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Pgpool-II
What it is
Pgpool-II is free, self-hosted middleware for PostgreSQL environments. It sits between PostgreSQL servers and database clients, transparently relaying PostgreSQL protocol messages. Connection pooling reuses server connections with matching properties, reducing connection overhead and supporting throughput. With replicated databases, load balancing distributes SELECT queries across servers. High-availability features include automatic failover, Watchdog, quorum, and split-brain prevention. The software also provides replication, online recovery, connection limiting, and an in-memory query cache. It supports trust, clear-text password, MD5, SCRAM-SHA-256, certificate, PAM, and LDAP authentication; GSSAPI is not supported. SSL can protect frontend and backend communications when enabled, but it is off by default and requires OpenSSL. Binary and source distributions are available, including RPM packages for Red Hat Enterprise Linux and compatible systems. Debian and Ubuntu users are directed to PostgreSQL community packages. Community help comes through mailing lists and GitHub Issues, with commercial support from SRA OSS K.K.
For and against
For
- Free open-source self-hosted middleware
- Automatic failover with quorum protection
- Connection pooling reduces overhead
- SELECT load balancing across replicas
- Multiple authentication methods supported
Against
- GSSAPI authentication is not supported
- SSL is off by default
- Requires self-hosted Linux deployment
The verdict
Pgpool-II combines PostgreSQL pooling, routing, replication, and high-availability controls in a free self-hosted package. Check its authentication and SSL requirements before deploying.
Who it suits
Pgpool-II suits teams running PostgreSQL who need connection pooling, query routing, replication, or failover in a self-hosted deployment. It is also relevant to administrators who need Watchdog and configurable authentication.
Plans and prices
Pgpool-II
open-source software · self-hosted middleware
Read 1 Oct 2026 · pgpool.net
On the record
- Additional features
- Additional features include in-memory query cache, online recovery, connection limiting, Watchdog, and replication.pgpool.net · read 1 Oct 2026
- APT packages
- Users of Debian or Ubuntu are directed to packages provided by the PostgreSQL community.pgpool.net · read 1 Oct 2026
- Authentication
- Supported authentication methods include trust, clear-text password, MD5, SCRAM-SHA-256, certificate, PAM, and LDAP; GSSAPI is not supported.pgpool.net · read 1 Oct 2026
- Connection pooling
- It reuses PostgreSQL server connections with matching properties to reduce connection overhead and improve throughput.pgpool.net · read 1 Oct 2026
- Distribution
- Pgpool-II is available as binary and source formats; the project provides RPM packages for Red Hat Enterprise Linux and compatible distributions.pgpool.net · read 1 Oct 2026
- Documentation
- Official documentation is available in English and Japanese, with tutorials for basic configuration, Watchdog, AWS, and Aurora.pgpool.net · read 1 Oct 2026
- High availability
- It provides automatic failover, Watchdog for Pgpool-II high availability, quorum, and split-brain prevention.pgpool.net · read 1 Oct 2026
- License
- The license permits use, copying, modification, and distribution of the software and documentation for any purpose without a fee.pgpool.net · read 1 Oct 2026
- Load balancing
- For replicated databases, it distributes SELECT queries across servers to reduce load and improve throughput.pgpool.net · read 1 Oct 2026
- Purpose
- Pgpool-II is middleware between PostgreSQL servers and database clients that relays PostgreSQL protocol messages transparently.pgpool.net · read 1 Oct 2026
- Release support
- The project aims to fully support each major release for five years; unsupported releases receive only possible best-effort critical fixes and no formal binary packages.pgpool.net · read 1 Oct 2026
- Security reporting
- The community asks vulnerability reporters to email the project leader privately and does not offer bug bounties.pgpool.net · read 1 Oct 2026
- SSL
- When enabled, SSL protects both frontend and backend communications, but it is off by default and requires OpenSSL support.pgpool.net · read 1 Oct 2026
- Support
- Community support is provided through mailing lists and GitHub Issues, while SRA OSS K.K. offers commercial technical support, consulting, and system integration.pgpool.net · read 1 Oct 2026
