Search code examples
mongodbspring-data-mongodbjava-10

Check if entity exists in mongo with SpringData throws exception count is not allowed in multi document transaction

I use springData and mongo 4.6. I start a transaction, update one document in one collection and then I need to check if another document in another collection exists.

@Transaction
someService() {
     Object res1 = someService1DocuemntUpdate();
     // It fails here.
     boolean exists = anotherObjectRepository.exists(anotherObjectId);
     if (exists) {
         process(res1);
     }
}

And I get 

com.mongodb.MongoCommandException: Command failed with error 50851 (Location50851): 'Cannot run 'count' in a multi-document transaction.
Solution

  • Existance operation works over count operation. Count has restrictions in multi-document transactions The following doc describes workarounds https://docs.mongodb.com/manual/core/transactions/#count-operation

    The easiest fix is to use findBy.. != null More smarter fix is to write agregation request.