Described is a technology in which an anchor value is determined, for example to synchronize a destination database or data store with modifications made to a source database. The new anchor value is determined in a manner that excludes modifications corresponding to any uncommitted transactions. The new anchor value may be based on a counter value or a date and time value stored with each modification. The new anchor value may be determined by comparing a first set of committed modifications that do not include uncommitted modifications against a second set of modifications that includes committed modifications and uncommitted modifications. Alternatively, the new anchor value may be determined from the earliest start date and time among the modifications that are part of any uncommitted transactions. The anchor may be used (e.g., via queries) to enumerate modifications for synchronization, and also for detecting conflicts between the source and destination databases.