Snapshot Isolation
Vertica can run any SQL query in snapshot isolation mode in order to obtain the fastest possible execution. To be precise, snapshot isolation mode is actually a form of a historical query. The syntax is:
AT EPOCH LATEST SELECT...
The command queries all data in the database up to but not including the current epoch without holding a lock or blocking write operations, which could cause the query to miss rows loaded by other users up to (but no more than) a specific number of minutes before execution.