Multiple collection ACID transactions
Currently we can update multiple documents with one query if all documents belong to the same collection as shown below;
dB.collection.bulkWrite([ query1, query2, query3, query4 ])
This feature is wonderful but it is paramount if mongodb can enable us to use this query or something similar to update multiple documents from different collections with the one query instead of having to send and await each query one at a time as is currently the case.
The truth is, mongodb only needs to enable this feature of being able to update multiple documents with one query from different collections and then it will certainly be superior to the SQL databases and will get much more market share.