ActiveRecord::ConnectionAdapters::QueryCache::Store

This is the actual query cache store.

It has an internal hash whose keys are either SQL strings, or arrays of two elements [SQL string, binds], if there are binds. The hash values are their corresponding ActiveRecord::Result objects.

Keeping the hash size under max size is achieved with LRU eviction.

The store gets passed a version object, which is shared among the query cache stores of a given connection pool (see ConnectionPoolConfiguration down below). The version value may be externally changed as a way to signal cache invalidation, that is why all methods have a guard for it.