Service Broker Internal Activation Poisoning - Where? - sql-server

Question

I am experiencing poison messages and I am not sure why.
My broker setup looks like this:
CREATE MESSAGE TYPE
[//DB/Schema/RequestMessage]
VALIDATION = WELL_FORMED_XML;
CREATE MESSAGE TYPE
[//DB/Schema/ReplyMessage]
VALIDATION = WELL_FORMED_XML;
CREATE CONTRACT [//DB/Schema/Contract](
[//DB/Schema/RequestMessage] SENT BY INITIATOR,
[//DB/Schema/ReplyMessage] SENT BY TARGET
)
CREATE QUEUE Schema.TargetQueue
CREATE SERVICE [//DB/Schema/TargetService]
ON QUEUE Schema.TargetQueue (
[//DB/Schema/Method3Contract]
)
CREATE QUEUE Schema.InitiatorQueue
CREATE SERVICE [//DB/Schema/InitiatorService]
ON QUEUE Schema.InitiatorQueue
Then I have my internal activation procedure:
CREATE PROCEDURE Schema.Import
AS
DECLARE #RequestHandle UNIQUEIDENTIFIER;
DECLARE #RequestMessage VARCHAR(8);
DECLARE #RequestMessageName sysname;
WHILE (1=1)
BEGIN
BEGIN TRANSACTION;
WAITFOR (
RECEIVE TOP(1)
#RequestHandle = conversation_handle,
#RequestMessage = message_body,
#RequestMessageName = message_type_name
FROM
Schema.TargetQueue
), TIMEOUT 5000;
IF (##ROWCOUNT = 0)
BEGIN
COMMIT TRANSACTION;
BREAK;
END
EXEC Schema.ImportStep1 #ID = #RequestMessage;
--EXEC Schema.ImportStep2 #ID = #RequestMessage;
END CONVERSATION #RequestHandle;
COMMIT TRANSACTION;
END
My activation is enabled by:
ALTER QUEUE Schema.TargetQueue
WITH
STATUS = ON,
ACTIVATION
( STATUS = ON,
PROCEDURE_NAME = Schema.Import,
MAX_QUEUE_READERS = 10,
EXECUTE AS SELF
)
I initiate this process with this stored procedure
CREATE PROCEDURE Schema.ImportStart
AS
BEGIN
DECLARE #ID VARCHAR(8);
DECLARE Cursor CURSOR FOR
SELECT ID FROM OtherDatabase.OtherSchema.ImportTable
EXCEPT
SELECT ID FROM Table
OPEN Cursor;
FETCH NEXT FROM Cursor INTO #ID;
WHILE ##FETCH_STATUS = 0
BEGIN
DECLARE #InitiateHandle UNIQUEIDENTIFIER;
DECLARE #RequestMessage VARCHAR(8);
BEGIN TRANSACTION;
BEGIN DIALOG
#InitiateHandle
FROM SERVICE
[//DB/Schema/InitiatorService]
TO SERVICE
N'//DB/Schema/TargetService'
ON CONTRACT
[//DB/Schema/Contract]
WITH
ENCRYPTION = OFF;
SELECT #RequestMessage = #ID;
SEND ON CONVERSATION
#InitiateHandle
MESSAGE TYPE
[//DB/Schema/RequestMessage]
(#RequestMessage);
COMMIT TRANSACTION;
FETCH NEXT FROM Cursor INTO #ID;
END
CLOSE Cursor;
DEALLOCATE Cursor;
END
So how this should work is:
I execute ImportStart
A message for each ID gets generated
Internal activation makes Import steps execute
Instead, I get poison messaging and the queue becomes disabled.
If however,
I I set Schema.TargetQue Activation to OFF
EXEC schema.ImportStart
EXEC schema.Import manually
It works fine.
Any insights anyone?

Answer 1

Well:
Your message types are defined as well_formed_xml, yet you send varchar(8) as a message body. Does it really work?
You use [//DB/Schema/Method3Contract] for the target queue, but do not define it. A misspelling, most likely.
You specify EXECUTE AS SELF in the queue activation. BOL says some mystical thing about this case:
SELF
Specifies that the stored procedure executes as the current user. (The database principal executing this ALTER QUEUE statement.)
I'm not really sure I understand the quoted statement, because it apparently contradicts with your experience. If it would be your user account, everything should have been fine, because you seem to have all permissions necessary to do the job.
So, just in case - who is the owner of the Schema schema? What permissions does this principal possess? And, if it's not you, who executes the alter queue statement (and why)?
Without access to logs, it's significantly more difficult to diagnose the problem, but I would start with creating a new user account with permissions identical to yours, setting it the owner of the Schema schema and then slowly working it down, revoking unnecessary permissions until it breaks. Assuming, of course, it will work at all.