StorageTek 312564001 manual Tapecntl: Maxqlen, Tapecntl: Retaintape

scheduler subtask introduces some processing overhead, so care should be taken to avoid over-allocation of this setting.

This setting may be varied during DB2 Manager operation via the 'SET MAXSCHED’ operator command.

If this parameter is omitted, a default value of MAXSCHED=4 will be used.

TAPECNTL: MAXQLEN

MAXQLEN = nnn

Requirement: Optional

Default: 4

Validation: nnn = 1-3 digit numeric value in range 1 - 256

Use: The MAXQLEN parameter specifies the maximum number of retrieval requests which may be simultaneously queued for any single tape-reader subtask in the control region.

Notes: DB2 Manager will queue requests for retrieval from an Archive Manager tape volume which is already being processed, on a 'first-in first-out' basis, up to the maximum level specified in this parameter.

If TAPEWAIT=0 is specified, requests which cause this maximum to be exceeded will receive a “resource busy” condition from DB2 Manager - an SQL error code of –652 will be returned to the calling application and field SQLERRD(6) in the SQLCA will contain the hexadecimal value x’0A’.

Non-zero values of TAPEWAIT will cause requests which encounter this condition to be held internally for processing until a tape drive becomes available, or until the time limit specified in the TAPEWAIT parameter is exceeded, at which point a “resource busy” condition will be returned to the calling application, as above.

This setting may be varied during DB2 Manager operation via the 'SET MAXQLEN' operator command.

If this parameter is omitted, a default value of MAXQLEN=4 will be used.

TAPECNTL: RETAINTAPE

RETAINTAPE = nnnn

40	DB2 Manager User Guide
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