DBLE vs PgDog

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.

PgDog is a PostgreSQL connection pooler, load balancer, and database sharder designed to scale databases without application changes. It multiplexes many application connections across fewer PostgreSQL server connections and supports SET, LISTEN/NOTIFY, and advisory locks. Read queries can be distributed across replicas while writes go to the primary, with health checks and failover detection. Sharding keys guide query routing; queries without a key can run across databases in parallel. Cross-shard transactions use PostgreSQL prepared transactions and two-phase commit, with automatic rollback on errors. PgDog can copy data and stream row changes to another database without pausing query traffic. Deployment options include Kubernetes Helm, Docker, AWS ECS Terraform, pre-built binaries, and source. Releases include Linux arm64 and amd64, Apple Silicon Mac, and Debian packages; the macOS binary is unsigned. The project is free and open source under AGPL-3.0, and documentation says internal use does not require sharing source code. Enterprise support includes architecture reviews, a dedicated Slack channel, and an SLA promising a response within 15 minutes.