HeliosProxy vs Pgpool-II

HeliosProxy is a self-hosted, programmable PostgreSQL data-plane for routing connections, handling failover, replaying traffic, and supporting database upgrades. It provides session, transaction, and statement pooling, with multiplexing up to 100:1. Routing can account for replica lag, workload type, and failing backends through circuit breaking. Cache options include local memory, Redis-backed storage, and semantic tiers, with invalidation when writes occur. Transaction Replay can move sessions to a new primary and optionally replay reads or transactions when conditions permit, although prepared statements, temporary tables, open cursors, advisory locks, and extended-protocol SET statements are not restored. A WebAssembly plugin runtime offers five hook points, Ed25519 verification, and OCI distribution. The admin console includes topology, plugin, chaos, shadow-execution, and traffic-replay panels. Authentication supports JWT, OAuth 2.0, LDAP, and API keys. HeliosProxy works with PostgreSQL 12+ and compatible databases, and deployment documentation covers Docker, Kubernetes, and standalone setups. It is open source under Apache 2.0 and costs nothing.

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.