Let's say I have a table that has one column with a unique id as a
primary key, and then hundreds of columns of floats, although a large
fraction of cells are empty.

  I want to create an application that allows users to pick one or more
number columns, specify a condition (equality or inequality) for each
number column picked, and then get all rows that satisfy all the conditions
provided. An empty cell would mean condition is not fulfilled.

  (for example, find all rows for which column35 < 0.5 AND column72 > 1.5
AND column236 < 0.1)

  What's the best way to enable this? A secondary index for each number
column? Would I have to obtain all columns that satisfy one condition and
filter them down, or is there a better way? Does Cassandra support finding
out which index best to start with?


     Best, Oliver

Oliver Ruebenacker
Senior Software Engineer, Diabetes Portal
<http://www.type2diabetesgenetics.org/>, Broad Institute

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