TMF Management Programming Manual (G06.26+)

Commands and Responses
HP NonStop TMF Management Programming Manual—522420-003
5-40
ALTER BEGINTRANS
ZTmpMemThresh
specifies the lower and upper limits of the percentage of CPU memory
allocated to the TMP’s extended segment at which TMF automatically disables
and reenables new transactions.
The first value is the lower limit. When the percent of CPU memory allocated
to the TMP’s extended segment falls below this value, new transactions are
reenabled. This value must be less than the second value. If this field is
ZTMF-VAL-ResetWord or ZTMF-VAL-ResetDblWord, the value is 90.
The second value is the upper limit. When the percent of CPU memory
allocated to the TMP’s extended segment exceeds this value, new transactions
are disabled. This value must be greater than the first value. If this field is
ZTMF-VAL-ResetWord or ZTMF-VAL-ResetDblWord, the value is 95.
To prevent transaction processing from constantly switching back and forth
between the enabled and disabled states, a recommended approach is to
allow an adequate range between the values of the two limits.
ZTransPerCpu
specifies the maximum number of transactions that can run in TMP and non-
TMP CPUs.
The first value specifies the number of new transactions that can be started
concurrently in CPUs where the TMP does not run. Valid values are in the
range from 1 to 1073741824.
The second value specifies the number of new transactions that can be started
concurrently in CPUs where the TMP does run. This value includes any
network transactions begun on a remote node that involve the home (local)
node. Valid values are in the range from 1 to 1073741824.
Both values must be set to a power of 2. If either value does not meet this
requirement, it is rounded up to the next-higher power of 2. As an example, if
you specify 1000 for either of these values, the subsystem sets the value
to 1024.
Changes to ZTransPerCpu take effect at the next START TMF command.
ZAutoAbort
specifies the maximum number of seconds that a transaction can remain active
before it is susceptible to being automatically aborted. The minimum value is
20 seconds, the maximum value is 21474836 seconds (approximately eight
months). For most applications in typical OLTP environments, values close to
60 seconds are probably appropriate. If ZAutoAbort has the value 0, the
automatic abort feature is turned off and there is no time limit.
If this field is ZTMF-VAL-ResetWord, the value is 7200 seconds (two hours).