A lot of slow logs are popping up
2017-08-19T01:04:52.623+0800 I COMMAND [conn2059626] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 233ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2057077] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 260ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2057122] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 262ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2059636] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 243ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2057082] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 251ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2059632] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 120ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2057362] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 322ms 2017-08-19T01:04:52.622+0800 I COMMAND [conn2057508] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 223ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2058127] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 317ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2058103] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 238ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2057528] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 198ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2057386] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 248ms 2017-08-19T01:04:52.624+0800 I COMMAND [conn2057131] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 288ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2057957] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 257ms 2017-08-19T01:04:52.623+0800 I COMMAND [conn2058358] command im.$cmd command: saslStart { saslStart: 1, mechanism: "SCRAM-SHA-1", payload: "xxx" } keyUpdates:0 writeConflicts:0 numYields:0 reslen:155 locks:{} protocol:op_query 128ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2058119] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057097] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057993] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057129] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057052] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057409] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2057184] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 13 2ms 2017-08-19T14:09:05.132+0800 I COMMAND [conn2059643] command admin.$cmd command: isMaster { ismaster: 1 } keyUpdates:0 writeConflicts:0 numYields:0 reslen:384 locks:{} protocol:op_query 132ms