Query Cache

Definitions

1. A mechanism that stores the result set of a previously executed query keyed by the query text (and sometimes its parameters), returning cached results on subsequent identical queries instead of re-executing against the database. MySQL's built-in query cache (removed in 8.0) and application-layer caches like Redis-backed query results are common implementations.

   In plain English: A saved copy of a database query's results so the same question can be answered instantly without asking the database again.

   Example: "The query cache was giving us stale results after writes because invalidation wasn't hooked up to the mutation path."

Related Terms

• Connection Pooling
• N+1 Query Problem
• LRU Cache
• Stale-While-Revalidate
• Query Plan
• Index Scan vs Seq Scan
• ETag
• Partitioning
• Cache Stampede
• Disk Cache
• Inline Cache
• KV Store
• Memcached