MongoDB Documentation, Release 3.0.4 If the ntoreturn (page 293) value is 0 , the command did not specify a number of documents to return, as would be the case with a simple find() command with no limit specified. The number of documents the skip() method specified to skip. The number of documents that MongoDB scans in the index (page 481) in order to carry out the operation. In general, if nscanned (page 294) is much higher than nreturned (page 295), the database is scanning many objects to find the target objects. Consider creating an index to improve this. The number of documents that MongoDB scans from the collection in order to carry out the operation. Changed in version 3.0.0: Only appears when using the MMAPv1 storage engine. This field appears with a value of true when an update operation moved one or more documents to a new location on disk. If the operation did not result in a move, this field does not appear. Operations that result in a move take more time than in-place updates and typically occur as a result of document growth. Changed in version 3.0.0: Only appears when using the MMAPv1 storage engine. The number of documents the operation moved on disk. This field appears only if the operation resulted in a move. The field’s implicit value is zero, and the field is present only when non-zero. scanAndOrder (page 294) is a boolean that is true when a query cannot use the ordering in the index to return the requested sorted results; i.e. MongoDB must sort the documents after it receives the documents from a cursor. The field only appears when the value is true . The number of documents deleted by the operation. The number of documents inserted by the operation. New in version 2.6. The number of documents that match the system.profile.query (page 293) condition for the update operation. New in version 2.6. The number of documents modified by the update operation. A boolean that indicates the update operation’s upsert option value. Only appears if upsert is true. The number of index (page 481) keys the update changed in the operation. Changing an index key carries a small performance cost because the database must remove the old key and inserts a new key into the B-tree index. New in version 3.0.0. The number of conflicts encountered during the write operation; e.g. an update operation attempts to modify the same document as another update operation. See also write conflict . system.profile. writeConflicts system.profile. keyUpdates system.profile. upsert system.profile. nModified system.profile. nMatched system.profile. ninserted system.profile. ndeleted system.profile. scanAndOrder system.profile. nmoved system.profile. moved system.profile. nscannedObjects system.profile. nscanned system.profile. ntoskip Chapter 5. Administration 294