- Published on
Why a database index can exist and still fail to speed up a query, including selectivity, row estimates, composite index order, post-index filters, ORDER BY LIMIT behavior, partial indexes, and production verification.
Performance
All Posts
- software-engineering (24)
- backend (23)
- reliability (20)
- distributed-systems (15)
- databases (12)
- production-systems (8)
- architecture (7)
- performance (7)
- api-design (6)
- microservices (5)
- fundamentals (4)
- observability (4)
- debugging (4)
- sql (4)
- testing (3)
- best-practices (3)
- cascading-failures (3)
- systems (3)
- code-review (2)
- engineering-process (2)
- career (1)
- postgresql (1)
- production (1)
- Published on
Why production caches return stale or contradictory data, including cache-aside races, invalidation gaps, TTL drift, local cache divergence, write-through trade-offs, and safer rollout checks.