Adding new index to production collection

Hi Team,
I have one collection in production env. Due to feature enhancements, I am going to add new indices.
Whats the best practice we should follow for this ??
Do I have to clear and re-enter existing data again after creating indexes??
Also I m going to add two new fields in existing production data. Is there any feature mongo atlas support which will make this addition super simple ??

Thanks,
Gheri.

For index creation look at https://docs.mongodb.com/manual/tutorial/build-indexes-on-replica-sets/.

For adding fields I am a big fan of https://www.mongodb.com/blog/post/building-with-patterns-the-document-versioning-pattern.

Thanks for pointing to this.
I think we have already using document versioning pattern so it would be easy for me to update the documents with new fields.
Now we can afford some performance degradation so can i rely on createIndex() to take care of existing data.

Thanks,
Gheri.

Hi Team,
The Reason to update existing records with new fields becuase I would be creating indices on one of the fields and somewhere I had read that there would be performance degradation if some fields are null.
Just wanted to confirm this performance cost??
If its not performance degration in above case, then i can keep these existing records as they are for some time.

Thanks,
Gheri.

Any updates on above query ??