Efficiently Manage database Bloat with pg_repack

3 min read1 day ago

PostgreSQL users often face the challenge of database bloat, which can significantly impact performance. Traditional methods like VACUUM FULL and CLUSTER can be disruptive, but pg_repack offers a solution that works online, ensuring minimal downtime. In this article, we'll explore how to install and configure pg_repack on a PostgreSQL 14 setup running on a Red Hat Enterprise Linux 9 (RHEL 9) system.

What is pg_repack?

pg_repack is a PostgreSQL extension designed to remove bloat from tables and indexes. Unlike CLUSTER and VACUUM FULL, pg_repack operates online without holding an exclusive lock on the processed tables, making it an efficient and less intrusive option.

Installation

Step 1: Download the RPM Package

First, download the pg_repack RPM package for PostgreSQL 14 on RHEL 9:

wget https://download.postgresql.org/pub/repos/yum/14/redhat/rhel-9-x86_64/pg_repack_14-1.5.0-1PGDG.rhel9.x86_64.rpm

Step 2: Install the RPM Package

Next, install the downloaded RPM package:

rpm -iv pg_repack_14-1.5.0-1PGDG.rhel9.x86_64.rpm

Step 3: Verify Installation

You can verify the installation by listing the files included in the package:

rpm -ql pg_repack_14-1.5.0-1PGDG.rhel9.x86_64.rpm | grep bin

Alternatively, use the find command to locate the pg_repack binary:

find / -name pg_repack

Step 4: Update PATH Environment Variable

Add the PostgreSQL bin directory to your PATH:

export PATH=$PATH:/usr/pgsql-14/bin

Make this change permanent by adding it to your ~/.bashrc file:

echo 'export PATH=$PATH:/usr/pgsql-14/bin' >> ~/.bashrc
source ~/.bashrc

Configuration

Step 1: Create the Extension

Connect to your PostgreSQL database and create the pg_repack extension:

psql -c "CREATE EXTENSION pg_repack" -d employee

Step 2: Verify pg_repack Availability

To ensure pg_repack is available, you can list the PostgreSQL binaries:

pg_re

You should see pg_repack listed among the other PostgreSQL binaries:

pg_receivewal   pg_recvlogical  pg_repack       pg_resetwal     pg_restore      pg_rewind

# if you dont see, you may forget to source your bashrc (source ~/.bashrc)

Usage

Basic Usage

To repack a specific database (e.g., employee), use the following command:

pg_repack -d employee

You will see output similar to this:

INFO: repacking table "public.address"
INFO: repacking table "public.city"
INFO: repacking table "public.company"
...

Advanced Options

pg_repack offers several options to customize its behavior. Here are some useful ones:

Repack all databases:

pg_repack -a

Repack a specific table:

pg_repack -t tablename -d employee

Repack tables in a specific schema:

pg_repack -c schemaname -d employee

Move repacked tables to a new tablespace:

pg_repack -s newtablespace -d employee

Order by specific columns:

pg_repack -o "column1, column2" -d employee

For a complete list of options, refer to the pg_repack help:

pg_repack --help

Conclusion

pg_repack is a powerful tool for managing bloat in PostgreSQL databases with minimal downtime. By following the steps outlined in this article, you can easily install and configure pg_repack on your PostgreSQL 14 setup running on RHEL 9. With pg_repack, you can maintain optimal database performance without the need for disruptive maintenance operations. For more detailed and technical articles like this, keep following our blog on Medium. If you have any questions or need further assistance, feel free to reach out in the comments below and directly.