S.B. Navathe, K. Karlapalem, and M. Ra. A mixed fragmentation methodology for initial distributed database design. In Technical Report. CIS Dept, Univ. of Florida, Gainesville, FL, 1990. TR 90-17.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....the application programs to different portions of data (file of records) They define applications in terms of boolean predicates and use access pattern information to achieve the design. Predicates are collected into sets of minterms which form the horizontal fragments. Navathe, Karlapalem and Ra [14] define a scheme for simultaneously applying the horizontal and vertical fragmentation algorithms on a relation to produce a grid. A technique similar to the vertical fragmentation schemes discussed in Navathe et al. 13, 15] is used to produce horizontal fragments. Ozsu and Valduriez [17] define ....

....methods that access a set of objects and instance variables Further, they argue that a precise definition of the processing semantics of the applications is necessary. They do not present solutions for horizontally fragmenting class objects but argue that techniques used by Navathe et al. [14] for fragmenting relations could be applied. 2 The DOBS model A distributed object based system is a collection of local object bases distributed at different sites, interconnected by a network. We assume the database management system (DBMS) is distributed and the objects making up the object ....

S.B. Navathe, K. Karlapalem, and M. Ra. A mixed fragmentation methodology for initial distributed database design. In Technical Report. CIS Dept, Univ. of Florida, Gainesville, FL, 1990. TR 90-17.

....any two records belonging to a minterm fragment is the same. A complete set of predicates is minimal if and only if all its elements are relevant. Further, implications exist between boolean expressions of simple predicates which eliminate meaningless minterms. Navathe, Karlapalem and Ra [27] define a scheme for simultaneously applying the horizontal and vertical fragmentation algorithms on a relation to produce a grid. A technique similar to the vertical fragmentation schemes discussed in [26, 28] is used to produce horizontal fragments. They consider transactions with high access ....

....methods that access a set of objects and instance variables 3 Further, they argue that a precise definition of the processing semantics of the applications is necessary. They do not present solutions for horizontally fragmenting class objects but argue that techniques used by Navathe et al. [27] for horizontal fragmentation could be applied. 2.4.2 Vertical Fragmentation Karlapalem et al. 15] define issues involved in distribution design for an object oriented database system. They identify two types of methods simple and complex methods. Their first model consists of simple ....

S.B. Navathe, K. Karlapalem, and M. Ra. A mixed fragmentation methodology for initial distributed database design. In Technical Report. CIS Dept, Univ. of Florida, Gainesville, FL, 1990. TR 90-17.

....To fragment a class, it is possible to use two basic techniques: vertical fragmentation and horizontal fragmentation. It is also possible to perform mixed (or hybrid) fragmentation on a class, combining both techniques. The importance of mixed fragmentation was already detected in Navathe et al. [13], zsu and Valduriez [14] and was addressed in Baiao et al. 1] In the object model, vertical fragmentation breaks the class logical structure (its attributes and methods) and distributes them across the fragments, which will logically contain the same objects, but with different structures. On ....

.... (search over class extensions) and navigation (traversals) 3 Comparing related work in the area Many researchers addressed the distribution design in the relational model, including Ceri and Navathe [6] Navathe and Ra [12] zsu and Valduriez [14] Molina and Hsu [11] and Navathe et al. [13]. In the object context, there are also many works evidencing the importance of the distribution design to improve performance of applications manipulating large volumes of data in object DBMS. Karlapalem et al. 9] describe different aspects of a distributed object DBMS that are critical to the ....

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Navathe, S., Karlapalem, K., Ra, M., "A Mixed Fragmentation Methodology for Initial Distributed Database Design", Journal of Computer and Software Eng. 3(4), 1995

.... Keywords: Object oriented databases, Horizontal fragmentation, Distribution, Performance analysis 1 Introduction The importance of fragmentation of database entities and subsequent allocation to distributed sites (relations or classes) have been argued by many works including [NR89, OV91, EB95, NKR95, BSS96, EB98] All distributed database design work so far in the literature are static because input to the design process, which include queries accessing database and their frequencies as well as the database schema, are obtained from an earlier full requirements analysis. The implication of ....

S.B. Navathe, K. Karlapalem, and M. Ra. A Mixed Fragmentation Methodology for Initial Distributed Database Design. Journal of Computer and Software Engineering, 3(4), June 1995.

....mixed fragmentation, as well as vertical and horizontal fragmentation. Through mixed fragmentation we may combine the advantages of reducing irrelevant data (vertical) with the enhancement on the degree of parallelism (horizontal) The importance of mixed fragmentation was already detected in [19] for the relational model. The analysis algorithm is implemented as a set of rules to decide the most adequate fragmentation technique to be applied in each class of the database schema, based on developed heuristics. We have presented an example of the proposed algorithm using the 007 benchmark ....

