From the missing data sent by you, one can understand that the batch size set is 5000. Therefore, the answer is quite clear. There are 2 events missing to complete the batch. The 4988 events are waiting for the completionnof the batch in the channel temporary storage.

On 9 Dec 2015 04:40, "Zhishan Li" <zhishanlee@gmail.com> wrote:
All,

Dose the HDFS Sink loss data?

Here is metrics from http monitor feature.
"SINK.k1": {
"BatchCompleteCount": "824",
"ConnectionFailedCount": "0",
"EventDrainAttemptCount": "4124988",
"ConnectionCreatedCount": "28",
"Type": "SINK",
"BatchEmptyCount": "0",
"ConnectionClosedCount": "20",
"EventDrainSuccessCount": "4120000",
"StopTime": "0",
"StartTime": "1449490280602",
"BatchUnderflowCount": "0"
},

EventDrainAttemptCount: 4124988 is what HDFS sink received events.
But EventDrainSuccessCount: 4120000 is those events flushed to hdfs. Right?

Where is other events: 4988 ( =4124988 - 4120000) ?

Thanks