Methods materialisation in object-oriented databases: implementation and experimental evaluation

• Autorzy: Jezierski J. , Masewicz M. , Wrembel R.
• Języki publikacji: EN

Abstrakty

EN

A method can be a very complex program, whose computation may last long. Therefore the efficient execution of a method has a great impact on a query response time. Optimising access to data returned by methods is difficult as methods are written in a high-level programming languages. Moreover, estimating a method's execution cost is another serious problem because of the complexity of a method's code. In this paper we propose a framework for the materialisation of method results in object-oriented databases. A materialisation of a method consists in computing the result of a method once, store it persistently in a database and then use the persistent value when the method is invoked. However, the result of a materialised method has to be kept up to date after updating objects used to compute the value of this method. To this end, we use additional data structures representing links between materialised methods and objects used to compute these methods. When such an object is updated, the system uses these data structures in order to invalidate outdated results. In our approach, the materialisation of method m results also in the materialisation of intermediate results of methods called from m. We call this technique hierarchical materialisation. When an object used to materialise the result of in is updated, then in is invalidated. Next invocation of in for the same object, results in the recomputation of in by using unaffected intermediate materialised results of methods called from in. Thus, the recomputation time overhead is reduced. The hierarchical materialisation technique was implemented and evaluated in a prototype based on the FcistObjects t7 object-oriented database.

Słowa kluczowe

EN

object-oriented database

PL

baza danych obiektowa

• Wydawca: Wydawnictwo Politechniki Poznańskiej
• Czasopismo: Foundations of Computing and Decision Sciences
• Rocznik: 2004
• Tom: Vol. 29, No. 3
• Strony: 171--192
• Opis fizyczny: Bibliogr. 24 poz.

Twórcy

autor

Jezierski J.

• Poznań University of Technology, Institute of Computing Science, Piotrowo 3a 60-965 Poznań, Poland

autor

Masewicz M.

• Poznań University of Technology, Institute of Computing Science, Piotrowo 3a 60-965 Poznań, Poland

autor

Wrembel R.

• Poznań University of Technology, Institute of Computing Science, Piotrowo 3a 60-965 Poznań, Poland

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