may. 2004ivoa meeting / boston1 openskyquery,skynodes and adql william omullane johns hopkins...

May. 2004IVOA Meeting / Boston 1

OpenSkyQuery,SkyNodes and ADQL

William O’MullaneJohns Hopkins University

THE US NATIONAL VIRTUAL OBSERVATORY


Context

• SkyNode is a SOAP interface accepting ADQL and exposing metadata

• OpenSkyQuery is a demonstration portal which uses multiple nodes to perform distributed queries

• ADQL may be used by multiple services in DAL. E.g. upgraded CONE/SIAP services.


Since Last Time

• We had ADQL v0.3 spec combined with SkyNode

• Now we have SkyNode0.7.4 and ADQL 0.7.4 as separate specs

• We now also have ADQL 0.7.4 XSD (much input from M.Hill and Co.)

• We spoke of Open SkyQuery – Now we have a working version using ADQL0.7.4 and VOTable1.1(DataTable).

• Page to gather comments fro ADQL 0.8


Virtual Observatory Query Language Layers (Cambridge)

VOQL3 SkyXQuery

VOQL2 SkyQL

VOQL1 WebServices

XML-based semantically rich query language.

Portals combining ADQL services e.g. OpenSkyQuery

Astronomical Data Query Language (ADQL) and VOTABLE to exchange information between machines e.g. SkyNode


ADQL/x ADQL/s - remains

• Same semantics different syntax• ADQL/x - parse tree easy for SkyNodes• ADQL/s – textual easy for humans• ADQL Includes, regions, Xmatch (parser

only for circle now),math functionsSome people still want one or the other • Simple parser working both ways

ADQLtoSkyQL SkyQLtoADQL


ADQL old and new<Selection>

<Items>

<SelectionItem xsi:type="ExprSelectionItem">

<Expr xsi:type="ColumnExpr">

<Column xsi:type="AllColumnReference">

<TableName>a</TableName>

</Column> </Expr>

</SelectionItem> </Items>

</Selection>

<TableClause>

<FromClause>

<TableReference>

<Table>

<Name>Tab</Name>

<AliasName>a</AliasName>

</Table> </TableReference> ..

<Select xmlns:xsd…ADQL/v0.7.4">

<SelectionList>

<Item xsi:type="columnReferenceType" Table="a" Name="*" />

</SelectionList>

<From>

<Table xsi:type="tableType" Name="Tab" Alias="a" />

</From>

</Select>

Select a.* from Tab a

0.7.1 0.7.4


Architecture not changed March 2004


SkyNode

• Interface for tables,columns etc.• Interface for PerformQuery• Interface for ExecutePlanWhat is the Node Interface?NEED• Portal Interface for trackingLets see the PORTAL


Exec plan

SKYNODE 3SKYNODE 2SKYNODE 1

CLIENTPORTAL

2. ExecPlan

T3 resultT2 result

1.Performance Queries


What to do with an ExecPlan

ExecPlan List of nodes + Queries, sent from portal

• If I am the last node – run query return result.1. If not pass on to the next node in the list and

await response.2. Upload response table3. Perform Xmatch4. Join result of Xmatch to the original query5. Return the result


Problems

• Main delay going from ADQL0.7.1 -> 0.7.4

• Votable1.1 – not working with XSD.exe or JAXB – VOtables produced are not in good format. Problems with the tools. Choice caused some problems linked with AnyType


Future

• MYDB- ala CasJobs does all of this (short demo)– http://casjobs.fnal.gov

• Identification across nodes – federated trust. WS-Security/ Now will be in line with WS-REF for grid.


Identification across Nodes

• Need user identification across nodes– Centralize (not nice technically nor politically)– How to integrate with exiting mysapce and MYDB …

• Federate ! (IBM/MS Paper )– Authentication service on each node– User signs up anywhere or uses exisiting id– Accept userids issued by trusted nodes

• Authenticate userid with node it is supposed to be from

• Working with Savas Parastatatis on this

may. 2004ivoa meeting / boston1 openskyquery,skynodes and adql william omullane johns hopkins...

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