TMF Introduction (G06.26+)

TMF Overview
HP NonStop TMF Introduction—522414-002
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What Characterizes the TMF Environment?
What Characterizes the TMF Environment?
TMF works in the OLTP environment to protect transactions for business operations
and maintain the consistency of the database. In general, a transaction is a multistep
operation that changes the database. For example, a transaction for an airline
reservation could include the operations of adding the reservation to the airline
passenger list, issuing a ticket, and adding the ticket price to accounts receivable.
OLTP applications, in particular, are critical applications for businesses. These
applications require timely information that reflects the current state of the business.
The transactions and database must be protected because many users are accessing
the same database. TMF manages two major processing problems:
•
Database consistency
•
Transaction concurrency
TMF manages these problems regardless of the distribution of the data.
Distributed Data
Often OLTP applications must access data that resides in different computer systems
at customer sites, in different types of databases, or on different platforms. To access
data on other platforms, TMF can interoperate with foreign transaction managers and
resource managers through transaction gateways, which translate from one protocol to
another.
Database Distribution
Frequently, the databases in OLTP applications are distributed so that data resides
where it is most frequently used. This distribution contrasts with undistributed data that
resides at a central site.
A distributed database is illustrated in Figure 1-2
. Both manufacturing and sales
databases reside in Seoul and Chicago, and only sales databases reside in San
Francisco and London, where there are only sales offices. TMF is active at all sites, to
protect the transactions and the database.
Distribution refers either to the location of data or to the location of processes that
access the data. A distributed database resides on more than one node of a network;
nodes (computer systems) can be dispersed geographically. Distributed transactions
involve transaction manager activity on more than one node.
Transactions processed on two or more nodes by TMF are called homogeneous
distributed transactions. Transactions processed under the control of multiple
transaction managers (TMF on a NonStop server and one or more foreign transaction
managers on one or more other platforms) are called heterogeneous distributed
transactions.