CLIENT NO-EVICT, and the connection you must not lose

When Redis is under memory pressure it evicts client connection buffers, and 7.0 lets a connection opt out of being a candidate.

CLIENT NO-EVICT on

# for a connection that must survive pressure: a monitoring
# client, a replica link, an admin session.

# and the related one, for a long-running command that
# should not reset the idle timeout:
CLIENT NO-TOUCH on

# which stops a client's reads from updating the LRU clock
# — useful for a backup or a scan that would otherwise
# make cold keys look hot.

CLIENT NO-TOUCH is the more broadly useful of the two: a nightly scan reading every key otherwise marks all of them as recently used, which inverts the eviction policy for the rest of the day. Both are per-connection and have to be issued after connecting, which means a connection pool needs to apply them on each new connection.