Validating Rollup index

How to validate if the rolled up index has all the data from the source index. I have a rollup job scheduled to run everyday. I will be deleting the source index after the rollup schedule is done, I want to know if the rolled up index has all the data before deleting the source index.

Being a rollup, that will depend on what you have configured. The concept of it is to be a summary after all, which can never be all the data.

Let me rephrase it, Say I have 10 fields and 300 documents in the source index, I'm rolling up 5 fields, how to validate that I have all the 300 documents in the rolled up index too?

Can you share your rollup config?