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Sylvain Lebresne updated CASSANDRA-4476: ---------------------------------------- Reviewer: Benjamin Lerer (was: Sylvain Lebresne) > Support 2ndary index queries with only inequality clauses (LT, LTE, GT, GTE) > ---------------------------------------------------------------------------- > > Key: CASSANDRA-4476 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4476 > Project: Cassandra > Issue Type: Improvement > Components: API, Core > Reporter: Sylvain Lebresne > Assignee: Oded Peer > Priority: Minor > Labels: cql > Fix For: 3.0 > > Attachments: cassandra-trunk-4476.patch > > > Currently, a query that uses 2ndary indexes must have at least one EQ clause > (on an indexed column). Given that indexed CFs are local (and use > LocalPartitioner that order the row by the type of the indexed column), we > should extend 2ndary indexes to allow querying indexed columns even when no > EQ clause is provided. > As far as I can tell, the main problem to solve for this is to update > KeysSearcher.highestSelectivityPredicate(). I.e. how do we estimate the > selectivity of non-EQ clauses? I note however that if we can do that estimate > reasonably accurately, this might provide better performance even for index > queries that both EQ and non-EQ clauses, because some non-EQ clauses may have > a much better selectivity than EQ ones (say you index both the user country > and birth date, for SELECT * FROM users WHERE country = 'US' AND birthdate > > 'Jan 2009' AND birtdate < 'July 2009', you'd better use the birthdate index > first). -- This message was sent by Atlassian JIRA (v6.3.4#6332)