Using global trace output

Trace output is based on the parameters specified for the -START TRACE(GLOBAL) command. Each record identifies one or more significant Db2 events.

Interpreting trace record formats
The destination of global trace records (specified with the DEST keyword of the -START TRACE command) affects their contents and, therefore, their interpretation. Data sent to the resident trace table (RES) contains only addresses and contents of registers. Data sent to GTF (Generalized Trace Facility) and SMF (System Management Facility) also may contain control blocks and storage areas.
When to use the Db2 trace table
Global trace data sent to the resident trace table usually appears at the end of the formatted section of a Db2-issued SVC dump.
Interpreting the formatted global trace table
The formatted Db2 trace tables are printed in time sequence from the oldest to the most current. To begin an analysis, review the most current entries (these appear at the end). Continue analyzing the information by scanning backward.
Interpreting the unformatted global trace table
The formatted trace table contains information copied from the unformatted resident trace table, which is always included in the non-summary section of the dump data set.
Distributed data facility global trace
The distributed data facility contains a serviceability trace.
Correlating the Db2 trace with the z/OS trace
To associate entries in the Db2 trace table with entries in the z/OS® trace table, compare time of day for both entries.
Interpreting GTF and SMF global trace records
Db2 global trace data written to GTF has a GTF ID of X'0FB9' and an FID of X'00'. Records longer than the 256-byte limit of GTF are spanned by Db2.
Using the statistics trace for distributed diagnosis
The statistics class 4 can be used to diagnose Distributed Relational Database Architecture™ (DRDA) and distributed two-phase commit exception conditions.
Using the performance trace for diagnosis
While the performance trace is primarily a tuning aid, it can sometimes be useful for diagnosis because degraded performance can also indicate a Db2 problem, one for which you would specify the PERFM keyword in building a keyword string to describe the problem.
Trace field descriptions
You can find descriptions of trace records in the IFCID flat file (DSNWMSGS).

Parent topic: Printing and analyzing global traces