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Posted to dev@cassandra.apache.org by kedar mhaswade <ke...@gmail.com> on 2017/05/03 01:02:08 UTC

A (drop-in) replacement for ColumnFamilyRecordReader in C*3?

Hello Cassandra Devs,

See https://issues.apache.org/jira/browse/CASSANDRA-10996. This JIRA tells us the schema changes between C*2 and C*3. Sylvain Lebresne suggests that one should use the KeyspaceMetadata and related classes from the DataStax driver instead of running queries against the internal schema keyspaces which have also moved. 

My problem is related to CASSANDRA-10996, although unlike the reporter of that report, I am not doing a query like that. It's a Cassandra 2.2 class itself that does a similar query for me. This class is org.apache.cassandra.hadoop.ColumnFamilyRecordReader which is used as-is (via a wrapper) in one of the projects I am working on (JanusGraph). Since this class is not found on Cassandra trunk, there must be something that replaces its functionality (hopefully a drop-in replacement). And the way it fails JanusGraph is documented in this bug: https://github.com/JanusGraph/janusgraph/issues/172.

I have two questions in this regard:
1- Is there a replacement for CFRR?
2- If not, can someone provide a way to replace ColumnFamilyRecordReader functionality, hopefully with some example code? I am thinking that we could wrap org.apache.cassandra.hadoop.cql3.CqlRecordReader instead of CFRR, but I need a bit more context before I embark on that adventure.

Thanks and Best Regards,
Kedar


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Re: A (drop-in) replacement for ColumnFamilyRecordReader in C*3?

Posted by Jeff Jirsa <jj...@gmail.com>.
Changing your code to wrap org.apache.cassandra.hadoop.cql3.CqlRecordReader is probably easier than trying to bring the old thrift based record reader into the 3.0 world, but I don't have any concrete code examples.

-- 
Jeff Jirsa


> On May 2, 2017, at 6:02 PM, kedar mhaswade <ke...@gmail.com> wrote:
> 
> Hello Cassandra Devs,
> 
> See https://issues.apache.org/jira/browse/CASSANDRA-10996. This JIRA tells us the schema changes between C*2 and C*3. Sylvain Lebresne suggests that one should use the KeyspaceMetadata and related classes from the DataStax driver instead of running queries against the internal schema keyspaces which have also moved. 
> 
> My problem is related to CASSANDRA-10996, although unlike the reporter of that report, I am not doing a query like that. It's a Cassandra 2.2 class itself that does a similar query for me. This class is org.apache.cassandra.hadoop.ColumnFamilyRecordReader which is used as-is (via a wrapper) in one of the projects I am working on (JanusGraph). Since this class is not found on Cassandra trunk, there must be something that replaces its functionality (hopefully a drop-in replacement). And the way it fails JanusGraph is documented in this bug: https://github.com/JanusGraph/janusgraph/issues/172.
> 
> I have two questions in this regard:
> 1- Is there a replacement for CFRR?
> 2- If not, can someone provide a way to replace ColumnFamilyRecordReader functionality, hopefully with some example code? I am thinking that we could wrap org.apache.cassandra.hadoop.cql3.CqlRecordReader instead of CFRR, but I need a bit more context before I embark on that adventure.
> 
> Thanks and Best Regards,
> Kedar
> 
> 
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> To unsubscribe, e-mail: dev-unsubscribe@cassandra.apache.org
> For additional commands, e-mail: dev-help@cassandra.apache.org
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