TMF Operations and Recovery Guide (G06.26+)

Occasional Operations

HP NonStop TMF Operations and Recovery Guide—522417-003

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Changing the Autoabort Configuration

The TMF autoabort function automatically aborts transactions if they run longer than a

set amount of time. This feature is useful in an online transaction processing

environment where the transactions are usually short, and long-running transactions

are assumed to be “runaways.” Since long-running transactions are identified and

automatically aborted, you can turn off the autoabort function if you know that there are

going to be many long-running transactions.

The time limit used to identify long-running transactions is known as the autoabort

threshold. This threshold specifies the length of time that a transaction can run before

TMF automatically aborts it. By default, the autoabort threshold is two hours.

Autoabort Threshold

Increasing the autoabort threshold means that transactions can run longer before TMF

automatically aborts them. Consider increasing this threshold if you notice that TMF is

frequently aborting transactions and the active capacity of the audit trail is well below

the overflow threshold. If the audit trail is near its overflow threshold, increase the size

of the audit trail before you increase the autoabort threshold. TMF performance is

better when TMF is not frequently interrupted to back out transactions.

Decreasing the autoabort threshold means that TMF aborts transactions sooner.

Consider decreasing this threshold when transaction durations are normally shorter

than the autoabort threshold, or when you want runaway transactions to be aborted

sooner.

Setting the autoabort threshold to a non-zero value means that TMF automatically

backs out transactions that exceed the autoabort threshold. By default, the autoabort

threshold is two hours.

Setting the autoabort threshold to 0 turns the autoabort feature off, so that transactions

can run until completion, regardless of the time required. Do not turn off the autoabort

feature unless you are certain that there is enough space in the audit trail to

accommodate the audit-trail files that may be pinned for an extended time while

transactions complete.

Note. If transactions run too long, the audit trail can reach its overflow threshold and,

eventually, can reach its begin-transaction-disable threshold.