KB3211338 - FIX: An assert error occurs when you insert data into a memory-optimized table that contains a clustered columnstore index in SQL Server 2016

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Consider the following scenario when you use SQL Server 2016:

  • You create a clustered columnstore index on a memory-optimized table that contains a column of data type string (for example, nchar or nvarchar).

  • The data length of the column isĀ 32 bytes (for example, nchar(16) or nvarchar(16)).

  • The data in the column is unique or almost unique, and the data size is 32 bytes.

In this scenario, when you insert data into this table, you may receive the following assert error in the SQL Server error log:

vldPageCount <= SegmentsTableRow::MaxSerializedPages


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

Note After you install the update, you must set trace flag 9968 to enable the fix. To set trace flag 9968, see the Trace Flags (Transact-SQL) topic on the Microsoft Developer Network (MSDN) website.

Each new build for SQL Server 2016 contains all the hotfixes and security fixes that were included in the previous build. We recommend that you install the latest cumulative updates for SQL Server:

Latest cumulative update for SQL Server 2016


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


Learn about the terminology Microsoft uses to describe software updates.

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