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Pgpool-II

pgpool.net

Free plan LinuxSelf-hosted
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Spec score 7.4 #21 of 31 in Database Proxy Software

What it is

Pgpool-II is free, self-hosted middleware positioned between PostgreSQL servers and database clients. It relays PostgreSQL protocol messages, reuses matching server connections to reduce overhead, and distributes SELECT queries across replicated databases. High-availability functions include automatic failover, Watchdog, quorum, and split-brain prevention. Additional features include replication, online recovery, connection limiting, and an in-memory query cache. The project is available in binary and source formats, including RPM packages for Red Hat Enterprise Linux and compatible distributions; Debian and Ubuntu users are directed to PostgreSQL community packages. Authentication supports trust, clear-text password, MD5, SCRAM-SHA-256, certificates, PAM, and LDAP, but not GSSAPI. SSL can protect frontend and backend traffic when enabled; it is off by default and requires OpenSSL support. Community assistance is available through mailing lists and GitHub Issues, while SRA OSS K.K. offers commercial support, consulting, and integration. The license permits use, modification, copying, and distribution without a fee.

Spec sheet

Purpose
Pgpool-II is middleware between PostgreSQL servers and database clients that relays PostgreSQL protocol messages transparently.Read 1 Oct 2026 · pgpool.net
Support
Community support is provided through mailing lists and GitHub Issues, while SRA OSS K.K. offers commercial technical support, consulting, and system integration.Read 1 Oct 2026 · pgpool.net
License
The license permits use, copying, modification, and distribution of the software and documentation for any purpose without a fee.Read 1 Oct 2026 · pgpool.net
Additional features
Additional features include in-memory query cache, online recovery, connection limiting, Watchdog, and replication.Read 1 Oct 2026 · pgpool.net
APT packages
Users of Debian or Ubuntu are directed to packages provided by the PostgreSQL community.Read 1 Oct 2026 · pgpool.net
Authentication
Supported authentication methods include trust, clear-text password, MD5, SCRAM-SHA-256, certificate, PAM, and LDAP; GSSAPI is not supported.Read 1 Oct 2026 · pgpool.net
Connection pooling
It reuses PostgreSQL server connections with matching properties to reduce connection overhead and improve throughput.Read 1 Oct 2026 · pgpool.net
Distribution
Pgpool-II is available as binary and source formats; the project provides RPM packages for Red Hat Enterprise Linux and compatible distributions.Read 1 Oct 2026 · pgpool.net
Documentation
Official documentation is available in English and Japanese, with tutorials for basic configuration, Watchdog, AWS, and Aurora.Read 1 Oct 2026 · pgpool.net
High availability
It provides automatic failover, Watchdog for Pgpool-II high availability, quorum, and split-brain prevention.Read 1 Oct 2026 · pgpool.net
Load balancing
For replicated databases, it distributes SELECT queries across servers to reduce load and improve throughput.Read 1 Oct 2026 · pgpool.net
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.Read 1 Oct 2026 · pgpool.net
Security reporting
The community asks vulnerability reporters to email the project leader privately and does not offer bug bounties.Read 1 Oct 2026 · pgpool.net
SSL
When enabled, SSL protects both frontend and backend communications, but it is off by default and requires OpenSSL support.Read 1 Oct 2026 · pgpool.net

Plans and prices

Pgpool-II Free open-source software · self-hosted middleware Read 1 Oct 2026 · pgpool.net

Every Pgpool-II plan and price →

Strong points and limits

Strong points

  • Free open-source self-hosted middleware
  • Automatic failover and split-brain prevention
  • Connection pooling reduces overhead
  • Load-balances SELECT queries
  • Multiple authentication methods supported

Limits

  • Supports PostgreSQL only
  • SSL is off by default
  • GSSAPI authentication is unsupported
  • Requires self-hosted Linux deployment

Who it suits

It suits PostgreSQL administrators who need self-hosted pooling, query routing, replication, or failover middleware. Teams should be comfortable managing Linux deployment and configuration.

Verdict

Pgpool-II provides a broad set of PostgreSQL pooling, routing, and availability functions without a license fee. Its self-hosted operation and configuration requirements make deployment responsibility part of the choice.

Where Specifiction places it

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