Attunity driver for extracting data from Oracle is faster but if you are extracting millions of rows from Oracle and you think it is slower than anticipated, make sure you change the following advanced settings
Right click on Oracle Data Source and click on “Show Advanced Editor…”.
Go to “Component Properties” tab and under “Custom Properties” > “BatchSize”.
The default batch size is 100 which means that as soon as 100 rows are fetched, it will be sent down the pipeline. If you are using cloud environment, sending through pipeline has extra overhead causing performance degradation while fetching millions of rows. Instead, increase the BatchSize value to 10000 and you will feel the performance difference. 10000 is my magic number and worked in all the situations for me but you may have to find your own magic number by experimenting with it