QlikView 12 - Task randomly skipped trigger

[Bastien_Laugiero]

Tasks do not triggering when they should.

See Tasks and reloads do not trigger, are queued, or give wrong status for more details.

Environment:

QlikView 12.00
QlikView 12.10
QlikView 12.20 (November 2017) and up

To troubleshoot this issue you will need to first check the QlikView Distribution Server logs and particularly the log called root.txt

Looking into this log at the time the task was supposed to be triggered you may find an event similar to:  

0171113T072731.006+0100    Information    DistributeTask[69a4c453-d6cf-4468-b72d-7161c965cc10] ("TASK NAME"): TryQueue successful. Triggered by 'TaskCompletedTrigger'. Id:a0bb81c1-a493-4fcf-b884-93dbb54e6850. ExecID:c2e91617-8feb-4d5a-92b7-67a3b63e98c0
20171113T072731.068+0100    Information    TriggerState: Change State to Ignored. Task="TASK NAME", ExecId=c2e91617-8feb-4d5a-92b7-67a3b63e98c0. Trigger TaskCompletedTrigger ignored. No QlikView Engine was available after waiting for 45 minutes.
The first event mention that the task is queued and the second indicates a failure for this task with the following information No QlikView Engine was available after waiting for 45 minutes.

Looking at the time those event have been triggered at the same time meaning that the QlikView Distribution Service has never waited 45 minutes to get a QlikView Engine available.

To get more information about where the logs are stored you can check this article How To Collect QlikView Server Log Files

Resolution

This can possibly have two root causes.

Increase in disk requirement for QlikView 12.10 and above 

QlikView Server 12.10, 12.20, 12.30 and above, are all more write-intensive on disk. If disk write queues are too long, the result can be a previous task execution not having been correctly updated. This will lead to a timeout the next time this task is run. 

A way to mitigate this would be to review QlikView 12: Tasks are Not Triggering Correctly, Becoming Queued, Etc.

Specific defect, ID QV-14003

Fixed Version:

• QlikView November 2017 SR7 and newer

! Information provided on this defect is given as is at the time of documenting.  For up to date information, please review the most recent Release Notes, or contact support at support.qlik.com with the ID QV-14003 for reference.

Cause:

If not related to bug above, there might be several causes for this behavior and some are listed below: 

• Antivirus not configured to exclude the necessary files and folder. More information in this article QlikView Folder And Files To Exclude From Anti-Virus Scanning
• Performance on the machine hosting the disk. You can check this by running a performance monitor on the machine How to log CPU and memory with Microsoft Performance Monitor on a windows 2012 Server (PerfMon)
• I/O activity to intense on the disk. To check this you might need to involve your IT Team and also check this article How can I monitor I/O activity on a specific file or folder in Windows? See QlikView and its backend File Share System for details around the issue.