PURPOSE: The QUEUE TRACE option controls whether the DS requests being generated by the user’s program are tracked and the corresponding messages displaying at the terminal.
SYNTAX
{ENABLE; DISABLE} QUEUE TRACE [IF; UNLESS clause]
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ENABLE |
turns on trace mode for DS’s for which there are queues. It also causes messages to display at the terminal each time the user’s program generates a request for the DS. |
|
DISABLE |
turns off the tracing facility and message displaying. This is the default state. |
|
IF; UNLESS |
specifies a condition for the option to be enabled or disabled. |
Example
*ENABLE QUEUE TRACE...*DISABLE QUEUE TRACENOTES: The messages generated by ENABLE QUEUE TRACE are as follows:
(1) Queuing {N}
(2) Queue request blocked - resource not available
(3) Queue request unblocked - request satisfied
(4) Dequeuing {N}
(5) Queue request aborted
(6) Queue request timed out
Key: {N} = Data Set name
Message (1) is displayed when a program that specifies the Concurrent Queued or Exclusive Queued environment requests a DS and the DS is opened and queued.
Message (2) is displayed immediately after Message (1) if the request for a DS cannot be granted at present because the DS is being used.
Message (3) is displayed when the user’s request for a DS is granted.
Message (4) is displayed when the user’s program releases a DS.
Message (5) is displayed when the user aborts out of a program by typing a Control-C while queued for a DS or record.
Message (6) is displayed when the waiting time for a busy DS or record exceeds @DS_WAIT seconds or @RECORD_WAIT seconds, respectively. If the current program is queued for a DS, it will abort; if it is queued for a record, a time interrupt will occur and @AUX will be set to "BUSY."
The messages provided by the QUEUE TRACE option are a subset of those provided by the QUEUE DEBUG option (described earlier). QUEUE TRACE traces only DS access attempts, whereas QUEUE DEBUG traces both DS and record access attempts.
SEE ALSO: QUEUE DEBUG (earlier in this chapter).