1. A method comprising: receiving an extract, transform and load (ETL) job, the ETL job configured to access a source database that includes data organized into source database table columns and source database table rows; predicting a first resource requirement to execute the ETL job using the source database table in a row representation configured to read all of the source database table columns in a source database table row as a unit; predicting a second resource requirement to execute the ETL job using the source database table in a column representation configured to read at least a subset of the source database table rows in a source database column as a unit; responsive to the first resource requirement being larger than the second resource requirement, converting the source database table to the column representation and executing the ETL job as a column based data transfer ETL job; and responsive to the first resource requirement being less than or equal to the second resource requirement, converting the source database table to the row representation and executing the ETL job as a row based data transfer ETL job.