Is mongodb slower to query multiple fields than a single field?

  mongodb, question

For example, a query condition

{hash:'abc', status:0, classid:'cdf'}

If I combine these three conditions into one field, for example

new_key:md5(hash+status+classid)

Every time I go to check

{new_key:new_key}

Will this be faster than the above query?

Although I have now made a composite index for the first query.

This method will reduce the cost of database resources, but the order of database retrieval is to first retrieve the index and then retrieve the fields. The speed depends on the establishment of your index.