PmaControl logo PmaControl
Resources › MySQL optimization center › MySQL Query Cache

MySQL Query Cache

Structured Markdown documentation to diagnose, measure, and optimize MySQL.

This page is original PmaControl documentation. It keeps a practical index structure for MySQL optimization work, without copying third-party content or depending on an external product.

Role

The query cache is a historical feature. It can speed up some repeated reads, but it introduces strong contention on modern write-heavy workloads.

Related Variables

  • query_cache_type
  • query_cache_size
  • query_cache_limit
  • query_cache_min_res_unit

Recommendation

On MySQL 5.7, disabling it is often preferable for concurrent applications. On MySQL 8, it no longer exists. If an old platform still uses it, measure hits, invalidations, and waits before deciding.

SHOW VARIABLES LIKE 'query_cache%';
SHOW GLOBAL STATUS LIKE 'Qcache%';