This read-write INTEGER selects whether polling of the History databases is anchored to an admin-specified time, lockUserTime using the dcUserTime object, or automatically follows the current time, lockRealTime using the dcRealTime object. An admin sets this to lockUserTime when every SNMP poll needs to consistently return the same historical window, for example while auditing a specific incident, rather than having the retrievable window silently slide forward with real time. For example, setting ctLockMethod to lockUserTime(1) and then setting dcUserTime to the moment of an outage lets an admin repeatedly poll and cross-check the same fixed set of history rows for that incident.