Hi, Andrew, Conceptually, you are right, but the specific numbers may not be exactly as you indicated.
In a two-level index, the coarse bins are based on a criteria that is unlike to have the same number of fine bins in each coarse bin. You can find more information about how the two-level binning works in Section 7.1 of this paper <http://crd.lbl.gov/~kewu/ps/LBNL-60891.pdf>. John On 9/15/2009 1:33 PM, Andrew Olson wrote: > On Sep 15, 2009, at 4:11 PM, K. John Wu wrote: > > >> BEGIN Column >> name=start >> data_type=Unsigned >> minimum=0 >> maximum=100000000 >> index=<binning begin=0 end=1e8 nbins=10000/><encoding interval- >> equality/> >> END Column >> >> (note: index specification must on one line in -part.txt) >> >> This index can handle i_begin and i_end that are multiples of 10,000 >> efficiently. If you have "2000 < start < 78000" in a query, then the >> index is insufficient to resolve this range condition, FastBit will >> have to go back to the raw data. >> >> In the above example, the values 2000 and 78000 are multiples of 1000, >> therefore, you can increase nbins to 100000 and keep bin boundaries at >> the same resolution as the query boundaries. > > One follow up question: > > If nbins is 10000, does FastBit use the low resolution bins for > 10000-70000 and the high resolution bins for 2000-10000 and 70000-78000? > > Andrew > _______________________________________________ > FastBit-users mailing list > [email protected] > https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users _______________________________________________ FastBit-users mailing list [email protected] https://hpcrdm.lbl.gov/cgi-bin/mailman/listinfo/fastbit-users
