Amy Krause EPCC OGSA-DAI An Overview OGSA-DAI on OMII 2.0 OMII The Open Middleware Infrastructure Institute NeSC, Edinburgh, 14 September 2005

14 March 2005http:// Goals for this presentation Overview of OGSA-DAI How to install, configure and use OGSA-DAI WSI 1.0 on OMII 2.0

14 March 2005http:// Goals for OGSA-DAI Aim to deliver application mechanisms that: –Meet the data requirements of Grid applications –Functionality, performance and reliability –Reduce development cost of data centric Grid applications –Provide consistent interfaces to data resources –Acceptable and supportable by database providers –Trustable, imposed demand is acceptable, etc. –Provide a standard framework that satisfies standard requirements A base for developing higher-level services –Data federation –Distributed query processing –Data mining –Data visualisation

14 March 2005http:// Terminology - Data Data Resource –Any object that can source/sink data –Example: relational databases, a file system Data Service –Common interface to a data resource –Exposes capabilities of the data resource –SQL Queries, XPath Queries –May provide additional capabilities –Data transformations, 3 rd party data delivery OGSA-DAI –Open Grid Services Architecture Data Access and Integration

14 March 2005http:// OGSA-DAI in a Nutshell All you need to know about OGSA- DAI in a handy pocket sized book! Updated for Version 6.0

14 March 2005http:// High Level Design Data RelationalXML File Business Logic Presentation DAI Core WS-RFOGSI WS-I Client Server Client Toolkit API WS-RFOGSI WS-I OGSA-DAI Data Services SOAP over HTTP WS-RFOGSI WS-I

14 March 2005http:// OGSA-DAI Services OGSA-DAI uses data services to represent and provide access to a number of data resources accesses represents Data Service Data Resource Data Resource Data Resource accesses

14 March 2005http:// Data Service XindiceMySQLOracleDB2 Data source abstraction behind data service –plug in data resources for different data source technologies –does not mandate any particular query language or data format Heterogeneity

14 March 2005http:// Multiple Service Interfaces WS-I: –WSDL, SOAP, WS-I 1.0. –Axis 1.2, OMII 1.0 or OMII 2.0 WS-RF: –WS-Addressing, WS-RF. –Globus Toolkit 4. OGSI (deprecated in R7): –OGSI 1.0. –Globus Toolkit 3.

14 March 2005http:// Supported Data Resources RelationalXMLOther MySQL Xindice Files DB2 eXist ? Oracle PostgreSQL SQLServer

14 March 2005http:// Activities An Activity dictates an action to be performed, e.g. –Query a data resource –Transform data –Deliver results Engine processes a sequence of activities Subset of activities available to a Data Resource –Specified in configuration files Data can flow between activities HTML data WebRowSet xml data SQL Query Statement XSLT Transform Delivery ToURL

14 March 2005http:// OGSA-DAI Deck of Activities

14 March 2005http:// Client Toolkit Why? Nobody wants to write XML! A programming API which makes writing applications easier –Now: Java –Next: Perl, C, C#? // Create a query SQLQuery query = new SQLQuery(SQLQueryString); ActivityRequest request = new ActivityRequest(); request.addActivity(query); // Perform the query Response response = gds.perform(request); // Display the result ResultSet rs = query.getResultSet(); displayResultSet(rs, 1);

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource Data Resource1Data Resource2 List Resources

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource List Resources Data Resource1Data Resource2 Data Resource1 Data Resource2 Data Resource3

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource Data Resource1Data Resource2 Query To: Data Resource1 Select name from …

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource Query Data Resource1Data Resource2 …

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource Query + Delivery Data Resource1Data Resource2

14 March 2005http:// Interaction Examples Data Resource3 Container Client Data Service Data Resource Query Data Resource1Data Resource2 …

14 March 2005http:// Why OGSA-DAI? Why use OGSA-DAI over JDBC? –Can embed additional functionality at the service end –Transformations, compressions –Third party delivery –The extensible activity framework –Avoiding unnecessary data movement –Common interface to heterogeneous data resources –Relational, XML databases, and files –Usefulness of the Registry for service discovery –Dynamic service binding process –Provision of good meta-data is necessary –Language independence at the client end –Do not need to use Java –Platform independence –Do not have to worry about connection technology, drivers, etc

14 March 2005http:// Current release: OGSA-DAI WS-I 1.0 Based on Apache Axis, also works with OMII 2.0 middleware distribution –An OGSA-DAI “Data Service” combining metadata, configuration and perform document capabilities –Access to service metadata provided by a partial implementation of the WS-ResourceProperties specification. –Example clients for testing and coding reference. –Client Toolkit Caveats/Issues: –No security support –Interfaces will be extended for R7

14 March 2005http:// OGSA-DAI Project Webpage Background News & Events Software Releases Documentation On-line Tutorials Support Training Courses Links

14 March 2005http:// FAQ, Support, Mailing List Frequently Asked Questions – –Updated as common problems become clear Support for OGSA-DAI releases – –Use to report problems Discussion list – –General discussion of OGSA-DAI, data and the Grid