Because Redis runs multithreaded IO multiplexing single thread operation data, it is inevitable that the REDis thread will be occupied when multithreaded IO operation, so to improve efficiency, asynchronous IO operation is provided.
The difference between
Unlink – Non-blocking delete The UNlink operation does not block the CURRENT I/O thread when the REDis is in use
The same
Key deletion is synchronized when DEL and Unlink are deleted
conclusion
When deleting big data, use unlink to avoid blocking other short I/O jobs