Raja, To what system are you migrating? If it is a straight DB migration, you should be able to use ExecuteSQL -> PutDatabaseRecord. Just make sure your Fetch Size property on ExecuteSQL is not set to the default of zero or the PostgreSQL driver will try to fetch the whole thing into memory. For 15 GB you could probably use 10000 as the Fetch Size, if that seems slow then 1000 might work better. You can also set Max Rows Per FlowFile to match Fetch Size, then each "chunk" will be handled individually by PutDatabaseRecord, rather than building a single 15 GB FlowFile to send "downstream". The downside is that if some FlowFiles succeed and others fail, you'll need to do something with the failed ones and eventually route them back to PutDatabaseRecord in the hopes they will pass the second time.
Regards, Matt
