How can I have a gap in the SQL Server Job Agent history for a job? I have a job (Update Tickets) scheduled in Job Agent with a single schedule of "Occurs every day every 30 minute(s) between 12:00:00 AM and 11:59:59 PM. Schedule will be used starting on 11/4/2013." When I use Log File Viewer to see the history for this job, I see no entries for a 2.5 hour period yesterday. Other jobs on the same server ran during the time this one job had the gap in executions.



The job does an INSERT from SELECT from an OpenQuery from a Linked Server. If there was a network or other issue that prevented the connection to the data source from succeeding, I would still expect to see a job failure message in the log, but I see no entries for it at all. Neither the SQL Server log, SQL Server Agent log, nor the Windows System or Application logs show anything relevant during the time of the gap. 

What are the possible causes of this?

Thanks,

Mark
Check the duration of the job prior to the first slot it "missed." Typically job history won't have gaps unless:


The previous instance of the job is still running - SQL Server knows not to start two copies of the same job concurrently, so it just skips that slot.
The job was disabled during that time.
Someone deleted the history from msdb.dbo.sysjobhistory.