postgresql.service

This command will start a postmaster that willl listen on localhost and Unix 
socket 5432 only.  Edit /var/lib/pgsql/data/postgresql.conf and pg_hba.conf 
if you want to allow remote access -- see the section on Grand Unified 
Configuration.

You will probably also want to do

	systemctl enable postgresql.service

so that the postmaster is automatically started during future reboots.

The file /var/lib/pgsql/.bash_profile is packaged to help with the 
setting of environment variables. You may edit this file, and it won't be
overwritten during an upgrade.  However, enhancements and bugfixes may 
be added to this file, so be sure to check .bash_profile.rpmnew after 
upgrading.

The user 'postgres' is created during installation of the server subpackage.
This user by default is UID and GID 26. The user has the default shell set to
bash, and the home directory set to /var/lib/pgsql.  This user also has no
default password, so the only way to become this user is to su to it from root.
If you want to be able to su to it from a non-root account or log in directly
as 'postgres' you will need to set a password using passwd.

UPGRADING AN INSTALLATION
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For a minor-version upgrade (such as 9.2.1 to 9.2.2), just install the
new RPMs; there's usually nothing more to it than that.  Upgrading
across a major release of PostgreSQL (for example, from 9.1.x to 9.2.x)
requires more effort.

If you are upgrading across more than one major release of PostgreSQL
(for example, from 8.3.x to 9.0.x), you will need to follow the "traditional"
dump and reload process to bring your data into the new version.  That is:
*before* upgrading, run pg_dumpall to extract all your data into a SQL file.
Shut down the old postmaster, upgrade to the new version RPMs, initdb,
and run the dump file through psql to restore your data.

In some major releases, the RPMs also support in-place upgrade from the
immediately previous major release.  Currently, you can upgrade in-place
from 9.1.x to 9.2.x.  This is much faster than a dump and reload.
To do an in-place upgrade:
* shut down the old postmaster ("systemctl stop postgresql.service")
* optionally make a backup of /var/lib/pgsql/data/ (recommended!)
* install the new version's RPMs (install all the ones you had before,
  plus postgresql-upgrade)
* as root, run "postgresql-setup upgrade"
* update the configuration files /var/lib/pgsql/data/*.conf with any
  customizations you had before (your old configuration files are in
  /var/lib/pgsql/data-old/)
* as root, run "systemctl start postgresql.service"
* the postgresql-upgrade RPM can be removed after the update is complete,
  as can /var/lib/pgsql/data-old/

NOTE: The in-place upgrade process is new and relatively poorly tested,
so if your data is critical it's a really good idea to make a tarball
backup of /var/lib/pgsql/data/ before running the upgrade.  This will
let you get back to where you were in case of disaster.

POSTGRESQL RPM PACKAGES AND RATIONALE.
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PostgreSQL is split up into multiple packages so that users can 'pick and
choose' what pieces are needed, and what dependencies are required.

The RPMset is packaged in the following subpackages:

postgresql:		Key client programs and documentation
postgresql-libs:	Client shared libraries
postgresql-server:	Server executables and data files
postgresql-devel:	Development libraries and include files
postgresql-test:	The regression tests and associated files
postgresql-upgrade:	Support files for upgrading from previous major version
postgresql-docs:	Extra documentation, such as the tutorial files
postgresql-contrib:	Add-on loadable modules and programs
postgresql-plperl:	PL/Perl procedural language
postgresql-plpython:	PL/Python procedural language (for Python 2)
postgresql-plpython3:	PL/Python procedural language (for Python 3)
postgresql-pltcl:	PL/Tcl procedural language

You have to install postgresql and postgresql-libs to do anything.
postgresql-server is needed unless you only plan to use the clients to work
with a remote PostgreSQL server. The others are optional.

Note that there are no postgresql-perl, postgresql-jdbc, postgresql-odbc,
postgresql-python, postgresql-tcl, or postgresql-tk subpackages any longer.
Those programs have been split off into separate source distributions.
They are still available, but in some cases not under those RPM names.

RPM FILE LOCATIONS.
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To be in compliance with the Linux FHS, the PostgreSQL RPMs install files in
a manner not consistent with most of the PostgreSQL documentation.  According
to the standard PostgreSQL documentation, PostgreSQL is installed under the
directory /usr/local/pgsql, with executables, source, and data existing in
various subdirectories.

Different distributions have different ideas of some of these file locations.
In particular, the documentation directory can be /usr/doc, /usr/doc/packages,
/usr/share/doc, /usr/share/doc/packages, or some other similar path.

