Release 11.9.x introduced the new command line utility optdiag. optdiag enables you to read, write and simulate statistics. Working directly with the statistics as stored in sysstatistics and systabstats is difficult because of their datatypes, optdiag makes it practical to read and modify statistics. Also, optdiag allows you to test performance based on simulated statistics.
optdiag output is essential when analyzing optimizer-related problems. It contains all the information about the data set that you need.
See the Performance and Tuning Guide for information on optdiag.