To reproduce, you need a replicaset with at least two secondary nodes.
sbt "run mongodb://primary:27017,secondary0:27017,secondary1:27017/dbname"
The test will create a dbname.rmbug2 collection, empty it, and insert 2000 documents.
Then it will list the documents from mongodb to stdout with different ReadPreference:
secondaryPreferred and primaryPreferred.
Expected: should print 2000 documents. Issue: only print 101 or 202 documents.
Output:
|total document inserted: 2000
| total result from Secondary Preferred : 101
| total result from Primary Preferred : 2000