Use the generalized trace facility (GTF) to obtain diagnostic information
during the processing of VSAM Record Management (R/M). If GTF is active
and TRACE= (record management tracing) is specified
in your DD statement, VSAM GTF trace records, X'FF5', are
written to the GTF data set.
Note: The speed at which trace data
is written
out to GTF has been increased and this can lead to an increase in
the number of lost event records (trace record that can not be written
out due to the GTF performance). The number of lost event records
will increase, especially when the program is running under the multi-thread
environment. Therefore, it is recommended that you adjust the GTF
parameters when starting GTF before tracing. Adjustments such as increasing
the GTF buffer size, increasing amount of virtual storage that GTF
will use to collect trace data, and using VSAM linear data set as
the target data set will help to reduce the number of lost event records.
Refer to
z/OS MVS Diagnosis: Tools and Service Aids for
information on how to customize GTF
parameters.