Scaling Database Reads

Scaling reads involves offloading database queries from primary write storage using caches, replicas, and index optimization.

1. Reading Architectures

• Read Replicas:

Primary DB handles writes and replicates updates asynchronously to multiple read replicas. Queries are load-balanced across replicas.

• Cache Invalidation Patterns:
• Write-Aside (Cache-Aside): Application queries the cache. If a cache miss occurs, it queries the DB and updates the cache.
• Write-Through: Application writes to the cache, which writes to the database immediately.
• Write-Behind (Write-Back): Application writes to the cache. The cache buffers updates and writes to the DB asynchronously.

2. Spatial & Index Tuning

Create composite indexes tailored to specific query filter combinations to avoid database range scans.

3. References & Tech Blogs

• AWS Architecture Blog: Database Read Scaling Strategies
• Redis: Cache-Aside vs Write-Through Patterns