But even then, you could still split() the big-text by paragraph if you come up with a suitable regular-expression by which to do it.   Really, the answer to this question is, “it’s up to you.”   Perl certainly won’t blink at strings or other data structures that are many megabytes in size, including “paragraphs” which seem to you to be “big.”

OP, if you will give us more details about what you are actually facing, we can step away from this water-cooler and help you.   Details, please.   :-)