Presentation on theme: "Sept. 2003NVO Team Meeting / Victoria1 VOQL/ADQL/MYDB for VO William OMullane Johns Hopkins University T HE US N ATIONAL V IRTUAL O BSERVATORY."— Presentation transcript:
Sept. 2003NVO Team Meeting / Victoria1 VOQL/ADQL/MYDB for VO William OMullane Johns Hopkins University T HE US N ATIONAL V IRTUAL O BSERVATORY
Sept. 2003NVO Team Meeting / Victoria2 Virtual Observatory Query Language Layers VOQL3 SkyXQuery VOQL2 SkyQL VOQL1 WebServices future XML-based query language. SQL-like query language and federation system i.e. combination of SkyQuery, JVOQL and VO standards Astronomical Data Query Language (ADQL) and VOTABLE to exchange information between machines
Sept. 2003NVO Team Meeting / Victoria3 Architecture Clients VOQL Portal High Level Language allowing seemingly uniform access to services. VOQLQuery IVOA SkyNodes Lower level ADQL (including regions) and services to Support VOQL. laterEnd 2003 Tables MetaData PerformQuery Columns LEV1 Tables MetaData PerformQuery Columns LEV2 XMatch Tables MetaData PerformQuery Columns LEV1 Registry Register Tables MetaData PerformQuery Columns LEV4 XMatch ExecPlan Footprint Tables MetaData PerformQuery Columns LEV3 XMatch ExecPlan Open SkyQuery Portal Uses only Registry, Lev3 and Lev4 SkyNodes. SkyQuery SkyQuery WebApp May use Services at any level SKYQLADQLVOQLADQL
Sept. 2003NVO Team Meeting / Victoria4 SkyNode Levels FeatureLEV1– ADQL LEV2 – XMATCH LEV3- SKYNODE LEV4- SKYNODE Advanced Optional ADQL – circle XXXX Xmatch XXX Performance Query XX Takes exec plan XX Footprint – Region intersect X MYDB X Authentication X
Sept. 2003NVO Team Meeting / Victoria5 SkyQL and ADQL Same semantics different syntax ADQL - parse tree easy for SkyNodes SkyQL – textual easy for humans ADQl Includes Rots regions, Xmatch,math functions Simple parser working both ways(demo) ADQLtoSkyQLADQLtoSkyQL SkyQLtoADQLSkyQLtoADQL
Sept. 2003NVO Team Meeting / Victoria6 MYDB – not in v0.4 local space for data and results –Like astorgrid mysapce Requires on node –User Identification –Job tracking/monitoring –Asynchronous execution CasJobs does all of this (short demo) –http://skyservice.pha.jhu.edu/devel/casjobshttp://skyservice.pha.jhu.edu/devel/casjobs Should we try to do this for OpenSkyQuery now? What about across nodes…
Sept. 2003NVO Team Meeting / Victoria7 MYDB 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 )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
Sept. 2003NVO Team Meeting / Victoria8 Security with federated Auth. How secure do we want this? Should the userid be: – an encrypted token – just a number Do we copy user info to each node so we can have integrity constarins in our db on USERID
Sept. 2003NVO Team Meeting / Victoria9 MYVOSPACE Next step is an integration service One stop service
Sept. 2003NVO Team Meeting / Victoria10 Current Issues for discussion Since v0.3
Sept. 2003NVO Team Meeting / Victoria11 Hardcore Levels Drop Lev3 Skynode Require Footprint/Region intersect for Skynodes. Personally – I think we will have nodes without and would rather have a name for them
Sept. 2003NVO Team Meeting / Victoria12 Interface Issue Currently PerformQuery returns VOTable Votable performQuery (ADQL query) M.Hill would like a more general wrapper e.g. IVOAResult performQuery (ADQL query) Here IVOAResult would be abstract or a wrapper containing VOTable or some pointer to a file. Would also allow for putting other things in result (region densities Yasuda San has suggested).
Sept. 2003NVO Team Meeting / Victoria13 Neighbours or XMatch Xmatch is a probabilistic matching returning all neighbours taking account of errors. B. Mann suggests we should use lowest common denominator which is Neighbors – this would return all objects within a certain distance of each other not using the errors.
Sept. 2003NVO Team Meeting / Victoria14 Region Specification Issue Have suggested Region,RefionUrl,RegionXml. Region would take simple strings like Circle j A.Rots has another suggestion for Region strings which is comprehensive Is this as complex as just using the XML …
Sept. 2003NVO Team Meeting / Victoria15 A. Rots Region Strings define CSys = (TimeFrame = (TimeScale='TT') and (TimeRefPosition='TELESCOPE')) and (SpaceFrame = (CoordFrame='ICRS') and (CoordRefPosition='TELESCOPE')) and (SpectralFrame = 'OBSERVATORY') and (CoordFlavor = 'SPHERICAL') define CArea = (TimeInterval = (StartTime=(ISOTime=' ')) and (StopTime=(ISOTime=' '))) and (Region = (Circle = (Center='60.0d,30.0d') and +(Radius='10arcmin')) and (SpectraLinterval = (LoLimit='1GHz') and (HiLimit='2GHz')) define CSpec = (Time = (CoordResolution<='10s')) and (Pos2Vector = (CoordResolution<='10arcsec,10arcsec')) and (Spectrum = (CoordResolution<='50MHz')) The query: select from where and SearchLocation = (CoordSystem = $CSys and CoordArea = $CArea