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While looking for a reason behind slowness of the database server I accidentaly came across Preemptive_Xe_Dispatcher wait.

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Could you please suggest how this type of wait should be troubleshooted? Information coming from google is very generic and disn't provide any practical solutions.

  • Are you heavily relying on XE audit features ? Is there a XE session running doing audit task. Other question are you facing performance issue ? Why do you think this wait is problem – Shanky Dec 8 '16 at 13:04
  • Only system_health is session is running. Yes, there is performance impact. We are facing slowness and deadlocks despite having abandance of resourses and hardly any users in the system. This wait was one of a few unusual things I found. I am now eliminating potential problems one by one, but I don't know how to approach this wait. – QWE Dec 8 '16 at 13:46
  • Deadlock should not be because of system health session running or because of the wait type. I believe the issue lies either with queries running or app design. What is output of select @@version – Shanky Dec 8 '16 at 13:51
  • I dont really believe that there is any direct connection between this wait type and deadlocks. I am just interested in this wait type because I never came across it and I am not sure if it can impact performance. I would like to investigate this, but I am not sure how to approach it. – QWE Dec 8 '16 at 14:17
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    I would ignore this wait and focus on CXPACKET. If you've already got MAXDOP and cost threshold for parallelism set to recommended values, you need to dig into the queries. Run sp_BlitzCache @SortOrder = 'Avg CPU' and start with those queries for your troubleshooting. – Tara Kizer Dec 8 '16 at 16:59

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