> So it seems it's not a good idea, to use Cassandra like that? Right. It's basically a table scan.
Here is some background on the approach simple geo took to using Cassandra... http://www.readwriteweb.com/cloud/2011/02/video-simplegeo-cassandra.php Also PostGis for Postgress seems popular http://postgis.refractions.net/ Hope that helps. ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 12/05/2012, at 4:23 AM, cyril auburtin wrote: > I was thinking of a CF with many many rows with id, type, latitude and > longitude (indexed), and do geolocation queries: type=all and lat < 43 and > lat >42.9 and lon < 7.3 and lon > 7.2 > > where all rows have type=all > (at least try how Cassandra deals with that) > So it seems it's not a good idea, to use Cassandra like that? > > There's also the possibly to do in parallel, other CF, with latitude in rows, > that will be sorted, so an indexed query can give us the right latidue range, > and then just query with logitude < and > > > What do you think of that > > thanks > > 2012/5/11 Dave Brosius <dbros...@mebigfatguy.com> > Inequalities on secondary indices are always done in memory, so without at > least one EQ on another secondary index you will be loading every row in the > database, which with a massive database isn't a good idea. So by requiring at > least one EQ on an index, you hopefully limit the set of rows that need to be > read into memory to a manageable size. Although obviously you can still get > into trouble with that as well. > > > > > On 05/11/2012 09:39 AM, cyril auburtin wrote: > Sorry for askign that > but Why is it necessary to always have at least one EQ comparison > > [default@Keyspace1] get test where birth_year>1985; > No indexed columns present in index clause with operator EQ > > It oblige to have one dummy indexed column, to do this query > > [default@Keyspace1] get test where tag=sea and birth_year>1985; > ------------------- > RowKey: sam > => (column=birth_year, value=1988, timestamp=1336742346059000) > > > >
