We are facing an issue while copying rows from a Cassandra columnfamily to MySQL table. Cassandra version in-use is 2.0.4 and Kettle version is 5.0.1.

The transformation uses a Cassandra Input element to specify source object & query and a Table output for the MySQL destination table. The Cassandra columnfamily object being copied has approx 0.5 million rows and each row is around 1KB in size on an average.

There are no problems in copying rows when no explicit limit clause is specified in the CQL query. Limit sizes of up-to 0.2 to 0.25 million does not encounter any errors in processing.

But, errors occur as soon as the limit size is increased to 0.4 to 0.5 million. Some of the error messages that frequently occurs are Java heap space Outof Memory error and GC overhead limit exceeded error.

Look forward to valued suggestions on ways to resolve this issue.