Speaker
Dr
Alexandre Vaniachine
(ANL)
Description
In preparation for data taking, the ATLAS experiment has run a series of large-scale
computational exercises to test and validate distributed data grid solutions under
development. ATLAS experience in prototypes and production systems of Data Challenges
and Combined Test Team provided various database connectivity requirements for
applications: connection management, online-offline uniformity, server indirection,
etc. For example, the dynamics of ATLAS distributed database services requires a
single point-of-control over server indirection - the logical-to-physical database
server mapping, which is similar to the logical-to-physical mapping of file names on
the grids. To address these requirements we developed, tested and deployed ATLAS
database Client Library.
In a heterogeneous distributed database services environment ATLAS database Client
Library implements a consistent strategy for database server access and serves as a
foundation layer for enforcing policies, following rules, establish best practices
and encode logic to deliver efficient, secure and reliable database connectivity for
applications. To provide scalable and robust applications access to databases the
client library provides support for retries, failover, load balancing, etc. To hide
the complexity of heterogeneous database technologies the library is separated in two
layers. The outer layer provides management of database drivers, database connections
and Connections/Servers lists. The extensible inner library layer is composed of a
number of technology specific database drivers, currently supporting Oracle and MySQL.
We present architecture of the Client Library services integration in ATLAS software
framework Athena and use of these services by ATLAS major database applications – the
Geometry HVS DB and Conditions IOV DB. We report on ATLAS Client Library integration
through the ConnectionService module in the CORAL layer of the common LCG persistency
project POOL.
Summary
In a data grid environment ATLAS database Client Library improves database access
from applications.
Primary authors
Dr
Alexandre Vaniachine
(ANL)
Antoine Pérus
(LAL)
David Malon
(ANL)
Joseph Boudreau
(University of Pittsburgh)
RD Schaffer
(LAL)
Richard Hawkings
(CERN)
Torre Wenaus
(BNL)
Vakhtang Tsulaia
(University of Pittsburgh)
Yulia Shapiro
(CERN)
