Distributed Database

ABSTRACT In this paper, we introduce and experimentally assess ClustCube, an innovative OLAP-based framework for clustering and mining complex database objects extracted from distributed database settings by means of complex SQL statements involving multiple JOIN queries across (distributed) relational tables. To this end, ClustCube puts together conventional clustering techniques and well-consolidated OLAP methodologies in order to achieve higher expressive power and mining effectiveness over traditional methodologies for mining tuple-oriented information. A relevant challenge in our research is represented by the issue of efficiently computing ClustCube cubes, enriched by the respective cuboid lattices, which may represent a critical bottleneck for the proposed ClustCube framework. To face-off this drawback, we propose a collection of algorithms that implement an innovative distributive approach taking advantages from both the structured nature of complex database objects within cuboids and the distributive nature of clustering across hierarchical domains, like those defined by conventional OLAP schemas.

In designing a heterogeneous database systems, one of the main technical challenges is developing techniques for ensuring global commit. That is, guaranteeing that a transaction spanning multiple individual database management systems (DBMSs) either commits at all the participating DBMSs or at none of them. Previous work in this area typically assumes that the participating DBMSs do not provide a mechanism for interacting with their commit facilities. While this is true in many cases, in practice there are systems which support a programmatic interface to their commit protocols. We refer to database systems offering such facilities asexternalized commit DBMSs.

The advanced access to different databases by means of one single interface has become a critical and important requirement for most archives and content providers. This paper describes an application case for a system architecture capable of retrieving large and diversified contents by means of innovative networking and search engines based on the Qimera platform. The system is supposed to

Abstract—When a database is shared by many users, updates to the database schema are almost always prohibited because there is a risk of making existing application programs obsolete when they run against the modified schema. This paper addresses the problem by integrating ...

Systematics, the scientific discipline that deals with listing, describing, naming, classifying and identifying living organisms is at a turning point. Expertise becomes extremely rare. For future biodiversity studies relying on species identification, environmental technicians will only be left with monographic descriptions and collections in museums. With the emergence of knowledge management on the Internet, it is possible to enhance the

Several approaches for the full replication of data in distributed databases [1] have been studied. One of the preferred techniques is the eager update everywhere based on the total-order multicast delivery service [2], where the most outstanding varieties are: certification-based and weak-voting [1]. Under this approach, the execution flow of a transaction can be split into two different main phases:

We present the motivation, use-case and requirements of a clini- cal case research network that would allow biomedical research- ers to perform retrospective analysis on de-identified clinical cases joined across a large scale (nationwide) distributed net- work. Based on semi-join adaptive plans for fusion-queries, in this paper we discuss how joining can be done in a way that protects the

We present the motivation, use-case and requirements of a clini- cal case research network that would allow biomedical research- ers to perform retrospective analysis on de-identified clinical cases joined across a large scale (nationwide) distributed net- work. Based on semi-join adaptive plans for fusion-queries, in this paper we discuss how joining can be done in a way that protects the

Abstract A read-only transaction or query is a transaction which does not modify any data. Read-only transactions could be processed with general transaction processing algorithms, but in many cases it is more efficient to process read-only transactions with special algorithms which take advantage of the knowledge that the transaction only reads. This paper defines the various consistency and currency requirements that read-only transactions may have. The processing of the different classes of read-only transactions in ...

Data replication is a key issue in a Data Grid and can be managed in different ways and at different levels of granularity: for example, at the file level or object level. In the High Energy Physics community, Data Grids are being developed to support the distributed analysis of experimental data. We have produced a prototype data replication tool, the Grid Data Mirroring Package (GDMP) that is in production use in one physics experiment, with middleware provided by the Globus Toolkit used for authentication, data movement, and ...