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Archive for January, 2015

Solution : Suspect Database – SQL Server detected a DTC/KTM in-doubt transaction with UOW .Please resolve it following the guideline for Troubleshooting DTC Transactions.

Posted by blakhani on January 27, 2015


While testing application which uses distributed transaction, I caused a failure of SQL Server Database. When I performed failover I found that database didn’t recover and failed to come online. It was shown as “Suspect” in SQL Server Management Studio. I checked ERRORLOG and found below messages.

2015-01-22 22:50:33.570    spid15s    Recovery of database ‘MyBadDatabase’ (5) is 0% complete (approximately 24 seconds remain). Phase 1 of 3. This is an informational message only. No user action is required.
2015-01-22 22:50:33.990    spid15s    Recovery of database ‘MyBadDatabase’ (5) is 2% complete (approximately 24 seconds remain). Phase 1 of 3. This is an informational message only. No user action is required.
2015-01-22 22:50:34.080    spid15s    Recovery of database ‘MyBadDatabase’ (5) is 0% complete (approximately 130 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.
2015-01-22 22:50:34.180    spid15s    Recovery of database ‘MyBadDatabase’ (5) is 11% complete (approximately 5 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.
2015-01-22 22:50:35.480    spid15s    Recovery of database ‘MyBadDatabase’ (5) is 44% complete (approximately 2 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.
2015-01-22 22:50:37.720    spid15s    10704 transactions rolled forward in database ‘MyBadDatabase’ (5). This is an informational message only. No user action is required.
2015-01-22 22:50:37.820    spid7s    Attempting to initialize Microsoft Distributed Transaction Coordinator (MS DTC). This is an informational message only. No user action is required.
2015-01-22 22:50:37.850    spid15s    CHECKDB for database ‘MyBadDatabase’ finished without errors on 2012-01-08 23:41:18.113 (local time). This is an informational message only; no user action is required.
2015-01-22 22:50:38.870    spid7s    Attempting to recover in-doubt distributed transactions involving Microsoft Distributed Transaction Coordinator (MS DTC). This is an informational message only. No user action is required.
2015-01-22 22:52:22.990    spid7s    SQL Server detected a DTC/KTM in-doubt transaction with UOW  {6BAC37B8-6515-4FC1-972B-C059D1D5133E}.Please resolve it following the guideline for Troubleshooting DTC Transactions.
2015-01-22 22:52:22.990    spid7s    Error: 3437, Severity: 21, State: 3.
2015-01-22 22:52:22.990    spid7s    An error occurred while recovering database ‘MyBadDatabase’. Unable to connect to Microsoft Distributed Transaction Coordinator (MS DTC) to check the completion status of transaction (0:743395420). Fix MS DTC, and run recovery again.
2015-01-22 22:52:22.990    spid7s    Error: 3414, Severity: 21, State: 2.
2015-01-22 22:52:22.990    spid7s    An error occurred during recovery, preventing the database ‘MyBadDatabase’ (database ID 5) from restarting. Diagnose the recovery errors and fix them, or restore from a known good backup. If errors are not corrected or expected, contact Technical Support.

 

As we can see that database was trying to recover. Phase 2 of roll forward is complete and Phase 3 (Rollback phase) encountered an error. The error is cause due to the fact that my bad application uses MSDTC and I caused things to break in MSDTC itself. Ideal way to fix the problem would be to follow KB http://support.microsoft.com/default.aspx?scid=kb;EN-US;306366 (PRB: Errors 3437, 3414, and "Could Not Connect to DTC" Occur When You Start SQL Server)

In my case, I have restarted DTC and I was not able to find UOW anywhere which I need to kill. When I checked sys.dm_tran_locks for column request_owner_guid for any GUID that is non ZERO. But I didn’t find any non Zero (6BAC37B8-6515-4FC1-972B-C059D1D5133E). Here are the steps I did to fix my database.

sp_configure 'show advanced options', 1 
GO 
RECONFIGURE 
GO 
sp_configure 'in-doubt xact resolution', 2 --- presume abort 
GO 
RECONFIGURE 
GO 

Error log showed the change.

2015-01-23 00:45:53.850 spid86       Configuration option ‘in-doubt xact resolution’ changed from 0 to 2. Run the RECONFIGURE statement to install.

In your case, you need to check with application vendor/team to find what needs to be done with In-doubt transactions. Please use appropriate value (I have used 2) and then perform recovery of database.

dbcc dbrecover(MyBadDatabase)

 

Once above steps are performed, I was able to get database recovered. Here is the snippet from errorlog.

2015-01-23 00:46:10.090 spid57       Bypassing recovery for database ID 5. This is an informational message only. No user action is required.

2015-01-23 00:46:10.100 spid57       Starting up database ‘MyBadDatabase’.

2015-01-23 00:47:28.570 spid57       Recovery of database ‘MyBadDatabase’ (5) is 0% complete (approximately 130 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.

2015-01-23 00:47:28.670 spid57       Recovery of database ‘MyBadDatabase’ (5) is 1% complete (approximately 7 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.

2015-01-23 00:47:29.630 spid57       Recovery of database ‘MyBadDatabase’ (5) is 29% complete (approximately 2 seconds remain). Phase 2 of 3. This is an informational message only. No user action is required.

2015-01-23 00:47:34.800 spid57       1 transactions rolled back in database ‘MyBadDatabase’ (5). This is an informational message only. No user action is required. 2015-01-23 00:47:34.800 spid57       Recovery is writing a checkpoint in database ‘MyBadDatabase’ (5). This is an informational message only. No user action is required. 2015-01-23 00:47:34.820 spid57       Recovery completed for database MyBadDatabase (database ID 5) in 6 second(s) (analysis 20 ms, redo 3142 ms, undo 3056 ms.) This is an informational message only. No user action is required.

2015-01-23 00:47:34.860 spid57       CHECKDB for database ‘MyBadDatabase’ finished without errors on 2012-01-08 23:41:18.113 (local time). This is an informational message only; no user action is required.

Hopefully this would bring database online if it was caused due to DTC problem. There might be various causes for suspect database and this blog just covers one of them.

  • Cheers,
  • Balmukund Lakhani
  • Twitter @blakhani
  • Author: SQL Server 2012 AlwaysOnPaperback, Kindle
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