When you try to create a Columnstore Index on a table in Microsoft SQL Server 2016 or 2017, the request may fail after 25 seconds with memory time-out error 8645, depending on how many memory consuming queries are running concurrently and/or how much memory is available at the time of the request. The memory time-out error may occur even when you configure longer memory request time-out at an instance level or at a resource pool level.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


This issue is fixed in the following cumulative updates for SQL Server:

Note: Enable Trace Flag (TF) 11047 to enable this fix.

About cumulative updates for SQL Server:

Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:


To work around this issue, you can either increase the amount of memory in the resource pool where Columnstore Index build runs or reduce the number of concurrent memory consuming queries or you can do both.


Learn about the terminology that Microsoft uses to describe software updates.

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Thank you for your feedback!