Technical Blog Post
75 ways to demystify DB2 #45: Techtip : How to capture critical performance diagnostics information for DB2 BLU ( BLU aka CDE - Columnar Data Engine) environment
Users can use the DB2 Trace Facility (db2trc) in DB2 BLU ( BLU aka CDE - Columnar Data Engine) environment to collect the critical performance diagnostics information using new component, CDE_PERF_TRACE.
- To collect performance diagnostics, one should run:
db2trc on –m CDE_PERF_TRACE ... run workload ... db2trc dmp perftrc.dmp db2trc off db2trc fmt perftrc.dmp perftrc.fmt
- There were reports on "db2trc on –m CDE_PERF_TRACE" not working due to some yet unidentified environment problem.
Then one may use the equivalent command:
db2trc on -m "*.*.CDE_PERF_TRACE.*.*"
- To make "performance log" persistent, tracing to disk may be used:
db2trc on –m CDE_PERF_TRACE –f perftrc.dmp
- This approach addresses the issue of the infinitely growing performance.log file. “Circular buffer” is available even when tracing to a file:
db2trc on –m CDE_PERF_TRACE –f perftrc.dmp –l 1G
- The new CDE performance trace is dynamic and it's easy to turn on or off.
- The new CDE performance trace allows one to specify which records are of interest and only these records will be traced.
For example, in order to trace only SQL-- text and CDE Runtime Statistics, use:
db2trc on -m ibm_cde::services::perftraceRuntimeStats -f trc.dmp
- The new CDE performance trace allows to trace data only for the specific application (identified by application handle or application ID).