What does the QDBSRVnn job do?

From the IBM Web site, here is a description of a couple of types of QDBSRVxx jobs.

QDBSRVxx - Database Server (high priority)
QDBS###Vxx - Database Server (high priority) for Independent Disk Pool Group ###

These jobs perform journal and commitment control maintenance for the system and are considered quick or short running work. QDBS###Vxx was created in V5R3.

QDBSRVxx - Database Server (low priority)
QDBS###Vxx - Database Server (low priority) for Independent Disk Pool Group ###

These jobs perform access path maintenance on user database files. Typically these jobs are inactive; however, in certain cases they may activate to perform access path rebuilds. The access paths that are being maintained can be viewed using the EDTRBDAP command. Some reasons why these jobs could be active are:

Restore of database files that were not saved with access paths

Restore of logical files without the physical file they are based upon

Canceling of a RGZPFM command while in process

Invalidation of an index due to damage found upon it

Post OS/400 installation activity to complete cross-reference or other IBM DB2 upgrade activity

Constraint Verification. The EDTCPCST command shows constraints that are awaiting completion of such verification.

QDBS###Vxx was created in V5R3.