Data Consistency

Tombstones Preserve Deletions Across Replica Gaps

A replicated store cannot always represent deletion as immediate absence. If one replica removes a record while another replica is disconnected, erasing every trace of the record also erases the evidence needed to distinguish a deliberate deletion from a replica that simply has not seen recent state. A tombstone keeps that evidence as versioned metadata. Instead of removing the key from the replication domain at once, the system records a deletion marker that participates in reconciliation. A replica carrying an older live value can then compare its state with the marker and discard the obsolete value.