XCOMU0602E Unable to QUEUE: Cannot Create Data File or Queue is Full

Products

XCOM Data Transport XCOM Data Transport - Windows XCOM Data Transport - Linux PC XCOM Data Transport - z/OS

Issue/Introduction

When the remote partner is Linux or UNIX, the message is XCOMU0602E Unable to QUEUE: Cannot Create Data File or Queue is Full

When the remote partner is Windows, the message is XCOMN0602E Unable to QUEUE: Cannot Create Data File or Queue is Full

The queue is designed to keep track of all incoming and outgoing transfers. Each transfer in the queue requires 512 bytes of shared memory. Each transfer is supplied a unique TID, or Transaction Identifier. All trace information associated with a transfer is identified by the TID and is available for the length of time that the transfer is in the queue. A brief history of every transfer is also written in the log.

Environment

Release: XCOM Data Transport
Component: Windows, Linux, UNIX

Cause

This message generally means that the queue is full for XCOM for Windows, UNIX or Linux.

Resolution

To resolve XCOMU0602E Unable to QUEUE: Cannot Create Data File or Queue is Full messages:

NOTE: Do this on the partner (destination) server.

Although this is not the most likely cause, check the xcom.tid file which is under the $XCOM_HOME/config directory (%XCOM_HOME%\Config for Windows). This contains the number of the next transfer ID number. Check this first because it is the easiest and quickest thing to check and correct. The xcom.tid file should have the next TID number. The number should be in a 6-digit format. If it is 0 or blank or not a number, delete the current xcom.tid file. (You may also put the next 6 digit transfer id number.) Stop and start xcomd.
If the TID file looks fine, increase the value for the parameter MAX_QUEUE_ENTRIES and/or decrease the value for EXPIRATION_TIME in the xcom.glb. This allows more transfers to be stored and processed in the Queue at any point in time. Stop and start xcomd to reload the new parameter values.
The values set for the EXPIRATION_TIME and MAX_QUEUE_ENTRIES GLB parameters depend on the maximum number of transfers that could be present in the queue at any one given time. NOTE: Transfers are not removed from the queue until the time specified in the EXPIRATION_TIME parameter passes.
For example, if there are 100 transfers at 6 pm and another 100 ten minutes later an EXPIRATION_TIME larger than 600 (10 Minutes) will require you to have a parameter setting of at least MAX_QUEUE_ENTRIES=200.
Or if you set the EXPIRATION_TIME to less than 600 (10 Minutes) then the Queue size will be sufficient. It is a balance between both parameters and your workload.

Additional Information

XCOMU0602E

What value should be set for MAX_QUEUE_ENTRIES? This value is the maximum number of transfers that will be need to be held in the queue. This is not the maximum number of concurrent transfers, because transfers are held in the queue after they complete (either successfully or unsuccessfully) until EXPIRATION_TIME passes. At this point, XCOM deletes the queue entry and any associated trace files.

Clear the queue manually by typing xcomqm -R* on the command line. Any transfers waiting to start will need to be resubmitted if you do this.

Allow extra entries to account for times when a partner may be down and transfers are held in the queue waiting for the partner to become available again. Also the number of transfers does tend to increase over time, so this number should be reviewed on a regular basis. The value supplied can not exceed n, where n is the maximum shared memory segment divided by 512. This value is limited by the amount of shared memory that is available. As the number of transfers in the queue increases so does the amount of memory used by XCOM.

What value should I set for EXPIRATION_TIME? EXPIRATION_TIME is specified in seconds. Since this value represents the maximum time that the transfer will be held in the queue after execution, you need to consider why you need to retain a transfer after it is finished. One reason for retaining a TID is to access the associated trace information. There is also detailed information regarding each specific transfer accessible through the XCOMTOOL and the XCOMQAPI. If most of your transfers are handled automatically or at off-peak hours then this information may be extraneous because each transfer will have information regarding its status recorded in the log.

It is also important to realize that as this value is reduced, the associated TID's become free and therefore the same number of entries can handle more transfers. This is particularly true if EXPIRATION_TIME is reduced drastically and the transfers are sent in a steady continuous pattern. Reducing the EXPIRATION_TIME may be necessary if you need to dramatically increase the value of MAX_QUEUE_ENTRIES. If you do not need to access information about completed transfers in the queue, you may set EXPIRATION_TIME as low as 1, raising it temporarily if you need to troubleshoot. The transfer information will still be available in the xcom.log.

Why would I suddenly receive this error code? This can happen if your EXPIRATION_TIME is high, multiple local transfers are initiated and XCOM for UNIX or LINUX is receiving multiple transfers from one or many partners. Remember if EXPIRATION_TIME is high, transfers that have completed are still reserving TID's. If enough TID's are reserved at the time the new transfers are queued, then you may see this error condition. Another possibility would be multiple partners sending multiple transfers at the same time. This can occur if a partner system has been down for some time and now is sending an inordinate amount of transfers while it completes its backlog of work.

What other related conditions can occur? While there are other reasons for xcomd stopping, one cause can be a lack of resources or memory. Lack of resources can cause xcomd to time out. The value for MAX_QUEUE_ENTRIES correlates to how much shared memory XCOM expects to access. If while in the process of managing many transfers, a memory intense application starts, than XCOM may not have enough memory to continue.

What else could this message indicate?

Another cause could be the queue still being full. Delete any completed transfers from the queue and stop and start xcomd. If the problem persists, then you will need to clear all of the transfers from the queue, xcomqm -R*, and then delete the 000026.idx file, and recycle xcomd again. The 000026.idx file is an index file used internally by XCOM for queue maintenance.
Another possible cause for this error condition would be a remote system being down. If the partner system can not process any of the transfer requests, this could cause the queue to reach capacity prematurely. Check the value for Remote System Name on the pending transfers. A single partner or group of partners may not be accessible due to network conditions. To resolve this, increase the value for the parameter MAX_QUEUE_ENTRIES and/or decrease the value for EXPIRATION_TIME in the xcom.glb. Stop and start xcomd to reload the new parameter values.
The remote partner XCOM has not started correctly e.g. XCOMU0465E and XCOMU0466E when starting XCOM