Flush Job API

The Flush Job API provides the ability to flush a machine learning job’s datafeed in the cluster. It accepts a FlushJobRequest object and responds with a FlushJobResponse object.

Flush Job Request

A FlushJobRequest object gets created with an existing non-null jobId. All other fields are optional for the request.

FlushJobRequest flushJobRequest = new FlushJobRequest("flushing-my-first-machine-learning-job"); 

Constructing a new request referencing an existing jobId

Optional Arguments

The following arguments are optional.

flushJobRequest.setCalcInterim(true); 
flushJobRequest.setAdvanceTime("2018-08-31T16:35:07+00:00"); 
flushJobRequest.setStart("2018-08-31T16:35:17+00:00"); 
flushJobRequest.setEnd("2018-08-31T16:35:27+00:00"); 
flushJobRequest.setSkipTime("2018-08-31T16:35:00+00:00"); 

Set request to calculate the interim results

Set the advanced time to flush to the particular time value

Set the start time for the range of buckets on which to calculate the interim results (requires calc_interim to be true)

Set the end time for the range of buckets on which to calculate interim results (requires calc_interim to be true)

Set the skip time to skip a particular time value

Flush Job Response

A FlushJobResponse contains an acknowledgement and an optional end date for the last finalized bucket

boolean isFlushed = flushJobResponse.isFlushed(); 
Date lastFinalizedBucketEnd = flushJobResponse.getLastFinalizedBucketEnd(); 

isFlushed() indicates if the job was successfully flushed or not.

getLastFinalizedBucketEnd() provides the timestamp (in milliseconds-since-the-epoch) of the end of the last bucket that was processed.

Synchronous Execution

When executing a FlushJobRequest in the following manner, the client waits for the FlushJobResponse to be returned before continuing with code execution:

FlushJobResponse flushJobResponse = client.machineLearning().flushJob(flushJobRequest, RequestOptions.DEFAULT);

Synchronous calls may throw an IOException in case of either failing to parse the REST response in the high-level REST client, the request times out or similar cases where there is no response coming back from the server.

In cases where the server returns a 4xx or 5xx error code, the high-level client tries to parse the response body error details instead and then throws a generic ElasticsearchException and adds the original ResponseException as a suppressed exception to it.

Asynchronous Execution

Executing a FlushJobRequest can also be done in an asynchronous fashion so that the client can return directly. Users need to specify how the response or potential failures will be handled by passing the request and a listener to the asynchronous flush-job method:

client.machineLearning().flushJobAsync(flushJobRequest, RequestOptions.DEFAULT, listener); 

The FlushJobRequest to execute and the ActionListener to use when the execution completes

The asynchronous method does not block and returns immediately. Once it is completed the ActionListener is called back using the onResponse method if the execution successfully completed or using the onFailure method if it failed. Failure scenarios and expected exceptions are the same as in the synchronous execution case.

A typical listener for flush-job looks like:

ActionListener<FlushJobResponse> listener = new ActionListener<FlushJobResponse>() {
    @Override
    public void onResponse(FlushJobResponse FlushJobResponse) {
        
    }

    @Override
    public void onFailure(Exception e) {
        
    }
};

Called when the execution is successfully completed.

Called when the whole FlushJobRequest fails.