DOCSP-28304-drop-qe-metadata-collections (#4239)

* Added guidance around dropping metadata collections

* Added guidance around dropping metadata collections

* Wording clarification

* Wording clarification

Author: nvillahermosa-mdb

source/core/queryable-encryption/fundamentals/manage-collections.txt

@@ -65,6 +65,16 @@ MongoDB updates the metadata collections to maintain an index
 that enables querying. The field becomes an "indexed field". This
 comes at a cost in storage and write speed for every such field.
 
+Dropping Encrypted Collections
+------------------------------
+
+When you drop an encrypted collection, drop the associated
+metadata collections ``enxcol_.<collectionName>.esc`` and
+``enxcol_.<collectionName>.ecoc`` immediately afterwards. Otherwise,
+re-creating the collection with the same name puts the metadata
+collections in a conflicted state that consumes excess storage space and
+degrades CRUD performance.
+
 Storage Costs
 -------------