OpenSearch/docs/java-rest/high-level/document/rethrottle.asciidoc

[[java-rest-high-document-rethrottle]]
=== Rethrottle API

[[java-rest-high-document-rethrottle-request]]
==== Rethrottle Request

A `RethrottleRequest` can be used to change the current throttling on a running
reindex, update-by-query or delete-by-query task or to disable throttling of
the task entirely. It requires the task Id of the task to change.

In its simplest form, you can use it to disable throttling of a running
task using the following:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/CRUDDocumentationIT.java[rethrottle-disable-request]
--------------------------------------------------
<1> Create a `RethrottleRequest` that disables throttling for a specific task id

By providing a `requestsPerSecond` argument, the request will change the
existing task throttling to the specified value:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/CRUDDocumentationIT.java[rethrottle-request]
--------------------------------------------------
<1> Request to change the throttling of a task to 100 requests per second

The rethrottling request can be executed by using one of the three appropriate
methods depending on whether a reindex, update-by-query or delete-by-query task
should be rethrottled:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/CRUDDocumentationIT.java[rethrottle-request-execution]
--------------------------------------------------
<1> Execute reindex rethrottling request
<2> The same for update-by-query
<3> The same for delete-by-query

[[java-rest-high-document-rethrottle-async]]
==== Asynchronous Execution

The asynchronous execution of a rethrottle request requires both the `RethrottleRequest`
instance and an `ActionListener` instance to be passed to the asynchronous
method:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/CRUDDocumentationIT.java[rethrottle-execute-async]
--------------------------------------------------
<1> Execute reindex rethrottling asynchronously
<2> The same for update-by-query
<3> The same for delete-by-query

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. A typical listener looks like this:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/CRUDDocumentationIT.java[rethrottle-request-async-listener]
--------------------------------------------------
<1> Code executed when the request is successfully completed
<2> Code executed when the request fails with an exception

[[java-rest-high-document-retrottle-response]]
==== Rethrottle Response

Rethrottling returns the task that has been rethrottled in the form of a 
`ListTasksResponse`. The structure of this response object is described in detail 
in <<java-rest-high-cluster-list-tasks-response,this section>>.