StorageTek Lifecycle Director DB2 Manager 312564001 User Manual

Page of 189
 
70 
DB2 Manager User Guide 
 StorageTek 
Proprietary 
Offset Length Format Description 
60 
Bin 
Record number within object containing 
stored/retrieved row 
62 
Bin 
Number of records containing 
stored/retrieved row 
64 8 char 
Requester’s 
jobname 
72 
char 
Requester’s userid.   
80 
char 
Identifier of system on which request 
originated 
84 12  - 
Reserved 
 
 
 
Operational considerations 
This section discusses miscellaneous topics relating to the operation of the 
DB2 Manager control region and its environment. This includes a discussion 
of performance considerations for retrieval of migrated rows from an Archive 
Manager database using DB2 Manager. 
Use of the MAXTRDR parameter 
The MAXTRDR parameter is used to limit the number of tape cartridge drives 
that DB2 Manager will allocate concurrently for performing simultaneous 
access to multiple tape volumes in response to migrated row retrieval 
requests. It is intended to enable users to prevent DB2 Manager from 
depleting the number of available cartridge drives on a system to the extent 
that other work will be unable to complete. 
Once at the MAXTRDR limit, DB2 Manager will reject any other request 
which would require an extra tape drive in order for it to be satisfied, with a 
‘resource unavailable’ condition, or optionally queue the request internally if a 
non-zero value has been specified for the TAPEWAIT parameter in the 
TAPECNTL parameter library member.   In this latter case DB2 Manager will 
retry the request at 1-second intervals until a tape drive becomes available or 
until the TAPEWAIT interval is exceeded.  
Rejection of a request due to the MAXTRDR value having been reached or 
due to the TAPEWAIT interval having been exceeded will generate an SQL –
652 error and reason code (in field SQLERRD(6) in the SQLCA) of X’1015’. 
The value chosen for MAXTRDR should ensure that occurrence of this 
condition is minimized, while still allowing other work on the system to 
continue without delay. If necessary, the value of MAXTRDR may be varied 
during the day to correspond to variations in the system workload.