Re: Questions about timestamp set at writetime
when inserting with a batch every row have the same timestamp; I also think (not 100%) that is not possible to define different timestamps within a batch. Tommaso 2014-06-17 14:10 GMT+02:00 DuyHai Doan doanduy...@gmail.com: Hello all I know that at write time a timestamp is automatically generated by the server and assigned to each column. My questions are: 1) Who is responsible for this micro-second timestamp ? The coordinator which receives the insert request or each replica which actually do persist the data ? 2) In a case of a batch insert (CQL3 batch, not batch mutation Thrift API), if no user defined timestamp is set, neither on the batch statement nor on each individual statement, will C* generate a SAME timestamp for each individual statement in the batch or will there distinct timestamps ? Regards Duy Hai DOAN
Re: Questions about timestamp set at writetime
that is not possible to define different timestamps within a batch -- It is possible : http://www.datastax.com/documentation/cql/3.1/cql/cql_reference/batch_r.html On Tue, Jun 17, 2014 at 2:17 PM, tommaso barbugli tbarbu...@gmail.com wrote: when inserting with a batch every row have the same timestamp; I also think (not 100%) that is not possible to define different timestamps within a batch. Tommaso 2014-06-17 14:10 GMT+02:00 DuyHai Doan doanduy...@gmail.com: Hello all I know that at write time a timestamp is automatically generated by the server and assigned to each column. My questions are: 1) Who is responsible for this micro-second timestamp ? The coordinator which receives the insert request or each replica which actually do persist the data ? 2) In a case of a batch insert (CQL3 batch, not batch mutation Thrift API), if no user defined timestamp is set, neither on the batch statement nor on each individual statement, will C* generate a SAME timestamp for each individual statement in the batch or will there distinct timestamps ? Regards Duy Hai DOAN
Re: Questions about timestamp set at writetime
thats going to be the timestamp for the data affected. what I meant is that you cant have different timestamps (insert x timestamp y; insert x' timestamp y') 2014-06-17 14:27 GMT+02:00 DuyHai Doan doanduy...@gmail.com: that is not possible to define different timestamps within a batch -- It is possible : http://www.datastax.com/documentation/cql/3.1/cql/cql_reference/batch_r.html On Tue, Jun 17, 2014 at 2:17 PM, tommaso barbugli tbarbu...@gmail.com wrote: when inserting with a batch every row have the same timestamp; I also think (not 100%) that is not possible to define different timestamps within a batch. Tommaso 2014-06-17 14:10 GMT+02:00 DuyHai Doan doanduy...@gmail.com: Hello all I know that at write time a timestamp is automatically generated by the server and assigned to each column. My questions are: 1) Who is responsible for this micro-second timestamp ? The coordinator which receives the insert request or each replica which actually do persist the data ? 2) In a case of a batch insert (CQL3 batch, not batch mutation Thrift API), if no user defined timestamp is set, neither on the batch statement nor on each individual statement, will C* generate a SAME timestamp for each individual statement in the batch or will there distinct timestamps ? Regards Duy Hai DOAN
Re: Questions about timestamp set at writetime
1) Who is responsible for this micro-second timestamp ? The coordinator which receives the insert request or each replica which actually do persist the data ? The coordinator. 2) In a case of a batch insert (CQL3 batch, not batch mutation Thrift API), if no user defined timestamp is set, neither on the batch statement nor on each individual statement, will C* generate a SAME timestamp for each individual statement in the batch or will there distinct timestamps ? All the sub-statements will have the same timestamp. -- Sylvain
Re: Questions about timestamp set at writetime
Thank you Sylvain for the very clear explanations On Tue, Jun 17, 2014 at 2:44 PM, Sylvain Lebresne sylv...@datastax.com wrote: 1) Who is responsible for this micro-second timestamp ? The coordinator which receives the insert request or each replica which actually do persist the data ? The coordinator. 2) In a case of a batch insert (CQL3 batch, not batch mutation Thrift API), if no user defined timestamp is set, neither on the batch statement nor on each individual statement, will C* generate a SAME timestamp for each individual statement in the batch or will there distinct timestamps ? All the sub-statements will have the same timestamp. -- Sylvain
