11.1 How Merged Logs are Created

In order to create a merged log the application retrieves the first log record from each source log and compares them. The log record that has the smallest value in the merge column (e.g. the oldest timestamp) is the next record to be copied to the merged log. For more information about the merge column can be found in Loading, Merging, Browsing and Closing Logs. A copied record is not considered anymore in the next comparisons but its succeeding log record. The merging algorithm terminates after all records have been copied to the merged log.

It might occur that the timestamps of log records within a log are not in the correct chronological order as shown in the following example:

2011-10-10, 15:20, Log record 1
2011-10-10, 13:00, Log record 2
2011-10-10, 13:01, Log record 3
2011-10-10, 15:22, Log record 4

Log records are not in the correct chronological order

This might happen when someone changed the system clock between the creation of these log records: It can be assumed that “Log record 2” and “Log record 3” were created after “Log record 1” although they have an older timestamp because they were written to the log after “Log record 1” and logs are usually created from top to bottom.

However, the application can be configured to sort the log records within a log by their merge column before merging them with other log records or to leave them in the order they occur. Open the Tools menu and select Options. Expand the Performance category. If you set OmitMergeColumnSort to FALSE the merge column of a log will be sorted before merging, if you set this field to TRUE sorting will be omitted.