(for those requiring a worldcup update its 1-1. Now on overtime - interesting match. You can see the match live on your computer also using a TVU player - google it).
This is a question for which I have been trying to find an answer. I would appreciate any friendly enlightenment about the type of queries astronomers might have. Will the queries by astronomers be purely database-oriented or will it also lead to retrieval of image files from a data grid type of system? Case 1: Query the database using only astronomy related attributes to get result sets only from database. This is purely RDBMS here - traditional SQL type queries. Case 2: Query the database using only astronomy related attributes to get result sets from the database and some files or images. (its more DGMS style queries here) Case 3: Query the database using both astronomy related attributes and storage-related attributes to get result sets both from the database and image archive (e.g.) Query on ra, dec etc., and get these metadata, In addition get me the associated files only iff they can be retrieved with certain QoS or with a delivery time of these much hours. Or... I don't want 5TB of images coming out of this query but I am ok with 100GB. Thanks in advance, Arun ~~~~~~~~~ Luck is what happens when preparation meets opportunity. Arun swaran Jagatheesan http://www.sdsc.edu/~arun/ San Diego Supercomputer Center. (858)822.5452 > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Jacek Becla > Sent: Thursday, June 29, 2006 9:24 PM > To: LSST Data Management > Subject: [LSST-data] Database telecon Fri Jun 30 > > Keywords: DataAccWG > > Hi all, > > We will have a Database telecon this Friday at 11:00 AM PDT. > > I'd like to go over the latest disk io numbers. > > Here is the latest version: > > http://www.slac.stanford.edu/~becla/tmp/lsst_diskIO_estimates_v04.doc > http://www.slac.stanford.edu/~becla/tmp/lsst_diskIO_estimates_v04.xls > > > Shortly speaking the numbers looks very reasonable for > everything except two temporal queries, and both have the > same problem (see below) > > Phone number: 866 330 1200 > Pass code: 300 2363 > > Jacek > > ====================== > > Select time series data for given cone: > > SELECT o.objectId, o.ra, o.dec, i.MJD, d.* > FROM Object o, CCDImage i, DIASource d > WHERE o.ra BETWEEN ra1 + cos(decl1)*(0.5) > AND ra1 - cos(decl1)*(0.5) > AND o.decl between decl1 +0.5 and decl1 - 0.5 > AND o.objectId = d.objectId > AND d.ccdImageId = i.ccdImageId > ORDER BY o.objectId, i.MJD ASC > > > Object table: 10 million rows (one partition) > DIASource table: 45 billion rows > CCDImage table: 135 million rows > > > At the moment, if I assume a modest 1% selectivity for ra,dec > that gives 10K rows from Object table. > > Join with DIASource (5 DIASources per star) gives 50K rows, > then join with CCDImage (assuming 10K DIASources per > CCDImage) gives 50*10^12 rows. That is over a petabyte, which > now needs to be sorted, then for each row we need to fetch > full DIASource row.... > > > _______________________________________________ > LSST-data mailing list > [email protected] > http://www.lsstmail.org/mailman/listinfo/lsst-data > _______________________________________________ LSST-data mailing list [email protected] http://www.lsstmail.org/mailman/listinfo/lsst-data
