Issues with the WS-DAIR (GFD 76) Recommendation

This page outlines issues with the Web Services Data Access and Integration – The Relational Realisation (WS-DAIR) Specification, Version 1.0 . A number of groups have reported issues with this proposed recommendation, mainly:

• OGSA-DAI
• AMGA

WSDL Issues

From the OGSA-DAI group, these occur from the Eclipse WSDL validator.

• The part 'GetSQLPropertyDocumentRequest' has an invalid value 'GetDataResourcePropertyDocumentRequest' defined for its element. Element declarations must refer to valid values defined in a schema.
  • The above error or warning does not appear with gSOAP used in AMGA WS-DAIR.
• The part 'GetSQLResponsePropertyDocumentRequest' has an invalid value 'GetDataResourcePropertyDocumentRequest' defined for its element. Element declarations must refer to valid values defined in a schema.
  • The above error or warning does not appear with gSOAP used in AMGA WS-DAIR.
• Cannot resolve the name 'wrs:metadata' to a(n) 'element declaration' component.
• The part 'GetSQLRowsetPropertyDocumentRequest' has an invalid value 'GetDataResourcePropertyDocumentRequest' defined for its element. Element declarations must refer to valid values defined in a schema.
  • The above error or warning does not appear with gSOAP used in AMGA WS-DAIR.

However, the Eclipse WSDL Validator has problems validating certain WSDL/XML Schemas, especially those whose definitions involve multiple namespaces and are spread over multiple files.

From the AMGA :

• WSDL Changes made for AMGA WS-DAIR Implementation AMGA WSDL Changes.doc

Binding Issues

• OGSA-DAI WS-DAIR uses rpc/literal.
  • However a change to document/literal was easily done with no changes required to the OGSA-DAI WS-DAIR source code.
• AMGA WS-DAIR uses document/literal
  • To change AMGA WS-DAIR to use rpc/literal, it was necessary to modify the given WSDLs a lot with gSOAP. difference in the WSDL between rpc and document

Some documentation on the differences between rpc/literal and document/literal from ibm, microsoft.

This was resolved by adopting a document/literal approach for both implementations. The conversion of OGSA-DAI to work with a document/literal binding was relatively painless. The rationale for using a document/literal binding was the precedence set by the OGSA-ByteIO WG in mandating it for their interop festival (see section 2.1 of the ByteIO Interoperability Testing Specification; the fact that WSRF recommend this type of binding (see this message) and the document/literal style offers a certain degree of decoupling from the operations and its associated messages (the elements have to be there but these do not have to comply with a specific XML Schema), see this message .

Large size data Issues

From the AMGA :

• Requesting very large data sizes (about 2Gb) increases the response time enormously, and even it may cause the service crash.
  • There was TCP connection Timeout when very large size of data was requested to OGSA-DAI WS-DAIR.
  • It caused AMGA WS-DAIR to crash, because it consumes very large amount of memory. To solve this The current AMGA WS-DAIR implementation just returns limited size of data which is defined in the config file. It means that it does not return all the data requested. So, a user need to check the property filed of Webrowset in order to see whether it returns all the data requested.

• Possible solutions
  • to define a fault message on Requesting too large size of data - this was the solution adopted
  • to extend the specification to allow the implementation to use soap streaming

Test Suite

From the AMGA :

• SQL query test : NIST SQL Test-Suite http://www.itl.nist.gov/div897/ctg/sql_form.htm
  • AMGA supports SQL-92 Entry-level "Direct Data Statements". (Some of Intermideate level are also supported such as JOIN)
  • The used SQLs for testing can be found at the AMGA source code (src/sqlparser/test/sql directory)
  • Testing program is deeply coupled with the AMGA source code.
• WS-DAIR interface test : SoapUI tool & self-defined test suite for AMGA WS-DAIR
  • Please refer the attachments (wsdair_project.xml should be used with the SoapUI tool)

• New Unified Test suite : wsdair_test_0_1.zip
  • usable for both of AMGA and OGSA-DAI WS-DAIR
  • service endpoint can be set as project's properties
  • elementFormDefault="qualified" for all xsd files
  • based on OGSA-DAI WS-DAIR schema

