SpringData MongoDB - infinite getmore on mongo logs
The lines mean that each [getMore][1] (essentially each iteration on the cursor) is returning 16 documents and that each one is 4MB (the default max batch size limit).  Essentially it is taking a little over 100ms to fetch the documents and return them, and they seem to be around 250KB each.  

Note that the queries are yielding the lock, so they are likely not in memory and are being paged off disk (this is not the only reason that it might yield but it is the most likely).

Here's a quick breakdown of the interesting fields:


nreturned:16 = number of documents returned by the getmore
numYields: 4 = number of times that getmore yielded the lock
locks(micros) r:240837 = the time in microseconds that the read lock was held in total (r), which can be greater than the total execution time
reslen:4265572 = the size of the result in bytes (~4MB)
135ms = the time to complete the getmore operation (100ms is the default threshold for logging slow queries)


If I were to hazard a guess I would think that the { $gte: 5, $lte: 10 } matches an awful lot more data than the { $gte: 10, $lte: 1000000 } criteria, and that all of that data is not fitting into memory, but it is hard to be sure with such a limited snapshot of the activity.