Chapter 9: Database Sharding & Read-Write Splitting at Scale
Answer-first: Scaling relational databases beyond vertical hardware limits requires read/write splitting with session pinning to eliminate replication lag anomalies, followed by horizontal sharding across isolated partitions. The 2027 SOTA architecture pairs consistent hashing with virtual nodes, 64-bit monotonic Snowflake IDs to prevent B-Tree index fragmentation, and saga orchestration over blocking two-phase commits for cross-shard consistency. Prerequisite: Advanced knowledge of relational database internals (WAL logs, B-Tree indexes, replication lag), consistent hashing algorithms, and distributed transaction semantics is required for this chapter. ...