APAR status
Closed as program error.
Error description
An IBM MQ Managed File Transfer agent is configured to run a SourceTransferStartExit at the start of every managed transfer. The design of the SourceTransferStartExit means that it only expects to be run once for each managed transfer. If the exit detects that it is has been run more than once for a managed transfer, the exit returns an ResultCode of CANCEL_TRANSFER. Very occasionally, a network issue occurs which prevents the agent from being able to connect to its agent queue manager while performing transfer negotiation. As a result, the agent puts the managed transfer onto its backlog. When the agent attempts to negotiate the managed transfer again at a later time, the SourceTransferStartExit is run again. This causes the exit to return a CANCEL_TRANSFER ResultCode, which results in the managed transfer being marked as "Failed".
Local fix
Problem summary
**************************************************************** USERS AFFECTED: This issue affects users of IBM MQ Managed File Transfer who have agents configured to run SourceTransferStartExits at the beginning of managed transfers. Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: When a source agent receives a managed transfer request, it performs the following steps: - Resolve the transfer item specification into a list of transfer items (files or messages) to transfer. - Run any SourceTransferStartExits. - Run any preSource programs or commands. - Contact the destination agent for the managed transfer, and perform the transfer negotiation. Now, if a source agent detected a network issue while attempting to contact the destination agent as part of the transfer negotiation, it would put the managed transfer onto its backlog so that the negotiation could be retried later. However, when the agent picked up the managed transfer from its backlog, it would incorrectly re-run any SourceTransferStartExits before performing the negotiation. Depending on the design of the SourceTransferStartExit, this could result in unexpected behaviour.
Problem conclusion
To resolve this issue, MQ Managed File Transfer has been updated so that source agents now use the source transfer start exit results for a managed transfer, contained within the agent's state store, when determining whether any SourceTransferStartExits have already been run for that managed transfer. The source transfer start exits results are persisted in the state store as soon as the SourceTransferStartExits have been run, and before the transfer negotiation step begins. This means that if the managed transfer encounters a network issue during transfer negotiation, and is put onto the agent's backlog, then when the agent processes the managed transfer again, it detects that the SourceTransferStartExits have already been run, and so won't run them again before retrying the negotiation. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v9.1 LTS 9.1.0.8 v9.2 LTS 9.2.0.2 v9.x CD 9.2.2 The latest available MQ maintenance can be obtained from 'WebSphere MQ Recommended Fixes' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037 If the maintenance level is not yet available information on its planned availability can be found in 'WebSphere MQ Planned Maintenance Release Dates' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
IT35398
Reported component name
IBM MQ MFT V9.1
Reported component ID
5724H7272
Reported release
910
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2021-01-04
Closed date
2021-01-22
Last modified date
2021-01-22
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
IBM MQ MFT V9.1
Fixed component ID
5724H7272
Applicable component levels
[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910"}]
Document Information
Modified date:
23 January 2021