Can you check to see if your queue was building during the time of Error Code -3? What you’re describing is a hotkey situation, in which case you should either see a hotkey exception or accumulation of requests transaction queue.
http://www.aerospike.com/docs/reference/serverlogmessages/
Depending on your server version, you need to look for a different message… Pre 3.9 - look for the number right after “q”: trans_in_progress: wr 23 prox 0 wait 0 ::: q 1 ::: bq 0 ::: iq 0 ::: dq 0 : fds - proto (17, 2699692, 2699675) : hb (2, 3, 1) : fab (30, 44, 14)
Post 3.9 - look for the number right after “tsvc-q” in-progress: tsvc-q 0 info-q 5 nsup-delete-q 10 rw-hash 0 proxy-hash 0 tree-gc-q 0