Symptoms
In Microsoft SQL Server 2014, 2016 and 2017, when incremental statistics are built on the top of partitioned tables, the sum of modification counts of all partitions is stored as the modification count of the root node. When the modification count of the root node exceeds a threshold, the auto update of statistics is triggered. However, if the modification count of any single partition does not exceed the local threshold, the statistics are not updated. Additionally, the modification count of the root node is reset to zero. This may cause delay in the auto update of incremental statistics.
Resolution
This issue is fixed by triggering the auto update of statistics when the modification count of any partition exceeds the local threshold. Therefore, when the auto update of statistics is triggered, the statistics are updated correctly.
A new trace flag (TF) 11024 is also introduced. When this trace flag is enabled, the modification count of the root node is kept as the sum of modification counts of all partitions.
This issue is fixed in the following cumulative update 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:
Service pack information for SQL Server
This issue is fixed in the following service packs for SQL Server:
Service packs are cumulative. Each new service pack contains all the fixes that are in previous service packs, together with any new fixes. Our recommendation is to apply the latest service pack and the latest cumulative update for that service pack. You do not have to install a previous service pack before you install the latest service pack. Use Table 1 in the following article for finding more information about the latest service pack and latest cumulative update.
How to determine the version, edition and update level of SQL Server and its components
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminologythat Microsoft uses to describe software updates.
