OpenSearch/docs/java-rest/high-level/search/multi-search.asciidoc

[[java-rest-high-multi-search]]
=== Multi-Search API

The `multiSearch` API executes multiple <<java-rest-high-search,`search`>>
requests in a single http request in parallel.

[[java-rest-high-multi-search-request]]
==== Multi-Search Request

The `MultiSearchRequest` is built empty and you add all of the searches that
you wish to execute to it:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[multi-search-request-basic]
--------------------------------------------------
<1> Create an empty `MultiSearchRequest`.
<2> Create an empty `SearchRequest` and populate it just like you
would for a regular <<java-rest-high-search,`search`>>.
<3> Add the `SearchRequest` to the `MultiSearchRequest`.
<4> Build a second `SearchRequest` and add it to the `MultiSearchRequest`.

===== Optional arguments

The `SearchRequest`s inside of `MultiSearchRequest` support all of
<<java-rest-high-search-request-optional,`search`>>'s optional arguments.
For example:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[search-request-indices]
--------------------------------------------------
<1> Restricts the request to an index

[[java-rest-high-multi-search-sync]]
==== Synchronous Execution

The `multiSearch` method executes `MultiSearchRequest`s synchronously:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[multi-search-execute]
--------------------------------------------------

[[java-rest-high-multi-search-async]]
==== Asynchronous Execution

The `multiSearchAsync` method executes `MultiSearchRequest`s asynchronously,
calling the provided `ActionListener` when the response is ready.

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[search-execute-async]
--------------------------------------------------
<1> The `MultiSearchRequest` 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.

A typical listener for `MultiSearchResponse` looks like:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[multi-search-execute-listener]
--------------------------------------------------
<1> Called when the execution is successfully completed.
<2> Called when the whole `SearchRequest` fails.

==== MultiSearchResponse

The `MultiSearchResponse` that is returned by executing the `multiSearch` method contains
a `MultiSearchResponse.Item` for each `SearchRequest` in the
`MultiSearchRequest`. Each `MultiSearchResponse.Item` contains an
exception in `getFailure` if the request failed or a
<<java-rest-high-search-response,`SearchResponse`>> in `getResponse` if
the request succeeded:

["source","java",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{doc-tests}/SearchDocumentationIT.java[multi-search-response]
--------------------------------------------------
<1> The item for the first search.
<2> It succeeded so `getFailure` returns null.
<3> And there is a <<java-rest-high-search-response,`SearchResponse`>> in
`getResponse`.
<4> The item for the second search.