When you run the DBCC CHECKDB/CHECKTABLE command, the data purity checks can cause the command to unexpectedly run a long time. This problem occurs for the DBCC CHECKDB/CHECKTABLE command in the following circumstances:

  • Assume that you have database or table that contains SQL CLR User-Defined type (UDT) data in Microsoft SQL Server 2012. SQL Server is not reusing the internal blob memory correctly during the validation of the SQL CLR UDT.

  • The granted memory for the DBCC operations (checktable or checkdb per table) is estimated incorrectly on large-memory servers.

This problem can cause excessive memory and CPU consumption.


Service pack information

To resolve this issue, obtain the following Service Pack for SQL Server.

For more information about SQL Server 2012 Service Pack 3 (SP3) and SQL Server 2014 Service Pack 1 (SP1), see bugs that are fixed in SQL Server 2012 Service Pack 3 and bugs that are fixed in SQL Server 2014 Service Pack 1.

Cumulative update information

The issue was first fixed in the following cumulative update of 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. We recommend that you download and install the latest cumulative updates for SQL Server:


For more information about DBCC operations, see the following blog posts on MSDN:


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

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