However, the Red Hat / CentOS / Fedora RPM's install the files like 
this:

Executables:		/usr/bin
Libraries:		/usr/lib (or /usr/lib64 on 64-bit machines)
Documentation:		/usr/share/doc/postgresql-docs-x.y.z/html
Contrib documentation:	/usr/share/doc/postgresql-contrib-x.y.z
Source:			not installed
Data:			/var/lib/pgsql/data
Backup area:		/var/lib/pgsql/backups
Templates:		/usr/share/pgsql
Procedural Languages:	/usr/lib/pgsql or /usr/lib64/pgsql
Development Headers:	/usr/include/pgsql
Other shared data:	/usr/share/pgsql
Regression tests:	/usr/lib/pgsql/test/regress  (in the -test package)
			or /usr/lib64/pgsql/test/regress

While it may seem gratuitous to place these files in different locations, the
FHS requires it -- distributions should not ever touch /usr/local.  It may
also seem like more work to keep track of where everything is -- but, that's
the beauty of RPM -- you don't have to keep track of the files, RPM does it
for you.

These RPMs are designed to be LSB-compliant -- if you find this not to be the
case, please let us know by way of the pgsqlrpms-hackers@pgfoundry.org
mailing list.

MULTIPLE POSTMASTERS
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The postgresql-server RPM contains a systemd "unit" file, postgresql.service,
that is used to start the PostgreSQL postmaster.  If you need to run multiple
postmasters on one machine, you can create additional unit files derived
from this one.

As an example, let us create a secondary postmaster called, creatively enough,
'secondary'.  Here are the steps:
1.)	Create a file named /etc/systemd/system/secondary.service.
	(Note that user-created unit files must go into /etc not /lib!)
	Put these lines in it:
		.include /lib/systemd/system/postgresql.service
		[Service]
		Environment=PGPORT=nnnn
		Environment=PGDATA=/path/to/data/directory
	Replace "nnnn" and "/path/to/data/directory" with appropriate
	settings that don't conflict with any other postmaster.
2.)	As root, do "/bin/systemctl daemon-reload" to ensure systemd has
	noticed your updates to the service file.
3.)	Create the target PGDATA directory, making sure that its parent
	directories have appropriate ownership and permissions.
4.)	Initdb the target PGDATA with 'postgresql-setup initdb secondary'.
5.)	Edit postgresql.conf in the target PGDATA to change settings as needed.
6.)	Start the new postmaster with 'systemctl start secondary.service'.
	You will probably also want to do 'systemctl enable secondary.service'
	so that the new postmaster is automatically started in future reboots.

When doing a major-version upgrade of a secondary postmaster, add the
service name to the postgresql-setup command, for example 'postgresql-setup
upgrade secondary'.  This will let postgresql-setup find the correct data
directory from the service file.

If you are running SELinux in enforcing mode (which is highly recommended,
particularly for network-exposed services like PostgreSQL) you will need to
adjust SELinux policy to allow the postmaster to use non-default PGPORT or
PGDATA settings.  To allow use of a non-default port, say 5433, do this
as root:
	semanage port -a -t postgresql_port_t -p tcp 5433
To allow use of a non-default data directory, say /special/pgdata, do:
	semanage fcontext -a -t postgresql_db_t "/special/pgdata(/.*)?"
If you already created the directory, follow that with:
	restorecon -R /special/pgdata
These settings are persistent across reboots.  For more information
see "man semanage".

REGRESSION TESTING
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If you install the postgresql-test RPM then you can run the PostgreSQL
regression tests.  These tests stress your database installation and produce
results that give you assurances that the installation is complete, and that
your database machine is up to the task.

To run the regression tests under the RPM installation, make sure that the
postmaster has been started (if not, su to root and do "systemctl start
postgresql.service"), su to postgres, cd to /usr/lib/pgsql/test/regress
(or /usr/lib64/pgsql/test/regress on a 64-bit machine),
and execute "make check".
This command will start the regression tests and will both show the
results to the screen and store the results in the file regress.out.

If any tests fail, see the file regression.diffs in that directory for details,
and read the "Regression Tests" section of the PostgreSQL documentation to
find out whether the differences are actually significant.  If you need help
interpreting the results, contact the pgsql-general list at 
postgresql.org.

After testing, run "make clean" to remove the files generated by the test
script.  Then you can remove the postgresql-test RPM, if you wish.

