DBLE vs PgBouncer

DBLE is free, open-source middleware for scaling MySQL through sharding. It uses the MySQL protocol and can replace MySQL in many cases without application code changes. Teams can configure hash, modulo, time-based, range-based, or custom sharding, along with global and ER tables. DBLE lists query routing, connection pooling, load balancing, automatic failover, read/write separation, master-slave expansion, and ZooKeeper cluster deployment. SQL support includes SQL 92 and MySQL dialect features such as joins, unions, grouping, ordering, and distinct queries; some features remain on its roadmap. Query optimization addresses global-table joins, sharded tables, ER relations, and subqueries. Distributed transactions use two-phase commit in normal or XA modes, with XA depending on MySQL 5.7 XA transactions, backend availability, and disk reliability. Security controls include password encryption, IP allowlists, and SQL denylists. Explain plans, MySQL-compatible slow logs, and slow-query reports support operations. DBLE is self-hosted on Linux and GPL-2.0 licensed. The open-source plan costs nothing.

PgBouncer is a self-hosted connection pooler for PostgreSQL. It reuses server connections to lessen the performance cost of opening new ones, and offers session, transaction, and statement pooling. Statement pooling does not allow multi-statement transactions. PgBouncer can send connections to databases on different hosts, but it has no built-in multi-host load balancing or failover detection; DNS round-robin, external TCP load balancers, DNS changes, or external tools are described as alternatives. It can track protocol-level prepared statements in transaction and statement modes when max_prepared_statements is non-zero. Authentication options include client certificates, SCRAM-SHA-256, LDAP, PAM, and HBA-based configuration. The features page lists default memory needs of 2 kB per connection. PgBouncer is free, with source releases and references to native packages and RPM and Debian repositories. It runs on Linux and Windows; MinGW is the documented supported Windows build environment. Building requires Libevent 2.0 or later, pkg-config, and a C11-capable compiler; TLS support also requires OpenSSL.