Checkdb error with SQL Graph EDGE constraint..

Question

With just the following basic graph setup, running on SQL Server 2019 CU 14 (and several earlier CUs on other test machines): I get a checkdb error 8992 on the sysmultiobjrefs for the constraint.

SELECT @@VERSION
GO
USE master
GO
DROP DATABASE identityHub
GO
CREATE DATABASE identityHub
GO
USE identityHub
GO

CREATE SCHEMA identityGraph
GO

CREATE TABLE [IdentityGraph].[ToastContact](
[ToastContactId] [uniqueidentifier] NOT NULL
)
AS NODE
GO

CREATE TABLE [IdentityGraph].[MarketingContact](
[MarketingContactId] [int]
)

AS NODE
GO

CREATE TABLE [IdentityGraph].[MarketingLink]
AS EDGE
GO

ALTER TABLE [IdentityGraph].[MarketingLink] ADD CONSTRAINT [ECNodes$LinkedTo$MarketingContact] CONNECTION (IdentityGraph.[MarketingContact] To IdentityGraph.[ToastContact])
GO

Version Output:

Microsoft SQL Server 2019 (RTM-CU14) (KB5007182) - 15.0.4188.2 (X64)
Nov 3 2021 19:19:51
Copyright (C) 2019 Microsoft Corporation
Developer Edition (64-bit) on Windows Server 2016 Standard 10.0 <X64> (Build 14393: ) (Hypervisor)
``----------

When I run DBCC CHECKDB::

Error MessageText

---

8992 Check Catalog Msg 3851, State 1: An invalid row (class=28,depid=629577281,depsubid=1,indepid=581577110,indepsubid=1) was found in the system table sys.sysmultiobjrefs (class=28).
8992 Check Catalog Msg 3851, State 1: An invalid row (class=28,depid=629577281,depsubid=1,indepid=597577167,indepsubid=0) was found in the system table sys.sysmultiobjrefs (class=28).
8992 Check Catalog Msg 3858, State 1: The attribute (type=EC) of row (object_id=629577281) in sys.objects has an invalid value.

Bug?

Answer 1

Yes, I got the same error as you Louis. I guess you know the procedures. File a bug on the feedback site, if you can live with it. Open a support case if it is a blocking issue.

Answer 2

Thank you for your patience. The issue has been addressed and a fix is included in Cumulative Update 16 (CU16) for SQL Server 2019: https://support.microsoft.com/en-us/topic/kb5011644-cumulative-update-16-for-sql-server-2019-74377be1-4340-4445-93a7-ff843d346896#bkmk_14558430

After installation of CU16, there are no additional steps needed. Subsequent execution of DBCC CHECKCATALOG or DBCC CHECKDB will no longer report those incorrect errors.

If there are any further questions, please let us know.

Answer 3

Sorry for the trouble. Unfortunately, this is a known issue with CHECKDB and graph edge constraints, which leads to the errors being (incorrectly) raised. There is no "real" corruption in this case. A fix for this issue will be available in an upcoming cumulative update. I will update this thread when we have released the fix publicly.

Answer 4

Run checkdb on your model database. When you create a new database, it copies the model db to the new db.

See:
https://learn.microsoft.com/en-us/sql/relational-databases/databases/rebuild-system-databases?view=sql-server-ver15#RebuildProcedure