Hi,
Currently, ActiveSupport::Cache::RedisCacheStore uses the DEL command for deleting cache entries.
However, Redis provides two commands for deleting keys: the familiar DEL command and the UNLINK command.
While UNLINK is very similar to DEL, it reclaims the memory asynchronously in a separate thread, unlike DEL which does so synchronously.
(Essentially, UNLINK immediately unlinks the keys from the keyspace, and the actual memory removal happens later in the background.)
Therefore, I suggest that RedisCacheStore consider using UNLINK instead of DEL to potentially improve performance by avoiding blocking operations.
[ref]