NAVATHE, S., KARLAPALEM, K., RA, M., 1995, "A Mixed Fragmentation Methodology for Initial Distributed Database Design", Journal of Computer and Software Engineering, vol. 3, n 4

.... to address the relationship between entities: primary horizontal fragmentation is applied on owner entities, while derived fragmentation is applied on member entities according to the owner fragmentation [2, 3] Many researchers have worked on distributed design in the relational model, including [2,4,5]. However, in the OO model, the fragmentation process is much more complex than in the relational case. Karlapalem et al. 1] describe the different aspects of a distributed OODBMS that are critical to the distributed design process, which are: the data model; method invocation; types of location ....

....Ck in Ch by its fragment that contains the relevant element for the derived fragmentation return Fv end Figure 4 Algorithm for the vertical fragmentation phase: defining vertical fragments of classes in Cv fragments of the classes indicated in the first step. The algorithm presented in [5] was used for this step, with some adaptations needed to consider both attributes and methods of a class. Figure 4 shows this algorithm. 3.4 Step 3: Horizontal fragmentation The third step of our strategy defines the horizontal fragments of the classes indicated in the first step. Both function ....

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Navathe, S. et. al, "A Mixed Fragmentation Methodology for Initial Distributed Database Design", Journal of Computer and Software Engineering, vol. 3(4), 1995

.... [14] Navathe and Ra [16] and Shin and Irani [3] Ceri, Negri and Pelagatti [2] show that the main optimization parameter needed for horizontal fragmentation is the number of accesses performed by the application programs to different portions of data (file of records) Navathe, Karlapalem and Ra [15] define a scheme for simultaneously applying the horizontal and vertical fragmentation algorithms on a relation to produce a grid. A technique similar to the vertical fragmentation schemes discussed in Navathe et al. 14, 16] is used to produce horizontal fragments. Ozsu and Valduriez [18] define ....

....1 They take complex methods as being synonymous with an application. Horizontal Fragmentation of Classes in a DOBS 4 processing semantics of the applications is necessary. They do not present solutions for horizontally fragmenting class objects but argue that techniques used by Navathe et al. [15] for horizontal fragmentation could be applied. Vertical Fragmentation (objects) Karlapalem et al. 8] define issues involved in distribution design for an object oriented database system. They identify two types of methods simple and complex methods. Their first model consists of simple ....

S.B. Navathe, K. Karlapalem, and M. Ra. A mixed fragmentation methodology for initial distributed database design. In Technical Report. CIS Dept, Univ. of Florida, Gainesville, FL, 1990. TR 90-17.

....ones proposed in the literature, will end up having unsuitable fragmentation for classes having different access patterns, incurring in bad performance. 3 Related Work Many researchers have worked on distributed design in the relational model, including ZSU and VALDURIEZ [16] and NAVATHE et al.[15]. In the same way, there are many works demonstrating the importance of the Distributed Design of Object Oriented Databases (DDOODB) to improve performance of non conventional applications that manipulate large volumes of data [3,9,10,17] However, despite the recent proposals for the DDOODB in ....

Navathe, S., Karlapalem, K., Ra, M., 1995, "A Mixed Fragmentation Methodology for Initial Distributed Database Design", Journal of Computer and Software Engineering, vol. 3, n° 4

....to synchronize with the server at different frequencies. How access frequencies can affect these heuristics should be studied. The effectiveness of the allocation of fragments is also limited by the fragmentation scheme. Applicability and consequences of methods such as vertical and horizontal [NKR96] CNW93] must be studied. The heuristics given in this paper aim at optimizing upstream costs. We are also exploring ways of improving downstream costs as well. Currently, a popular method of update transmission is message based, using store and forward techniques to offload data dissemination. ....

S.B. Navathe, K. Karlapalem, and M.Y. Ra. A mixed fragmentation methodology for the initial distributed database design. Journal of Computers and Software Engineering, 3(4), 1996.

....data relevant to each client. We want to design groups that reduce the scalability limiting redundancy created by the overlap between client data interests in the client centric approach. The creation of a grouping relates to fragmentation design and allocation in traditional distributed databases[24, 26] so we shall draw on many of the ideas in that body of work. 2.1 Fragmentation Design Typical ISDB systems allow administrators to define vertical and horizontal partitions of tables of a relational DBMS to which clients subscribe. Sybase describes this process as employing data qualifications ....

....this process as employing data qualifications similar to the where clause in a SQL select command, making fine granularity replication possible. 13] Hence, given the transactions performed by each client, we can generate an initial fragmentation, and tune it with techniques described in [4, 23, 24]. As described in [27] fine grained units of updates (i.e. small fragments) improve the performance of client server synchronization, because they are more likely to contain little or no superfluous information. Although [27] suggests that tuple sized fragments are optimal for client ....

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S. B. Navathe, K. Karlapalem, and M. Y. Ra. A mixed fragmentation methodology for the initial distributed database design. Journal of Computers and Software Engineering, 3(4), 1996.

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