TMF Glossary (G06.26+)

TMF Glossary
HP NonStop TMF Glossary—522415-003
Glossary-19
two-phase commit
two-phase commit. An industry-standard series of operations performed when an
ENDTRANSACTION statement is executed to commit a transaction. In the first phase,
the before-images and after-images for the transaction are written to the audit trail on
disk. In the second phase, locks held by the transaction are released.
U
undo-needed file. An audited file that contains changes that must be undone because of
one or more aborted transactions. Such files cannot be opened. They are automatically
recovered by the volume recovery process when that is possible; otherwise, you must
use the file recovery process to recover them.
unilateral abort. An abort caused by a participant in a transaction that is not yet in the
prepared state.
unresolved transaction. A distributed transaction that TMF cannot determine whether to
commit or abort. This transaction was in the prepared state when the communication
lines between the home and remote nodes failed, and remains in this state until either
the connection between the nodes is reestablished or the transaction is resolved by an
operator. Sometimes, unresolved transactions are also called in-doubt transactions.
user-defined transaction. A TMF transaction initiated by an application either in a program
unit or in a requester on whose behalf the program unit performs database operations.
Contrast with system-defined transaction.
V
volatile resource manager. A resource manager that represents data that does not need to
be recovered after a failure, such as objects in main memory, user processes
maintaining transactional variables, window managers, and servers maintaining
context during transaction execution.
volume recovery. The automatic process of recovering database files to their most recent
consistent state if they become inconsistent because of a disk volume or system
failure. To recover the files, TMF redoes committed transactions to ensure that they are
reflected correctly in the database, and then backs out all transactions that were
incomplete at the time of the interruption.
Z
ZTMFCONF subvolume. The subvolume that contains TMF configuration information and
the TMF catalog files. See configuration subvolume.
ZTMFAT subvolume. The subvolume on which TMF audit trails are stored. Only TMF can
rename, purge, or alter files in this subvolume.