Fermilab Computing Division

CS Document 448-v1

Using a Relational Database to House Metadata for the Common

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JoAnn Larson
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JoAnn Larson
Document Created:
03 Aug 2004, 11:44
Contents Revised:
23 Sep 2004, 16:26
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31 Jan 2005, 12:58
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03 Aug 2004, 11:44
SAM was developed as a data handling system for Run II at Fermilab. SAM is a
collection of services, each described by metadata. The metadata are modeled
on a relational database, and implemented in ORACLE. SAM, originally deployed in
production for the D0 Run II experiment, has now been also deployed at CDF
and is in testing at MINOS. This illustrates that the metadata decomposition of its
services has broader applicability than at just one experiment. We believe
this is the first example of such a unification, where two complex collider
experiments are sharing a schema for the complete description of file contents, file
locations, and processing descriptions. Metadata for several million files are now stored
for each experiment. Over the last five years, greater understanding of the
required services in a performant data handling system has emerged. The collection of
metadata to support these services forms the core of the SAM system. We
describe this schema and the commonalities and differences that emerge from the need
to support two experiments. We also describe the support structure required
for schema updates: the use of development, integration, and production
This talk will focus on the four categories of SAM services, the
functionality currently implemented in those services, and the supporting metadata we
collect for these services. We will also explore the SAM Entity Relationship diagram for
a visual means of understanding SAM and its functions, and some of the query
structure needed and some of the performance issues.
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Notes and Changes:
Talk prepared and presented by Rick St. Denis
Associated with Events:
CHEP2004 held from 27 Sep 2004 to 01 Oct 2004 in Interlaken, Switzerland
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