Hi Alexandre. I wrote to ‘user@cassandra.apache.org’.
Re the actual problem: I am aware of the fact that C* does not store (need not store) the timezone as it is persisted as a Unix epoche timestamp. Not delivering a timezone in the JSON text representation would be OKish if the text representation would be guaranteed to be in UTC. But it is not. It is in some timezone determined by the locale of the server side or that of the client VM. That way it is a pain in two ways as a) I have to add the timezone in a post-processing step to all timestamps in my JSON responses and b) I also have to do some guesswork at what the actual timezone might be If there is no way to control the formatting of JSON timestamps and to add the time zone information, then IMHO that is bug. Is it not? Or am I missing something here? Thanks! Ralf > On 08.02.2016, at 12:06, Alexandre Dutra <alexandre.du...@datastax.com> wrote: > > Hello Ralf, > > First of all, Cassandra stores timestamps without timezone information, so > it's not possible to retrieve the original timezone used when inserting the > value. > > CQLSH uses the python driver behind the scenes, and my guess is that the > timestamp formatting is being done driver-side – hence the timezone – while > when you call toJson(), the formatting has to be done server-side. > > That said, it does seem that Cassandra is using a format without timezone > when converting timestamps to JSON format: > https://github.com/apache/cassandra/blob/cassandra-3.0/src/java/org/apache/cassandra/serializers/TimestampSerializer.java#L52 > > <https://github.com/apache/cassandra/blob/cassandra-3.0/src/java/org/apache/cassandra/serializers/TimestampSerializer.java#L52> > > I agree with you that a date format that would include the timezone would be > preferable here, but that is a question you should ask in the Cassandra Users > mailing list instead. > > Hope that helps, > > Alexandre > > > > > On Mon, Feb 8, 2016 at 11:09 AM Ralf Steppacher <ralf.viva...@gmail.com > <mailto:ralf.viva...@gmail.com>> wrote: > Hello all, > > When I select a timestamp as JSON from Cassandra, the string representation > lacks the timezone information, both via CQLSH and the Java Driver: > > cqlsh:events> select toJson(created_at) AS created_at from > event_by_patient_timestamp ; > > created_at > --------------------------- > "2016-01-04 16:05:47.123" > > (1 rows) > > vs. > > cqlsh:events> select created_at FROM event_by_user_timestamp ; > > created_at > -------------------------- > 2016-01-04 15:05:47+0000 > > (1 rows) > cqlsh:events> > > To make things even more complicated the JSON timestamp is not returned in > UTC. Is there a way to either tell the driver/C* to return the JSON date in > UTC or add the timezone information (much preferred) to the text > representation of the timestamp? > > > Thanks! > Ralf > -- > Alexandre Dutra > Driver & Tools Engineer @ DataStax
