Consider this scenario in a SQL database: UPDATE foo SET x = 1 WHERE key = 'asdf';
Now, "simultaneously," two clients run UPDATE foo SET x = 2 WHERE key = 'asdf'; and SELECT * FROM foo WHERE x = 1; Either you get back row asdf, or you don't. Either is valid. Same thing happens with Cassandra indexes. On Fri, Sep 9, 2011 at 10:41 AM, <alta...@ceid.upatras.gr> wrote: > I see that Cassandra updates secondary indices as soon as a value of the > indexed column is updated. This can happen, for example, during a select > query with a condition on a secondary index. Does Cassandra perform no > checking or locking? Will the result of this select, with old and new > values, be returned as is? Am I missing some reason why this isn't a > problem? > > Alexander > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
