I have a deadlock report that tells me that there was a conflict involving

waitresource="KEY: 9:72057632651542528 (543066506c7c)"

and I can see this:

<keylock hobtid="72057632651542528" dbid="9" objectname="MyDatabase.MySchema.MyTable" indexname="MyPrimaryKeyIndex" id="locka8c6f4100" mode="X" associatedObjectId="72057632651542528">

within the <resource-list> element.

I want to be able to find the actual value for the key (id = 12345, for example). What SQL statement would I need to use to obtain that information?

  • This question, and this answer, is worth 5k votes. Not the difference between inner and left join. Commented Jul 21, 2022 at 9:24

4 Answers 4


The answers from @Kin, @AaronBertrand, and @DBAFromTheCold are great and were very helpful. One important piece of info I found during testing that the other answers left out is that you need to use the index that is returned from sys.partitions for the given HOBT_ID when looking up the %%lockres%% (via an index query hint). This index is not always the PK or clustered index.

For example:

--Sometimes this does not return the correct results.
SELECT lockResKey = %%lockres%% ,* 
FROM [MyDB].[dbo].[myTable]  
WHERE %%lockres%% = @lockres
--But if you add the index query hint, it does return the correct results
SELECT lockResKey = %%lockres%% ,* 
FROM [MyDB].[dbo].[myTable] WITH(NOLOCK INDEX([IX_MyTable_NonClustered_index]))  
WHERE %%lockres%% = @lockres

Here is an example script modified using pieces from each of these answers.

declare @keyValue varchar(256);
SET @keyValue = 'KEY: 5:72057598157127680 (92d211c2a131)' --Output from deadlock graph: process-list/process[waitresource] -- CHANGE HERE !
--Should not have to change anything below this line: 
declare @lockres nvarchar(255), @hobbitID bigint, @dbid int, @databaseName sysname;
--PARSE @keyValue parts:
SELECT @dbid = LTRIM(SUBSTRING(@keyValue, CHARINDEX(':', @keyValue) + 1, CHARINDEX(':', @keyValue, CHARINDEX(':', @keyValue) + 1) - (CHARINDEX(':', @keyValue) + 1) ));
SELECT @hobbitID = convert(bigint, RTRIM(SUBSTRING(@keyValue, CHARINDEX(':', @keyValue, CHARINDEX(':', @keyValue) + 1) + 1, CHARINDEX('(', @keyValue) - CHARINDEX(':', @keyValue, CHARINDEX(':', @keyValue) + 1) - 1)));
SELECT @lockRes = RTRIM(SUBSTRING(@keyValue, CHARINDEX('(', @keyValue) + 0, CHARINDEX(')', @keyValue) - CHARINDEX('(', @keyValue) + 1));
--Validate DB name prior to running dynamic SQL
SELECT @databaseName = db_name(@dbid);  
IF not exists(select * from sys.databases d where d.name = @databaseName)
    RAISERROR(N'Database %s was not found.', 16, 1, @databaseName);

declare @objectName sysname, @indexName sysname, @schemaName sysname;
declare @ObjectLookupSQL as nvarchar(max) = '
SELECT @objectName = o.name, @indexName = i.name, @schemaName = OBJECT_SCHEMA_NAME(p.object_id, @dbid)
FROM ' + quotename(@databaseName) + '.sys.partitions p
JOIN ' + quotename(@databaseName) + '.sys.indexes i ON p.index_id = i.index_id AND p.[object_id] = i.[object_id]
JOIN ' + quotename(@databaseName)+ '.sys.objects o on o.object_id = i.object_id
WHERE hobt_id = @hobbitID'
--print @ObjectLookupSQL
--Get object and index names
exec sp_executesql @ObjectLookupSQL
    ,N'@dbid int, @hobbitID bigint, @objectName sysname OUTPUT, @indexName sysname OUTPUT, @schemaName sysname OUTPUT'
    ,@dbid = @dbid
    ,@hobbitID = @hobbitID
    ,@objectName = @objectName output
    ,@indexName = @indexName output
    ,@schemaName = @schemaName output

DECLARE @fullObjectName nvarchar(512) = quotename(@databaseName) + '.' + quotename(@schemaName) + '.' + quotename(@objectName);
SELECT fullObjectName = @fullObjectName, lockIndex = @indexName, lockRes_key = @lockres, hobt_id = @hobbitID, waitresource_keyValue = @keyValue;

--Validate object name prior to running dynamic SQL
IF OBJECT_iD( @fullObjectName) IS NULL 
    RAISERROR(N'The object "%s" was not found.',16,1,@fullObjectName);

