APAR status
Closed as program error.
Error description
A WebSphere MQ Managed File Transfer Protocol Bridge Agent is acting as the destination agent for a managed transfer. While processing a transfer item within a managed transfer, the FTP Server the Protocol Bridge Agent is communicating with becomes slow to respond and is unable to accept file data for approximately 70 seconds. As a result of this, the Protocol Bridge Agent times out while trying to write the file data, and the destination file is not written to the file server. However, no errors are reported and the transfer item is marked as "Successful".
Local fix
Problem summary
**************************************************************** USERS AFFECTED: This issue affects users of: - The WebSphere MQ V7.5 Managed File Transfer component. - The WebSphere MQ V8.0 Managed File Transfer component. who are using the Protocol Bridge Agent to connect to a file server using either the FTP or FTPS protocol. Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: When a WebSphere MQ Managed File Transfer Protocol Bridge Agent has been configured to connect to a file server using either the FTP or FTPS protocols, it uses the Apache Commons Net library to handle all of the communication with the file server. If the Protocol Bridge Agent is acting as the Destination Agent for a managed transfer, the Apache Commons Net library will establish two connections to the file server: - A control connection. This is used to initiate file transfers, and monitor their state. - A data connection, which is used to send the file data to the file server. When the Protocol Bridge Agent processes a transfer item within a managed transfer, it passes the file data for that transfer item to the Apache Commons Net library. The library then writes the file data to the file server asynchronously. This means that after the Protocol Bridge Agent has passed all of the file data to the Apache Commons Net library, it has to wait for the library to write the file data to the file server before it can determine if the transfer item was successful or not. If the file server became unresponsive or unavailable in between the Protocol Bridge Agent passing the last bit of file data to the Apache Commons Net library, and before the library had confirmed that the file data had been successfully written to the file server, then the Apache Commons Net library would either report an exception, or return FTP reply code 425, back to the Protocol Bridge Agent.. The Protocol Bridge Agent received this exception or reply code and incorrectly assumed that it had already been handled. As a result of this, the exception or reply code was ignored and the transfer item that was being transferred when the file server became unresponsive or unavailable was marked as as being "Successful", even though the file was not successfully written by the file server.
Problem conclusion
The Protocol Bridge Agent has been updated so that if a file server becomes unresponsive or unavailable in between the Protocol Bridge Agent passing the last bit of file data to the Apache Commons Net library, and before the library confirming that the file data had been successfully written to the file server, the Protocol Bridge Agent will put the transfer into recovery. If the property: logTransferRecovery=true has been set on the Protocol Bridge Agent, then a message, similar to the ones shown below. will be written to the Agent's output0.log file: BFGTR0030E: A recoverable I/O error has occurred during a write operation. The agent will attempt to recover the file transfer. The transfer ID is: . The error message is: BFGBR0064W: The server has terminated the connection. Exception: Read timed out BFGTR0030E: A recoverable I/O error has occurred during a write operation. The agent will attempt to recover the file transfer. The transfer ID is: . The error message is: BFGBR0186W: The server has terminated the connection. The reply string sent back by the server was 'PB-CLOSE - aborted [ReplyString=425 Can't open data connection.] --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v7.5 7.5.0.6 v8.0 8.0.0.4 The latest available FTE maintenance can be obtained from 'Fix List for WebSphere MQ File Transfer Edition 7.0' http://www-01.ibm.com/support/docview.wss?uid=swg27015313 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
IT09538
Reported component name
WMQ MFT
Reported component ID
5724H7242
Reported release
750
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2015-06-18
Closed date
2015-08-28
Last modified date
2015-08-28
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
WMQ MFT
Fixed component ID
5724H7242
Applicable component levels
R750 PSY
UP
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Document Information
Modified date:
27 January 2022