SQL Server does not catch link server timeout error - sql-server

Question

I wrote a procedure that calls another procedure through link server, it has try catch block and catch block works very well in case of most of the errors, for example when I want to "insert a NULL value to a not null able column" catch block is executed successfully and log error result to my table,but when it comes to link server timeout, catch block is not working, I don't know where I missed things up that caused this issue.
You can take a look at my procedure
AS
BEGIN
BEGIN TRY
BEGIN TRANSACTION
DECLARE #BeforeCall DATETIME,#AfterCall DATETIME,#DiffSec BIGINT,#CycleId BIGINT
DECLARE #TBL TABLE(Date INT,Time INT,Branch INT,Amount BIGINT)
----------------Get Last CycleId------------------------------------------
SELECT TOP 1 #CycleId=CycleId FROM dbo.BranchesResetDate_History
ORDER BY CycleId DESC
SET #CycleId=ISNULL(#CycleId,0)+1;
------------------------------------------------------------------
-----------------Get Reset Date--------------------------------------------
SET #BeforeCall=GETDATE()
INSERT INTO #TBL
(
Date,
Time,
Amount,
Branch
)
EXEC [AB_TO_FK].[xxxx].dbo.GetResetDate
SET #AfterCall=GETDATE()
SET #DiffSec=DATEDIFF(SECOND,#BeforeCall,#AfterCall)
-------------------------------------------------------------------
--------------------Log Execute Result To History------------------
INSERT INTO dbo.BranchesResetDate_History (Date,Time,Branch,Amount,InsertionDateTime,SecondsElapsed,CycleId)
SELECT Date,Time,Branch,Amount,dbo.DateTimeMDToSHD(GETDATE()),#DiffSec,#CycleId
FROM #TBL
--------------------------------------------------------------------
---------------------Insert Result To Main Table--------------------
INSERT INTO dbo.BranchesResetDate
(
ResetDate,
ResetTime,
BranchCode,
Amount,
InsertionDateTime
)
SELECT Date,
Time,
Branch,
Amount,
dbo.DateTimeMDToSHD(GETDATE())
FROM #TBL
-------------------------------------------------------------------
-------------Delete Duplicate Records------------------------------
DELETE res FROM (
SELECT id,ROW_NUMBER() OVER(PARTITION BY BranchCode,ResetDate,ResetTime,Amount ORDER BY ResetTime)rn FROM dbo.BranchesResetDate
) res WHERE res.rn>1
-------------------------------------------------------------------
COMMIT TRANSACTION;
END TRY
BEGIN CATCH
IF ##TRANCOUNT>0
ROLLBACK TRANSACTION;
------------------------Log Exception------------------------------
INSERT INTO dbo.Proc_Exception (ErrorNumber,ErrorSeverity,ErrorState,ErrorProcedure,ErrorLine,ErrorMessage,DateTime)
SELECT ERROR_NUMBER(),
ERROR_SEVERITY(),
ERROR_STATE(),
ERROR_PROCEDURE(),
ERROR_LINE(),
ERROR_MESSAGE(),
dbo.DateTimeMDToSHD(GETDATE())
-------------------------------------------------------------------
END CATCH
END
GO
When it reaches to line below
EXEC [AB_TO_FK].[xxxx].dbo.GetResetDate
In case of timeout error, catch block does not executed and I just get this error
OLE DB provider "SQLNCLI11" for linked server "AB_TO_FK" returned message "Query timeout expired

Answer 1

Timeout is always caused by the client (here the server with the linked server definition), which cancels the running query by sending a TDS Attention event. The error message you see is generated locally, and (for reasons lost to history) does not have a high-enough severity to trigger a CATCH block or flip ##error.
The recommended solution is to prevent the linked server timeout.
Either by extending it, eg setting the remote query timeout to 0 (infinite wait), by using this code:
sp_configure 'remote query timeout', 0
go
reconfigure with override
go
as per this support article, or by causing the remote call to fail with a trappable error instead of timeout. EG you can SET LOCK TIMEOUT in the procedure or in the batch sent to the remote server before running the procedure.
If the remote procedure succeeds it should return 0. If it fails it should return some non-zero value, and if it's canceled due to a timeout it will return null. So you can check like this:
declare #r int
execute #r = [AB_TO_FK].[xxxx].dbo.GetResetDate
if (#r is null or #r <> 0)
begin
throw 51000, 'Linked Server Procedure failed. Possible timeout.', 1;
end
And you can capture both the stored procedure return code and a resultset. And if it's supposed to output a resultset, you can also determine if it failed by checking the table after the execute. EG
declare #t table (rc int)
declare #r int = -1
insert into #t(id)
execute #r = Loopback.tempdb.dbo.bar
if (#r is null or #r <> 0 or 0 = (select count(*) from #t) )
begin
throw 51000, 'Linked Server Procedure failed. Possible timeout.', 1;
end