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The "SecondaryIndexes" page has been changed by DaveBrosius: http://wiki.apache.org/cassandra/SecondaryIndexes?action=diff&rev1=1&rev2=2 * Q: Is there a difference between creating a secondary index vs creating an "index" CF manually such as "users_by_country"? A: Yes. First, when creating your own index, a node may index data held by another node. Second, updates to the index and data are not atomic. + * Q: Why is it necessary to always have at least one EQ comparison on secondary indices? + A: 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. +
