FIX: Automatic update of incremental statistics is delayed in SQL Server 2014, 2016 and 2017

Applies to: SQL Server 2017 DeveloperSQL Server 2017 EnterpriseSQL Server 2017 Enterprise Core More

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:

       Cumulative Update 3 for SQL Server 2017

Service pack information for SQL Server

This issue is fixed in the following service packs for SQL Server:

       Service Pack 2 for SQL Server 2016

       Service Pack 3 for SQL Server 2014

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 terminology that Microsoft uses to describe software updates.