Hi @amardeep2021,
You can’t restrict the fields in REST Get snap unless the API from where are you pulling the data can accept some sort of parameters in which you can specify the names of wanted fields, but that depends on the API.
Do you make also many requests to the API or the API is returning you large number of records with only one request ?
If you make more requests to the API to optimize this a little bit you can try first to group the data in chunks of lets say with 1000 records and pass those chunks one by one in Pipeline Execute, where you will call other pipeline in which you will split the data and make the API call, after the call with mapper you can select only those fields that you need it, and pass it back to the parent pipeline .
Regards,
Viktor
