Multi-Get API
editMulti-Get API
editThe multiGet
API executes multiple get
requests in a single http request in parallel.
Multi-Get Request
editA MultiGetRequest
is built empty and you add `MultiGetRequest.Item`s to
configure what to fetch:
Optional arguments
editmultiGet
supports the same optional arguments that the
get
API supports.
You can set most of these on the Item
:
request.add(new MultiGetRequest.Item("index", "type", "example_id") .fetchSourceContext(FetchSourceContext.DO_NOT_FETCH_SOURCE));
String[] includes = new String[] {"foo", "*r"}; String[] excludes = Strings.EMPTY_ARRAY; FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes); request.add(new MultiGetRequest.Item("index", "type", "example_id") .fetchSourceContext(fetchSourceContext));
String[] includes = Strings.EMPTY_ARRAY; String[] excludes = new String[] {"foo", "*r"}; FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes); request.add(new MultiGetRequest.Item("index", "type", "example_id") .fetchSourceContext(fetchSourceContext));
request.add(new MultiGetRequest.Item("index", "type", "example_id") .storedFields("foo")); MultiGetResponse response = client.multiGet(request); MultiGetItemResponse item = response.getResponses()[0]; String value = item.getResponse().getField("foo").getValue();
Configure retrieval for specific stored fields (requires fields to be stored separately in the mappings) |
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Retrieve the |
request.add(new MultiGetRequest.Item("index", "type", "with_routing") .routing("some_routing")); request.add(new MultiGetRequest.Item("index", "type", "with_parent") .parent("some_parent")); request.add(new MultiGetRequest.Item("index", "type", "with_version") .versionType(VersionType.EXTERNAL) .version(10123L));
preference
,
realtime
and
refresh
can be set on the main request but
not on any items:
Synchronous Execution
editAfter building the MultiGetRequest
you can execute it synchronously with
multiGet
:
MultiGetResponse response = client.multiGet(request);
Asynchronous Execution
editThe asynchronous execution of a multi get request requires both the
MultiGetRequest
instance and an ActionListener
instance to be passed to
the asynchronous method:
The asynchronous method does not block and returns immediately. Once the
request 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 MultiGetResponse
looks like:
Multi Get Response
editThe returned MultiGetResponse
contains a list of MultiGetItemResponse`s in
`getResponses
in the same order that they were requested.
MultiGetItemResponse
contains either a
GetResponse
if the get succeeded
or a MultiGetResponse.Failure
if it failed. A success looks just like a
normal GetResponse
.
MultiGetItemResponse firstItem = response.getResponses()[0]; assertNull(firstItem.getFailure()); GetResponse firstGet = firstItem.getResponse(); String index = firstItem.getIndex(); String type = firstItem.getType(); String id = firstItem.getId(); if (firstGet.isExists()) { long version = firstGet.getVersion(); String sourceAsString = firstGet.getSourceAsString(); Map<String, Object> sourceAsMap = firstGet.getSourceAsMap(); byte[] sourceAsBytes = firstGet.getSourceAsBytes(); } else { }
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Retrieve the document as a |
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Retrieve the document as a |
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Retrieve the document as a |
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Handle the scenario where the document was not found. Note that although
the returned response has |
When one of the subrequests as performed against an index that does not exist
getFailure
will contain an exception:
assertNull(missingIndexItem.getResponse()); Exception e = missingIndexItem.getFailure().getFailure(); ElasticsearchException ee = (ElasticsearchException) e; // TODO status is broken! fix in a followup // assertEquals(RestStatus.NOT_FOUND, ee.status()); assertThat(e.getMessage(), containsString("reason=no such index"));
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That |
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In case a specific document version has been requested, and the existing document has a different version number, a version conflict is raised:
MultiGetRequest request = new MultiGetRequest(); request.add(new MultiGetRequest.Item("index", "type", "example_id") .version(1000L)); MultiGetResponse response = client.multiGet(request); MultiGetItemResponse item = response.getResponses()[0]; assertNull(item.getResponse()); Exception e = item.getFailure().getFailure(); ElasticsearchException ee = (ElasticsearchException) e; // TODO status is broken! fix in a followup // assertEquals(RestStatus.CONFLICT, ee.status()); assertThat(e.getMessage(), containsString("version conflict, current version [1] is " + "different than the one provided [1000]"));