Installation¶

Introduction¶

PoWA-archivist is the core component of the PoWA project. It is composed of 2 elements:

an extension named “powa” containing management functions
a module name “powa” that optionally runs a background worker to collect the performance data on the local instance

Prerequisites¶

PostgreSQL >= 9.4
PostgreSQL contrib modules (pg_stat_statements and btree_gist)
PostgreSQL server headers (if compiling from sources)

Installation¶

The recommended way to install PoWA-archivist is to use the packaged version available in the PGDG repositories, which available for GNU/Linux distributions based on Debian/Ubuntu or RHEL/Rocky/Fedora. If you’re using a distribution where no PGDG repository or prepackaged version is available, we document installation from source code.

Installation from PGDG repository¶

On Debian/Ubuntu, please refer to the APT PGDG repository documentation <https://apt.postgresql.org> for the initial setup (which should already be done if you have PostgreSQL installed), and simply install postgresql-XY-powa. For instance, if you’re using PostgreSQL 15:

sudo apt-get install postgresql-15-powa

On RHEL/Rock/Fedora, please refer to the YUM PGDG repository documentation <https://yum.postgresql.org> for the iniial setup (which should already be done if you have PostgreSQL installed), and simply install powa_XY. For instance, if you’re using PostgreSQL 15:

sudo dnf install powa_15

Note

Package names for older PostgreSQL version may vary and not contain an _ between the package name and the PostgreSQL major version.

Installation from sources¶

On Debian, the PostgreSQL server headers are installed via the postgresql-server-dev-XY package:

sudo apt-get install postgresql-server-dev-15 postgresql-contrib-15

On RPM-based distros:

sudo dnf install postgresql15-devel postgresql15-contrib

You also need a C compiler and other standard development tools.

On Debian, these can be installed via the build-essential package:

apt-get install build-essential

On RPM-based distros, the “Development Tools” can be used:

yum groupinstall "Development Tools"

Grab the latest release, and install it:

wget https://github.com/powa-team/powa-archivist/archive/REL_4_1_4.tar.gz -O powa-archivist-REL_4_1_4.tar.gz
tar zxvf powa-archivist-REL_4_1_4.tar.gz
cd powa-archivist-REL_4_1_4

Compile and install it:

make
sudo make install

Note

Make sure that sudo refers to the same PostgreSQL headers. Using pg_config and sudo pg_config should produce the same output.

It should output something like the following :

/bin/mkdir -p '/usr/share/postgresql-15/extension'
/bin/mkdir -p '/usr/share/postgresql-15/extension'
/bin/mkdir -p '/usr/lib64/postgresql-15/lib64'
/bin/mkdir -p '/usr/share/doc/postgresql-15/extension'
/usr/bin/install -c -m 644 powa.control '/usr/share/postgresql-15/extension/'
/usr/bin/install -c -m 644 powa--2.0.sql '/usr/share/postgresql-15/extension/'
/usr/bin/install -c -m 644 README.md '/usr/share/doc/postgresql-15/extension/'
/usr/bin/install -c -m 755  powa.so '/usr/lib64/postgresql-15/lib64/'

PostgreSQL installation¶

Create the PoWA database and create the required extensions, with the following statements:

CREATE EXTENSION pg_stat_statements;
CREATE EXTENSION btree_gist;
CREATE EXTENSION powa;

Example:

bash-4.1$ psql
psql (15.2)
Type "help" for help.
postgres=# create database powa;
CREATE DATABASE
postgres=# \c powa
You are now connected to database "powa" as user "postgres".
powa=# create extension pg_stat_statements ;
CREATE EXTENSION
powa=# create extension btree_gist ;
CREATE EXTENSION
powa=# create extension powa;
CREATE EXTENSION

As PoWA-archivist can provide a background worker, the library must be loaded at server start time if local metric collection is wanted.

For this, modify the postgresql.conf configuration file, and add powa and pg_stat_statements to the shared_preload_libraries parameter:

shared_preload_libraries = 'pg_stat_statements,powa'

If possible, activate track_io_timing too:

track_io_timing = on

PostgreSQL should then be restarted.

Warning

Since PoWA 4, you need to specify powa in the shared_preload_libraries configuration ONLY if you want to store the performance data locally. For remote storage, please see the Remote setup documentation. The pg_stat_statements extension (as all other Stats Extensions) still required to be configured in the shared_preload_libraries setting.

If you’re setting up a repository database for a remote server, you can also entirely skip the pg_stat_statements configuration and the restart.

Major PostgreSQL Upgrade¶

Warning

There is a known issue with all PostgreSQL versions when using pg_upgrade on a instance having custom background workers, like PoWA in local setup mode: PostgreSQL doesn’t prevent the background workers from doing their usual activity during pg_upgrade. It means that if the background worker performs some write when pg_upgrade expects that no write would happen, the resulting cluster can be corrupted. It’s unfortunately not something that can be fixed from PoWA itself.

If you want to perform a pg_upgrade of any instance having PoWA setup in local mode, you need to disable it before doing the pg_upgrade, and re-enable it once the upgrade is finished.