Indicates how to choose the timestamp at which to read the data for Cloud Spanner read-only transactions. If your application can tolerate some staleness when reading data, you can use a stale read, which can execute much faster when compared to reading the latest data.
public enum TimestampBoundMode
Executes all reads at a timestamp that is
Guarantees that all writes that have committed more than the specified number of seconds ago are visible. Because Cloud Spanner chooses the exact timestamp, this mode works even if the client's local clock is substantially skewed from Cloud Spanner commit timestamps.
Useful for reading at nearby replicas without the distributed timestamp negotiation overhead of MaxStaleness.
Read data at a timestamp >=
Useful for reading the freshest data available at a nearby replica, while bounding the possible staleness if the local replica has fallen behind.
Note that this option can only be used in single-use. transactions.
Executes all reads at a timestamp >=
This is useful for requesting fresher data than some previous read, or data that is fresh enough to observe the effects of some previously committed transaction whose timestamp is known.
Note that this option can only be used in single-use transactions.
Executes all reads at the given timestamp. Unlike other modes, reads at a specific timestamp are repeatable; the same read at the same timestamp always returns the same data. If the timestamp is in the future, the read will block until the specified timestamp, modulo the read's deadline.
Useful for large scale consistent reads such as mapreduces, or for coordinating many reads against a consistent snapshot of the data.
Read at a timestamp where all previously committed transactions are visible.