Deprecated in the mongo Shell since v3.2
Starting in v3.2, the $comment operator is deprecated in the mongo shell. In the mongo shell, use cursor.comment() instead.

The $comment meta-operator makes it possible to attach a comment to a query in any context that $query may appear.

Because comments propagate to the profile log, adding a comment can make your profile data easier to interpret and trace.

Use $comment in one of the following ways:

db.collection.find( { <query> } )._addSpecial( "$comment", <comment> )
db.collection.find( { <query> } ).comment( <comment> )
db.collection.find( { $query: { <query> }, $comment: <comment> } )

To attach comments to query expressions in other contexts, such as db.collection.update(), use the $comment query operator instead of the meta-operator.

See also

$comment query operator

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