orderBy

If the value is LogStreamName, the results are ordered by log stream name. If the value is LastEventTime, the results are ordered by the event time. The default value is LogStreamName.

If you order the results by event time, you cannot specify the logStreamNamePrefix parameter.

lastEventTimestamp represents the time of the most recent log event in the log stream in CloudWatch Logs. This number is expressed as the number of milliseconds after Jan 1, 1970 00:00:00 UTC. lastEventTimestamp updates on an eventual consistency basis. It typically updates in less than an hour from ingestion, but in rare situations might take longer.