Abhijit,
There are no specific features that are activated when a data load crosses a specific threshold/size, but it should be noted that the Console Data Loader is specifically designed for scalability. In other words, you will not see a linear increase in the length of time required for a job to execute as the number of records/entities in the job increases. The Data Loader will analyze the job size and complexity during pre-processing and allocate resources accordingly. That said, we do often recommend as a best practice that giant data loads be "chunked" into smaller batches, just as a way to reduce the possibility of a point of failure impacting the entire load. In your case, for instance, it might make sense to break the 300M record job into, say, 6 jobs at 50M records apiece.
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Best regards,
Jack Hain
Senior Product Manager
Reltio, Inc.
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