Transcript Data Mining Engineering

Databases and the Grid
Peter Brezany
Institute für Scientific Computing
University of Vienna
P.Brezany
Institute for Scientific Computing – University of Vienna
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Introduction
• This lecture part outlines how databases can be integrated into the
Grid.
• Most existing and proposed applications are file-based.
• Consequently, there has been little work on how databases can be
made available on the Grid for access by distributed applications.
• If the Grid is to support a wider range of applications, then
database integration into the Grid will become important. E.g. many
applications in the life and earth sciences, and many business
applications are heavily dependent on databases.
• The database integration into the Grid is not possible just by
adopting or adapting the existing Grid services that handle files, as
databases offer much richer operations (e.g. queries and transactions), and there is much greater heterogeneity between different
database management systems than there is between different file
systems.
• There are major differences between database paradigms (e.g.
object and relational) – within one paradigm different database
products (e.g. Oracle and DB2) vary in their functionality and
interfaces.
P.Brezany
Institute for Scientific Computing – University of Vienna
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Introduction (2)
• Existing DB systems do not offer Grid integration.
They are however result of many hundreds of
person-years of effort that allows them to provide
a wide range of functionality, valuable programming
interfaces and tools, and important properties such
as security, performance and dependability.
• Because the above attributes will be required by
Grid applications, scientists strongly believe that
building new Grid-enabled database management
systems (DBMSs) from scratch is both unrealistic
and a waste of effort.
• Instead we must consider how to integrate existing
DBMSs into the Grid.
P.Brezany
Institute for Scientific Computing – University of Vienna
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Basic Grid Database Requirements
• If database data is to be accessible in Grid applications, then a DBS
must support the relevant, existing, existing and emerging, Grid
standards; for example the Grid Security Infrastructure (GSI). These
standards should bear in mind the requirements of databases.
• A typical application may consist of a computation that queries one or
more databases and carries out further analysis on the retrieved data.
If the compute and database systems all conform to the same
standards for security, accounting, performance monitoring and
scheduling etc. then the task of building such applications will be
greatly simplified.
• Note: A Database System (DBS) is created, using a DBMS, to manage a
specific database. The DBS includes any associated application software. Many
Grid applications will need to utilize more than one DBS. To reduce the effort
required to achieve this, federated databases use a layer of middleware
running on top of autonomous databases, to present applications with some
degree of integration.
• Other requirements of applications on Grid-enabled DBMS: scalability,
handling unpredictable usage, metadata-driven access, multiple
database federation, etc.
P.Brezany
Institute for Scientific Computing – University of Vienna
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Integrating Databases into the Grid
• Grid-enabled version of JDBC/ODBC - The core set
of functionality offered by JDBC/ODBC does not
include a number of operations to fulfill Grid
database requirements.
• Service-based approach shown in the next slide,
with a service wrapper placed between the Grid and
the DBS
P.Brezany
Institute for Scientific Computing – University of Vienna
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Integrating Databases into the Grid (2)
P.Brezany
Institute for Scientific Computing – University of Vienna
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Federating Database Systems Across the Grid
P.Brezany
Institute for Scientific Computing – University of Vienna
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Grid Database Access
P.Brezany
Institute for Scientific Computing – University of Vienna
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Grid Database Access With OGSA-DAI
GDS gets a query via
Perform Document
GDS Engine process
specified activities
GDS returns results
P.Brezany
Institute for Scientific Computing – University of Vienna
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Grid Database Access With OGSA-DAI
P.Brezany
Institute for Scientific Computing – University of Vienna
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Grid Data Mediation Service (our own
development): Federation of Databases Architecture
P.Brezany
Institute for Scientific Computing – University of Vienna
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GDMS – Example Scenario
• Heterogeneities:
– Name in A is „Alexander Wöhrer“
– Name in C has to be combined
• Distribution:
– 3 data sources
P.Brezany
Institute for Scientific Computing – University of Vienna
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Literature Sources
http://www.cs.man.ac.uk/grid-db/
http://www.gridminer.org/
P.Brezany
Institute for Scientific Computing – University of Vienna
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