Flush APIedit

Flush Requestedit

A FlushRequest can be applied to one or more indices, or even on _all the indices:

FlushRequest request = new FlushRequest("index1"); 
FlushRequest requestMultiple = new FlushRequest("index1", "index2"); 
FlushRequest requestAll = new FlushRequest(); 

Flush one index

Flush multiple indices

Flush all the indices

Optional argumentsedit


Setting IndicesOptions controls how unavailable indices are resolved and how wildcard expressions are expanded


Set the wait_if_ongoing flag to true


Set the force flag to true

Synchronous executionedit

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

FlushResponse flushResponse = client.indices().flush(request, requestOptions);

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 executionedit

Executing a FlushRequest 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 method:

client.indices().flushAsync(request, requestOptions, listener); 

The FlushRequest 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 looks like:

ActionListener<FlushResponse> listener = new ActionListener<FlushResponse>() {
    public void onResponse(FlushResponse flushResponse) {

    public void onFailure(Exception e) {

Called when the execution is successfully completed.

Called when the whole FlushRequest fails.

Flush Responseedit

The returned FlushResponse allows to retrieve information about the executed operation as follows:

int totalShards = flushResponse.getTotalShards(); 
int successfulShards = flushResponse.getSuccessfulShards(); 
int failedShards = flushResponse.getFailedShards(); 
DefaultShardOperationFailedException[] failures = flushResponse.getShardFailures(); 

Total number of shards hit by the flush request

Number of shards where the flush has succeeded

Number of shards where the flush has failed

A list of failures if the operation failed on one or more shards

By default, if the indices were not found, an ElasticsearchException will be thrown:

try {
    FlushRequest request = new FlushRequest("does_not_exist");
    client.indices().flush(request, RequestOptions.DEFAULT);
} catch (ElasticsearchException exception) {
    if (exception.status() == RestStatus.NOT_FOUND) {

Do something if the indices to be flushed were not found