Multiple object body requests for searches on comment and delete operations are extremely slow

[#1]

I am trying to do a multiple object search for almost 50 records based on the comment value
(expectation is to search for upt 1000 records in a single request object). The search takes long time. The searched records need to be deleted and the delete operation also takes a long time. Is there any other quciker way to fasten the search and delete process. 

[#2]

That is going to be a slow process unfortunately.  I suspect the comment field is not indexed, so it woudl need to do a text search through them all to get results.