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I am forwarding to qserv list... On 04/05/2016 02:32 PM, Srinivasan Chandrasekharan wrote: > Hi Jacek, > > I couldn’t think of anyone else to pose this DB problem to except you so > here it is. Requesting your input: > > So I have a catalog of 600 million stars. The data that I have is : > > ra, dec, muRa, muDec, …. some mag columns etc etc. > > I want to add a few columns, > > 1. Add column for each row that tells me how many stars I have in the > neighborhood with distance x. > 2. Add column for each row that tells me how many stars I have in the > neighborhood with distance x + 1. > > and so on …. > > The distances are of course in arcmin values. I guess the units dont > quite matter and I do know that if I use spatial indexes this problem > can be solved in SQL itself. > > I saw an old trac page > > https://dev.lsstcorp.org/trac/wiki/dbSpatialSupport > > Is there anything new that you know off that I could use? As you can see > the DB is 600 million rows so about 100GB of data in a single table so I > have to be slightly careful of what I execute. > > Just thought I would ask your opinion .. Just in case I am missing > something.. > > Regards, > > Srinivasan Chandrasekharan > Senior Software Engineer, > Large Synoptic Survey Telescope, > Tucson, AZ 85726 > Phone: (520) 318-8383 > Fax : (520) 318-8424 > Email : [log in to unmask] <mailto:[log in to unmask]> > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the QSERV-L list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=QSERV-L&A=1