Test EndPoint

• AMGA : 150.183.250.215 port 8844

• OGSA-DAI WSDAIR 1.0 (rpc/literal)
  • URL: daiserver.epcc.ed.ac.uk port 20200
  • Resource ID: wsdai:BookDB Database table: dair_littleblackbook
  • Further information
  • Creating a test database with stored procedures

• OGSA-DAI WS-DAIR 1.0 + document/literal + bug fixes
  • URL: daiserver.epcc.ed.ac.uk port 20300
  • Resource ID: wsdai:BookDB Database table: dair_littleblackbook
  • Resource ID: wsdai:BookDBInterop Database table: littleblackbook - for WS-DAIR inter-op.

• OGSA-DAI WS-DAIR 1.0 + document/literal + bug fixes + uses WS-DAI/R XML Schema/WSDL which defines elementQualifiedDefault="true"
  • URL: daiserver.epcc.ed.ac.uk port 20400
  • Resource ID: wsdai:BookDB Database table: dair_littleblackbook
  • Resource ID: wsdai:BookDBInterop Database table: littleblackbook - for WS-DAIR inter-op.

• OGSA-DAI-WS-DAIR.doc

Informal inter-op notes

• Notes on AMGA and OGSA-DAI inter-op tests
• Notes on SoapUI and OGSA-DAI inter-op tests
• Simple Interoperabilty testing between AMGA client and OGSA-DAI server AMGA_Client_To_OGSADAI_Server_TEST_20090527.doc
• Simple Interoperabilty testing between OGSA-DAI client and AMGA server OGSADAIClient_To_AMGA_Server_TEST_20090602.doc

Inter-op tests

• Official inter-op test report with test suite definition, AMGA and OGSA-DAI results and recommendations to the spec authors. DAIR-Interop-test.doc
• Inter-op test suite for use with SoapUI tool
  • AMGA's initial version
    • wsdair_project_amga 0.3.xml
  • OGSA-DAI version with additional tests and fixes to existing tests (has AMGA XML Schema/WSDL embedded)
    • wsdair_project_amga 0.4.xml
  • Copy of the above but with OGSA-DAI WS-DAIR XML Schema/WSDL embedded
    • wsdair_project_ogsadai 0.4.xml
  • Copy of the above which uses WS-DAI/R XML Schema/WSDL which defines elementQualifiedDefault="true"
    • wsdair_project_ogsadai_namespace 0.4.xml

Attachments:

wsdair_test_0_1.zip [IssuesWithTheWSDAIRProposedRecommendation/wsdair_test_0_1.zip] wsdair_project_ogsadai 0.4.1.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project_ogsadai 0.4.1.xml] wsdair_project_ogsadai_namespace 0.4.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project_ogsadai_namespace 0.4.xml] wsdair_project_ogsadai 0.4.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project_ogsadai 0.4.xml] wsdair_project_amga 0.4.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project_amga 0.4.xml] wsdair_project_amga 0.3.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project_amga 0.3.xml] OGSADAIClient_To_AMGA_Server_TEST_20090602.doc [IssuesWithTheWSDAIRProposedRecommendation/OGSADAIClient_To_AMGA_Server_TEST_20090602.doc] WS-DAIR-CommentsExperiences.doc [IssuesWithTheWSDAIRProposedRecommendation/WS-DAIR-CommentsExperiences.doc] OGSA-DAI-WS-DAIR.doc [IssuesWithTheWSDAIRProposedRecommendation/OGSA-DAI-WS-DAIR.doc] AMGA_Client_To_OGSADAI_Server_TEST_20090527.doc [IssuesWithTheWSDAIRProposedRecommendation/AMGA_Client_To_OGSADAI_Server_TEST_20090527.doc] AMGA WSDL Changes.doc [IssuesWithTheWSDAIRProposedRecommendation/AMGA WSDL Changes.doc] DAIR-Interop-test.doc [IssuesWithTheWSDAIRProposedRecommendation/DAIR-Interop-test.doc] base.zip [IssuesWithTheWSDAIRProposedRecommendation/base.zip] wsdair_project.xml [IssuesWithTheWSDAIRProposedRecommendation/wsdair_project.xml]