When an application writes log blocks to a log stream, system logger generates a time stamp for the block, in both local and Coordinated universal time (UTC), showing the time that system logger processed the block. The local time stamp is the local time of the system where the IXGWRITE was issued. Note that local time stamps can repeat because of daylight saving time. In such a case of duplicate time stamps, system logger will return the first block with a matching time stamp that it finds.
Log blocks are placed in the log stream in the order they were received by system logger. System logger generates a UTC time stamp for each log block it receives. Note that the order in which the log blocks are received is not necessarily the same order in which log blocks were written, because when multiple applications write to the same log stream, the log blocks might not be received in the same order that they were written.
An application imbedded time stamp will not affect the order of the log blocks in the log stream. If an application needs to ensure that log blocks are received into the log stream in the order written, IBM® recommends that applications serialize on the log stream before they write to it.
Applications can optionally request that IXGWRITE return the time stamp that system logger generates for a log block using the TIMESTAMP parameter.