STARTING POSTMASTER AUTOMATICALLY AT SYSTEM STARTUP
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Fedora / Red Hat / CentOS use the systemd package to manage server startup.
A systemd unit file for PostgreSQL is provided in the server package, as
/lib/systemd/system/postgresql.service.  To start the postmaster manually,
as root run
	systemctl start postgresql.service
To shut the postmaster down,
	systemctl stop postgresql.service
These two commands only change the postmaster's current status.  If you
want the postmaster to be started automatically during future system startups,
run
	systemctl enable postgresql.service
To undo that again,
	systemctl disable postgresql.service
See "man systemctl" for other possible subcommands.

GRAND UNIFIED CONFIGURATION (GUC) FILE
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The PostgreSQL server has many tunable parameters -- the file 
/var/lib/pgsql/data/postgresql.conf is the master configuration file for the
whole system.  

The RPM ships with a mostly-default file -- you will need to tune the
parameters for your installation.  In particular, you might want to allow
nonlocal TCP/IP socket connections -- in order to allow these, you will need
to edit the postgresql.conf file.  The line in question contains the string 
'listen_addresses' -- you need to both uncomment the line and set the value
to '*' to get the postmaster to accept nonlocal connections.  You'll also need
to adjust pg_hba.conf appropriately.

LOGGING SET UP
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By default, the postmaster's stderr log is directed into files placed in a
pg_log subdirectory of the data directory (ie, /var/lib/pgsql/data/pg_log).
The out-of-the-box configuration rotates among seven files, one for each
day of the week.  You can adjust this by changing postgresql.conf settings.

REBUILDING FROM SOURCE RPM
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If your distribution is not supported by the binary RPMs from PostgreSQL.org, 
you will need to rebuild from the source RPM.

If you have not previously rebuilt any RPMs, set up the required environment:
make a work directory, say ~/rpmwork, then cd into it and do
	mkdir BUILD BUILDROOT RPMS SOURCES SPECS SRPMS
Then make a file ~/.rpmmacros containing
	%_topdir <full path to work directory here>

Download the postgresql .src.rpm for the release you want and place it in
the SRPMS subdirectory, then cd there and execute
	rpmbuild --rebuild postgresql-nnn.src.rpm
The results will appear under the RPMS subdirectory.

You will have to have a full development environment to rebuild the RPM set.
If rpmbuild complains of lack of certain packages, install them and try
again.  In some cases, you can disable features to avoid needing some
development packages, as detailed next.

This release of the RPMset includes the ability to conditionally build 
sets of packages.  The parameters, their defaults, and the meanings are:

beta		0	#build with cassert and do not strip the binaries
runselftest	1	#do "make check" during the build
test		1	#build the postgresql-test package
upgrade		1	#build the postgresql-upgrade package
plpython	1	#build the PL/Python procedural language package
plpython3	1	#build the PL/Python3 procedural language package
pltcl		1	#build the PL/Tcl procedural language package
plperl		1	#build the PL/Perl procedural language package
ssl		1	#build with OpenSSL support
kerberos	1	#build with Kerberos 5 support
ldap		1	#build with LDAP support
nls		1	#build with national language support
pam		1	#build with PAM support
sdt		1	#build with SystemTap support
xml		1	#build with XML support
pgfts		1	#build with --enable-thread-safety
selinux		1	#build contrib/selinux
uuid		1	#build contrib/uuid-ossp

To use these defines, invoke a rebuild like this:
rpmbuild --rebuild --define 'plpython 0' --define 'pltcl 0' \
	--define 'test 0' --define 'runselftest 0' --define 'kerberos 0' \
	postgresql-9.2.0-1.src.rpm
This line would disable the plpython, pltcl, and test subpackages, disable
the regression test run during build, and disable kerberos support.

You might need to disable runselftest if there is an installed version of
PostgreSQL that is a different major version from what you are trying to
build.  The self test tends to pick up the installed libpq.so shared library
in place of the one being built :-(, so if that isn't compatible the test will
fail.  Also, you can't use runselftest when doing the build as root.

More of these conditionals will be added in the future.

CONTRIB FILES
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The contents of the contrib tree are packaged into the -contrib subpackage
and are processed with make and make install.  There is documentation in
/usr/share/doc/postgresql-contrib-VERSION for these modules.  Most of the
modules are in /usr/lib/pgsql (or /usr/lib64/pgsql) for loadable
modules, and binaries are in /usr/bin.  In the future these files may be
split out, depending upon function and dependencies.

MORE INFORMATION
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You can get more information at http://www.postgresql.org and 
http://yum.pgsqlrpms.org

Please help make this packaging better -- let us know if you find problems, or
better ways of doing things. You can reach us by e-mail at
pgsqlrpms-hackers@pgfoundry.org
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