Order Preserving Repartition Streams Can Cause Extreme Performance Degradations - by Joe Obbish

Status : 

  Fixed<br /><br />
		This item has been fixed in the current or upcoming version of this product.<br /><br />
		A more detailed explanation for the resolution of this particular item may have been provided in the comments section.


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ID 3141119 Comments
Status Resolved Workarounds
Type Bug Repros 5
Opened 9/15/2017 12:08:57 PM
Access Restriction Public

Description

Queries with an order preserving repartition streams operator that access tables with the right data distribution can appear to hang.

Instead of running for seconds as expected they can run for hours.

During the long runtimes almost no CPU is used.
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Posted by Joe Obbish on 11/22/2017 at 5:46 PM
This appears to be fixed in SQL Server 2016 SP1 CU6: https://support.microsoft.com/en-us/help/4046858/fix-parallel-query-execution-plan-with-a-merge-join-slow-to-execute-in
Posted by Microsoft on 9/26/2017 at 10:28 AM
We confirm this is a problem in Microsoft SQL Server, and we will make an appropriate fix with upcoming regular updates. Thank you very much for reporting this issue to us, and helping to make Microsoft SQL Server better.