MySQL query caching: limited to a maximum cache size of 128 MB?

Question

My application is very database intensive so I\'ve tried really hard to make sure the application and the MySQL database are working as efficiently as possible together.

Answer 1

Be careful with setting the query_cache_size and limit to high. MySQL only uses a single thread to read from the query cache.

With the query_cache_size set to 4G and query_cache_limit 12M we had a query cache rate of 85% but noticed a recurring spikes in connections.

After changing the query_cache_size to 256M with 64K query_cache_limit the query cache ratio dropped to 50% but the overall performance increased.