--Get the row that was blocked
--NOTE: we use the NOLOCK hint to avoid locking the table when searching by %%lockres%%, which might generate table scans.
DECLARE @finalResult nvarchar(max) = N'SELECT lockResKey = %%lockres%% ,* 
FROM ' + @fullObjectName
+ ISNULL(' WITH(NOLOCK INDEX(' + QUOTENAME(@indexName) + ')) ', '')  
+ ' WHERE %%lockres%% = @lockres'

--print @finalresult
EXEC sp_executesql @finalResult, N'@lockres nvarchar(255)', @lockres = @lockres;

You have the hobt_id so the following query will identify the table:-

SELECT o.name
FROM sys.partitions p
INNER JOIN sys.objects o ON p.object_id = o.object_id
WHERE p.hobt_id = 72057632651542528

From that you can then run the following statement to identify the row in the table (if it still exists):-

WHERE %%LOCKRES%% = '(543066506c7c)'

Be careful with the above statement however, it will scan the target table so run in READ UNCOMMITTED and monitor your server.

Here's an article by Grant Fritchey about %%LOCKRES%% - http://www.scarydba.com/2010/03/18/undocumented-virtual-column-lockres/

And here's an article from my own blog about using %%LOCKRES%% to identify rows from an extended event:- https://dbafromthecold.wordpress.com/2015/02/24/identifying-blocking-via-extended-events/


The is a supplement to the answers already posted by DBAFromTheCold and Aaron Bertrand.

Microsoft has still left %%lockres%% as undocumented feature.

Below is the script that will help you :

declare @databaseName varchar(100) = 'yourdatabaseName' --CHANGE HERE !
declare @keyValue varchar(100) = 'KEY: 9:72057632651542528 (543066506c7c)' --Output from deadlock graph -- CHANGE HERE !
declare @lockres varchar(100)
declare @hobbitID bigint

select @hobbitID = convert(bigint, RTRIM(SUBSTRING(@keyValue, CHARINDEX(':', @keyValue, CHARINDEX(':', @keyValue) + 1) + 1, CHARINDEX('(', @keyValue) - CHARINDEX(':', @keyValue, CHARINDEX(':', @keyValue) + 1) - 1)))

select @lockRes = RTRIM(SUBSTRING(@keyValue, CHARINDEX('(', @keyValue) + 1, CHARINDEX(')', @keyValue) - CHARINDEX('(', @keyValue) - 1))

declare @objectName sysname
declare @ObjectLookupSQL as nvarchar(max) = '
SELECT @objectName = o.name
FROM ' + quotename(@databaseName) + '.sys.partitions p
JOIN ' + quotename(@databaseName) + '.sys.indexes i ON p.index_id = i.index_id AND p.[object_id] = i.[object_id]
join ' + quotename(@databaseName)+ '.sys.objects o on o.object_id = i.object_id
WHERE hobt_id = ' + convert(nvarchar(50), @hobbitID) + ''

--print @ObjectLookupSQL
exec sp_executesql @ObjectLookupSQL
    ,N'@objectName sysname OUTPUT'
    ,@objectName = @objectName output

--print @objectName

declare @finalResult nvarchar(max) = N'select %%lockres%% ,* 
from ' + quotename(@databaseName) + '.dbo.' + @objectName + '
where %%lockres%% = ''(' + @lockRes + ')''
--print @finalresult
exec sp_executesql @finalResult

Also refer to this excellent blog post on : The Curious Case of the Dubious Deadlock and the Not So Logical Lock


Sorry, was already working on this answer and about to post when the other appeared. Adding as community wiki only because it's a slightly different approach and adds a bit of other info.

The 543066506c7c is essentially a hash of the primary key, and you can retrieve that row (and potentially any rows with a hash collision) using this dynamic SQL:

-- Given: KEY: 9:72057632651542528 (543066506c7c)
-- and object = MyDatabase.MySchema.MyTable

  @hobt BIGINT = 72057632651542528,
  @db SYSNAME = DB_NAME(9),
  @res VARCHAR(255) = '(543066506c7c)';

DECLARE @exec NVARCHAR(MAX) = QUOTENAME(@db) + N'.sys.sp_executesql';

  FROM MySchema.MyTable WHERE %%LOCKRES%% = @res;';

EXEC @exec @sql, N'@res VARCHAR(255)', @res;

You can do this without dynamic SQL, of course, but this gives you a nice template for a snippet or stored procedure where you can just plug the values in, if this is something you troubleshoot a lot. (You could also parameterize the table name, and you could also build in parsing of the KEY: string to determine everything for you dynamically, but I thought that might be out of scope for this post.)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.