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Description of the QDBSRVxx System Jobs
Document Description:
At each IPL, numerous system jobs that start with the name of QDBSRV are
activated. The following is an overview description of the functions
performed by these jobs:
QDBSRVXR - This job maintains each of the system cross-reference files in
QSYS with the exception of the field cross-reference file. These files
contain cross-reference information about data base files and SQL
information across the system. The files all begin with the name of QADB in
library QSYS. The primary file that must be maintained is QADBXREF. This
file is the file cross-reference file. It contains a record for each
physical and logical file on the system. Create, change, or delete of any
file will cause the QDBSRVXR job to become active.
QDBSRVXR2 - This job maintains the only system cross-reference file that is
not maintained by QDBSRVXR, the field cross-reference file. This file is
QADBIFLD in library QSYS. This file contains a record for every field of
every physical and logical file on the system. Create, change, or delete of
any file causes the QDBSRVXR job to become active.
QDBSRV01 - This job can be viewed as the database maintenance task
dispatcher. Typically, it will be the most active immediately following the
restore of a library that contains database files. It's function includes:
o Signalling to the SMAPP (System Managed Access Path Protection) LIC
tasks that new access paths have been restored. SMAPP will then
determine whether these access paths need to be protected.
o Sending data queue entries to the QDBSRVXR job of new database files
that were restored.
o Sending data queue entries to the QDBSRVXR2 job of new database file
fields that were restored.
o Preparing the list of access paths that are required to be rebuilt
because the access paths were not restored. This is the list that is
viewed via the EDTRBDAP command.
QDBSRV02-03 - These two jobs perform access path maintenance on system
files. Typically, the jobs are inactive.
QDBSRV04-05 - These two jobs perform access path maintenance on user data
files. Typically, these jobs are inactive. However, in certain cases, these
jobs will be active performing access path rebuilds. The access paths that
are being maintained can be viewed via the EDTRBDAP command. Some reasons
why these jobs could be active are:
o Restore of database files that were not saved with access paths.
o Restore of logical files that are in the same library as the physical
file they are based upon.
o Cancelling of a RGZPFM command while in process.
o Invalidation of an index due to damage found upon it.
QDBSRV06-09 - On systems with additional processors, additional system jobs
are started to allow for additional concurrent access path rebuilds. These
jobs perform the same tasks as QDBSRV04-05. |
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发表于 2005-12-07 19:42
发表于 2005-12-08 12:17
