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

3. Schema and views I CPULoad (Global Schema) CountrySiteFacilityLoadTimestamp UKRALCDF0.319055711022002 UKRALATLAS1.619055611022002 UKGLACDF0.419055811022002 UKGLAALICE0.519055611022002 CHCERNALICE0.919055611022002 CHCERNCDF0.619055511022002 CPULoad (Producer3) CHCERNATLAS1.619055611022002 CHCERNCDF0.619055511022002 CPULoad (Producer 1) UKRALCDF0.319055711022002 UKRALATLAS1.619055611022002 CPULoad (Producer 2) UKGLACDF0.419055811022002 UKGLAALICE0.519055611022002

4. Schema and Views II CPULoad (Producer 1) UKRALCDF0.319055711022002 UKRALATLAS1.619055611022002 CPULoad (Producer 2) UKGLACDF0.419055811022002 UKGLAALICE0.519055611022002 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 9 th 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 NetworkMonitor NM1NM2ToolMeasurement RALLyonPinger1500 RALCERNPinger800 ComputingElement NameNM… RALQ1RAL… CERNQ1CERN… LyonQ1Lyon… StorageElement NameNM… RALS1RAL… CERNS1CERN… LyonS1Lyon… 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 S.NameC.NameMeasure ment RALS1CERNQ1800 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???