Cart M. and Ferris J., "Integrating Concurrency Control into an Object-Oriented Database System", Proc. Int. Conf. EDBT, Venice, Italy, pp. 363-377, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and 6 reported in [Bernstein 87] The Lock Instance Graph (LIG) represents the same hierarchy instantiated on the actual data items stored in the database. In the ODMS context, MGL protocol has been realised in ORION, an ODMS that supports multiple inheritance [Garza 88] and proposed in 02 [Cart 90] The motivation for using the MGL protocol in an ODMS is that the object oriented data model provides a natural hierarchical organisation of data items in granules of different size: every object is a member of the set representing the extension of a class; a class can be a subclass of one or ....

Cart M. and Ferris J., "Integrating Concurrency Control into an Object-Oriented Database System", Proc. Int. Conf. EDBT, Venice, Italy, pp. 363-377, 1990.

....relation for internal nodes, i.e. for method executions. Two method invocations x and y on the same object commute if and only if the two possible sequential executions of x and y are indistinguishable for both x and y and for all possible sequences of methods that may be invoked subsequently [CF90, HW91, MRW 93] Table 4.1 illustrates the commutativity relationships between the methods of class object Item. The entry indicates that the relationship is undefined. It is not necessary to derive commutativity relationships for all pair of methods of an object. decrease percent( ....

....of object oriented databases that are considered in the design of our protocol. In general, in object oriented databases, the conflicts and commutativity relations between methods are defined on a per class basis. Methods on different objects are generally assumed to commute with each other [GK88, CF90, HH91, MRW 93] This approach is reasonable for object oriented databases with disjoint complex objects. However, in a system with referentially shared sub44 objects, the commutativity relation needs to be redefined even for methods that are executed on different objects. One approach could ....

[Article contains additional citation context not shown here]

M. Cart and J. Ferri'e. Integrating Concurrency Control into an ObjectOriented Database System. In Proceedings of the International Conference on Extending Data Base Technology, Springer-Verlag, LNCS 416, pages 363--376, 1990.

....those systems. Three such criteria are: 1) partition objects based on access patterns (e.g. 25] 29] 2) partition objects based on the unit of transfer between a server and a client (e.g. 16] and 3) partition objects to increase locking granularity and thereby decrease overhead (e.g. [8]) The previous discussion brings to light an important distinction between programming language systems and ODBMSs that makes the design of garbage collection algorithms for ODBMSs especially challenging. In programming language systems, designers of collection algorithms have complete control ....

M. Cart and J. Ferri, "Integrating Concurrency Control into an Object-Oriented Database System," Proc. Second Int'l Conf. Extending Database Technology, Springer-Verlag, Mar. 1989.

....be dealt with by the transaction manager. Our approach allows methods on encapsulated objects to in turn invoke methods on other objects. Our approach to deal with the resulting method invocation hierarchies is based on open nested transactions and the related work on multilevel transactions [BBG89, BSW88, CF90, LMWF92, Ma87, MGG86, MRKN92, RGN90, Wa84, Wei91, WS92]. However, the structure of multilevel transaction trees is constrained such that operations at the same level of the tree belong to the same system layer. This structural limitation is waived in the more general notion of open nested transactions. In this paper we have addressed the important ....

Cart, M., Ferrie, J., Integrating Concurrency Control into an Object-Oriented Database System, 2nd Int. Conf. on Extending Database Technology, Venice, 1990, Springer, LNCS 416

....the application semantics in the higher layers where it is defined. 13.5. 4 Object oriented Database Systems Transaction management in object oriented database systems (OODBMSs) poses two big challenges: dealing with general object graphs that allow referentially shared (sub ) objects (e.g. [BR88, CF90]) and exploiting the semantics of methods (e.g. RGN90, SZ89] The first issue is orthogonal to whether one uses flat or nested transactions; the second issue is obviously related to open nested transactions. By viewing the dynamic method invocation hierarchy of a user invoked method as an open ....

Cart, M., Ferrie, J. Integrating Concurrency Control into an Object-Oriented Database System. 2nd Int. Conf. on Extending Database Technology, Venice, 1990, Springer, LNCS 416.

....criterion. This protocol is extended for further concurrency in Section 5. We conclude with a discussion in Section 7. 2 Related Work In traditional databases, the most commonly adopted correctness criterion is serializability. Object oriented database systems such as ORION [GK88, Kim90] and O 2 [CF90, BDK92] ensure the serializable execution of transactions. Both of these database systems employ a locking protocol based on multigranularity locking [Gra78] Multigranularity locking was developed to reduce locking overhead by organizing the database in the form of a hierarchy, e.g. the ....

....than y itself. Ancestor relationship is defined analogously. Two method invocations x and y on the same object commute if and only if the two possible sequential executions of x and y are indistinguishable for both x and y and for all possible sequences of methods that may be invoked subsequently [CF90, HW91, MRW 93] Table 1 illustrates the commutativity relationships between the methods of class object Item (note that the entry indicates that the relationship is undefined) decrease percent( report price( change price( commute decrease percent( report price( ....

[Article contains additional citation context not shown here]

M. Cart and J. Ferri'e. Integrating Concurrency Control into an Object-Oriented Database System. In Proceedings of the International Conference on Extending Data Base Technology, Springer-Verlag, LNCS 416, pages 363--376, 1990.

....into those systems. Three of them are: 1) partition objects based on access patterns (e.g. 19, 22] 2) partition objects based on the unit of transfer between a server and a client (e.g. 11] and (3) partition objects to increase locking granularity and thereby decrease overhead (e.g. [6]) If the criterion used to partition the object space is essentially a given, then what is the crucial element in the design of an ODBMS garbage collection algorithm The answer is partition selection, the selection of which partition to examine for garbage during a particular collection. Since ....

M. Cart and J. Ferri'e. Integrating Concurrency Control into an Object-oriented Database System. In Proceedings of the Second International Conference on Extending Database Technology. Springer-Verlag, March 1989.

....those systems. Three of those criteria are: 1) partition objects based on access patterns (e.g. 24, 27] 2) partition objects based on the unit of transfer between a server and a client(e.g. 15] and (3) partition objects to increase locking granularity and thereby decrease overhead (e.g. [7]) We follow Yong, Naughton, and Yu in generically referring to ODBMS garbage collection algorithms that examine groups of objects independently of other groups as partitioned collection algorithms [31] The previous discussion points up a key distinction between programming language systems ....

M. Cart and J. Ferri'e. Integrating Concurrency Control into an Object-oriented Database System. In Proceedings of the Second International Conference on Extending Database Technology. Springer-Verlag, March 1989.

....as trees of operation invocations, with edges representing the caller callee relationship between transactions and operations at different levels. This model has also been considered for dealing with method invocation hierarchies in transaction management for object oriented database systems [CF90, HH88, MRKN92, Mu93]. The children of the transaction root can also be viewed as subtransactions; so we are actually using a nested transaction model. Subtransactions may be committed (i.e. their effects are made visible to other transactions) independently of the commit of the transaction root; hence the name open ....

Cart, M., Ferrié, J., Integrating Concurrency Control into an Object--Oriented Database System, 2nd International Conference on Extending Database Technology, Springer, 1990

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