StorageTek 312564001 Operational considerations, Use of the MAXTRDR parameter, Offset, Length

Offset

60

62

64

72

80

84

Length

2

2

8

8

4

12

Format	Description
Bin	Record number within object containing
	stored/retrieved row
Bin	Number of records containing
	stored/retrieved row
char	Requester’s jobname
char	Requester’s userid.
char	Identifier of system on which request
	originated

-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.
70	DB2 Manager User Guide
	StorageTek Proprietary