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R-GMA – an Update

R-GMA – an Update. A reminder of R-GMA The need for a mediator Work with WP7 Release 1.2 and beyond Some Implications of OGSA. Application Code. Application Code. Archiver Servlet. Consumer Servlet. Consumer Servlet. Consumer Servlet. Consumer Servlet. Consumer API. Archiver API.

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R-GMA – an Update

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  1. R-GMA – an Update • A reminder of R-GMA • The need for a mediator • Work with WP7 • Release 1.2 and beyond • Some Implications of OGSA

  2. Application Code Application Code Archiver Servlet Consumer Servlet Consumer Servlet Consumer Servlet Consumer Servlet Consumer API Archiver API Consumer API Consumer API Consumer API Registry API Registry API Registry API Registry API Consumer API DBProducer Registry Servlet Schema API DBProducer Servlet Registry API ProducerServlet Producer API Schema Servlet Sensor Code “Event Dictionary” R-GMA Architecture

  3. Schema and views I

  4. Schema and Views II WHERE Country = ‘UK’ AND Site = ‘RAL’ WHERE Country = ‘UK’ AND Site = ‘GLA’ SELECT load FROM CPULoad WHERE Site=‘GLA’ SELECT load FROM CPULoad WHERE Facility=‘CDF’

  5. The need for a Mediator • The set of tables producers publish constitute a global relational schema • Individual producers contribute “views” on this global virtual database • Views can themselves be expressed in SQL • Queries against the global schema have to be matched with suitable producers • This soon becomes complicated due to issues of soundness and completeness of producers

  6. Work with WP7 The round trip time from RAL to Lyon as measured pinger was 500 ms on the 9th November at 11:00. : (RAL, Lyon, Pinger, 1500, 001-11-09T11:00Z) A set of such tuples could be stored in a table: NetworkMonitor(NM1, NM2, Tool, Measurement, Time/Date) Any structured data can be represented in tables in this manner. Complex queries can be formulated with SQL.

  7. Example SELECT S.Name, C.Name, Measurement FROM NetworkMonitor N, ComputingElement C, StorageElement S WHERE S.NM = N.NM1 AND C.NM = N.NM2 AND MEASUREMENT < 1000 SELECT S.Name, C.Name FROM ComputingElement C, StorageElement S WHERE S.NM = C.NM

  8. Release 1.2 and beyond • Without Mediator use Archiver to assemble Networking information • Simple Mediator for producers that register predicates of the form WHERE attr1=val1 AND attr2=val2 … • Error Handling over Network Link • Work on C API has started • Work on integration of R-GMA and Prove and R-GMA has started

  9. Implications of OGSA • OGSA stresses a services model • R-GMA is constructed in this spirit • Producers use services of ProducerServlets etc. • OGSA builds on SOAP and WSDL • We could easily use SOAP as the communication protocol and refactor servlets into beans called from a SOAP router • Need to look into WSDL • What is the Future of MDS within OGSA???

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