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From Igor <i...@4friends.od.ua>
Subject please explain read path when key not in database
Date Tue, 26 Feb 2013 13:40:39 GMT
Hello!

Explain please, how this work when I request for key which is not in 
database

  * The closest node (as determined by proximity sorting as described
    above) will be sent a command to perform an actual data read (i.e.,
    return data to the co-ordinating node).
  * As required by consistency level, additional nodes may be sent
    digest commands, asking them to perform the read locally but send
    back the digest only.
      o

        For example, at replication factor 3 a read at consistency level
        QUORUM would require one digest read in additional to the data
        read sent to the closest node. (SeeReadCallback
        <http://wiki.apache.org/cassandra/ReadCallback>, instantiated
        byStorageProxy <http://wiki.apache.org/cassandra/StorageProxy>)


I have multi-DC with NetworkTopologyStrategy and RF:1 per datacenter, 
and reads are at consitency level ONE. If local node responsible for key 
replied that it have no data for this key - will coordinator send digest 
commands?

Thanks!

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