cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <>
Subject [Cassandra Wiki] Update of "FAQ" by RalphGoers
Date Sun, 30 Oct 2011 16:13:41 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.

The "FAQ" page has been changed by RalphGoers:

  == Why is it so hard to work with TimeUUIDType in Java? ==
  TimeUUID's are difficult to use from java clients because java.util.UUID does not support
generating version 1 (time-based) UUIDs.  Here is one way to work with them and Cassandra:
- Use the UUID generator from: Note that while a Type
1 UUID uses a granularity of 100 ns this UUID generator only uses milliseconds. Even with
100 ns granularity, with a Type 1 UUID it is still possible to get a duplicate UUID in a multi-threaded
application running on a processor with muliple CPUs unless the clock sequence is properly
incremented, which this UUID does not do (in this implementation the clock sequence is a random
number generated when the class is loaded).
+ Use the UUID generator from: See [[TimeBaseUUIDNotes
| Time based UUID Notes]]
  Below are three methods that are quite useful in working with the uuids as they come in
and out of Cassandra.

View raw message