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Jonathan Ellis commented on CASSANDRA-4175: ------------------------------------------- And extremely collision-prone. :) > Reduce memory (and disk) space requirements with a column name/id map > --------------------------------------------------------------------- > > Key: CASSANDRA-4175 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4175 > Project: Cassandra > Issue Type: Improvement > Reporter: Jonathan Ellis > Fix For: 1.2 > > > We spend a lot of memory on column names, both transiently (during reads) and > more permanently (in the row cache). Compression mitigates this on disk but > not on the heap. > The overhead is significant for typical small column values, e.g., ints. > Even though we intern once we get to the memtable, this affects writes too > via very high allocation rates in the young generation, hence more GC > activity. > Now that CQL3 provides us some guarantees that column names must be defined > before they are inserted, we could create a map of (say) 32-bit int column > id, to names, and use that internally right up until we return a resultset to > the client. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira