|
|
|
A Multi-Level Transaction Approach to Federated DBMS Transaction Management
|
| Title |
A Multi-Level Transaction Approach to Federated DBMS Transaction Management |
| Author(s) |
H.-J. Schek, G. Weikum, W. Schaad |
| Type |
inproceedings |
| Booktitle |
Proc. of the First Int. Workshop on Inter- operability in Multidatabase Systems, (IMS'91)Kyoto |
| Organization |
Institute for Information Systems, ETH Zurich |
| Month |
April
|
| Year |
1991 |
|
Abstract
Transaction management in federated database management
systems (FDBMS) is compared with multi-level transaction
management. An FDBMS has global and local transaction
management and can therefore be viewed as a multi-level
system. Autonomous execution and commit of subtransactions
is a key feature in both FDBMS transactions and multi-level
transactions. Consequently, in both models some dependencies
of lower levels are propagated to the higher level in order
to give the global transaction manager enough knowledge
about lower-level dependencies. In order to cope properly
with local transactions, not present in multi-level
transaction models proposed so far, a dynamic conflict
relation between global subtransactions is introduced. By
exploiting the knowledge about the context of the conflicts
between global subtransactions, we derive a weaker form of
multi-level serializability that is equivalent to
quasi-serializability. Our approach is further extended to
exploit the semantics of the high-level operations that
correspond to global subtransactions, even in the presence
of local transactions. As a consequence, aborts of global
transactions must be implemented by compensating
subtransactions, and complete (multi-level) serializability
is required for the resulting executions. A locking
protocol is proposed that allows the coexistence of global
multi-level transactions and local transactions, and the
required cooperation by the underlying DBMSs is discussed.
|
!!! Dieses Dokument stammt aus dem
ETH Web-Archiv und wird nicht mehr gepflegt !!!
!!! This document is stored in the
ETH Web archive and is no longer maintained !!!