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Database / ValKey Interview questions

What is the difference between WAIT and replica acknowledgment in Valkey?

Replica acknowledgment, sent as REPLCONF ACK, is the continuous, low-level heartbeat a replica sends the primary reporting the replication offset it has applied so far; it's used internally for tracking lag and enabling partial resynchronization.

WAIT numreplicas timeout is a client-facing command that blocks the caller until at least numreplicas have acknowledged all writes issued so far, or the timeout expires, giving an application a way to opt into a stronger durability guarantee on top of Valkey's normally asynchronous replication.

WAIT is used by a client to...
REPLCONF ACK messages are sent...

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