When relational database workloads exceed the vertical compute and memory limits of the largest bare-metal server (such as an AWS r6i.32xlarge with 1TB of RAM), systems architects face one of the most fateful infrastructure forks in enterprise software: Manual Sharding or Distributed SQL?
In this comprehensive evaluation, we unpack the trade-offs between Vitess (MySQL sharding proxy), CockroachDB (Raft-consensus distributed SQL), and Google Cloud Spanner (TrueTime atomic clock consensus).
Technical Comparison: Sharding vs Distributed SQL
| Architectural Capability | Vitess (Manual / Proxy Sharding) | CockroachDB / YugabyteDB | Google Cloud Spanner |
|---|---|---|---|
| Consensus Protocol | Master-Replica Semi-Sync | Multi-Raft | Multi-Paxos + TrueTime (GPS / Atomic) |
| Cross-Shard ACID Transactions | Two-Phase Commit (High Latency) | Native Serializable Distributed ACID | Native External Consistency |
| Operational Maintenance | High (Custom resharding logic) | Moderate (Automated rebalancing) | Low (Fully managed cloud service) |
| SQL Compatibility | Native MySQL dialect | Near-complete PostgreSQL dialect | ANSI SQL with Spanner extensions |
