When checkout subset from HE it consumes high CPU and takes a long time to complete. Similar symptoms occur for checkin of a subset containing many updates
Using a large model which contains most of the business logic and has many subsets.
For that large model a subset download/upload and even a HE generation takes more than 50% of CPU.
For smaller models a download/upload does not exceed 30% CPU.
The DB2 DBA team did not notice any abnormal behaviour or contention during download and only the one user was downloading at the time.
Release : 8.6
Gen Engineering provided these suggestions:
1. If not already running CEUCLEN and DB2 REORG on the recommended weekly basis please run both before running a DB2 RUNSTATS and BIND. The CEUCLEN will delete/cleanup "orphan objects" for any incomplete models and subsets.
If the performance issue is happening because of incomplete subsets, then the CEUCLEN may also take a long time in which case it is recommended to run the CEUCLEN job over the weekend.
More details here: Host Encyclopedia Administration > Maintaining the Host Encyclopedia
2. Run the DB2 RUNSTATS (CEJOB06) and BIND (CEJOB07A) - Configuring Host Encyclopedia and Host Construction > Configuration Variables
3. If the performance problem still exists then consider making performance improvements per Host Encyclopedia Administration > Performance Recommendations.
4. If the performance problem still exists after that run DB2 EXPLAIN to narrow down the problem.