237 lines
10 KiB
Plaintext
237 lines
10 KiB
Plaintext
[role="xpack"]
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[testenv="basic"]
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[[async-search]]
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=== Async search
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The async search API let you asynchronously execute a
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search request, monitor its progress, and retrieve partial results
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as they become available.
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[[submit-async-search]]
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==== Submit async search API
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Executes a search request asynchronously. It accepts the same
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parameters and request body as the <<search-search,search API>>.
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[source,console,id=submit-async-search-date-histogram-example]
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--------------------------------------------------
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POST /sales*/_async_search?size=0
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{
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"sort": [
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{ "date": { "order": "asc" } }
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],
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"aggs": {
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"sale_date": {
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"date_histogram": {
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"field": "date",
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"calendar_interval": "1d"
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}
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}
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}
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}
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--------------------------------------------------
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// TEST[setup:sales]
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// TEST[s/size=0/size=0&wait_for_completion_timeout=10s&keep_on_completion=true/]
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The response contains an identifier of the search being executed.
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You can use this ID to later retrieve the search's final results.
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The currently available search
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results are returned as part of the <<search-api-response-body,`response`>> object.
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[source,console-result]
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--------------------------------------------------
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{
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"id" : "FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=", <1>
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"is_partial" : true, <2>
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"is_running" : true, <3>
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"start_time_in_millis" : 1583945890986,
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"expiration_time_in_millis" : 1584377890986,
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"response" : {
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"took" : 1122,
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"timed_out" : false,
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"num_reduce_phases" : 0,
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"_shards" : {
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"total" : 562, <4>
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"successful" : 3, <5>
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"skipped" : 0,
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"failed" : 0
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},
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"hits" : {
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"total" : {
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"value" : 157483, <6>
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"relation" : "gte"
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},
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"max_score" : null,
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"hits" : [ ]
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}
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}
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}
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--------------------------------------------------
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// TESTRESPONSE[s/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=/$body.id/]
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// TESTRESPONSE[s/"is_partial" : true/"is_partial": $body.is_partial/]
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// TESTRESPONSE[s/"is_running" : true/"is_running": $body.is_running/]
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// TESTRESPONSE[s/1583945890986/$body.start_time_in_millis/]
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// TESTRESPONSE[s/1584377890986/$body.expiration_time_in_millis/]
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// TESTRESPONSE[s/"took" : 1122/"took": $body.response.took/]
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// TESTRESPONSE[s/"num_reduce_phases" : 0,//]
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// TESTRESPONSE[s/"total" : 562/"total": $body.response._shards.total/]
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// TESTRESPONSE[s/"successful" : 3/"successful": $body.response._shards.successful/]
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// TESTRESPONSE[s/"value" : 157483/"value": $body.response.hits.total.value/]
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// TESTRESPONSE[s/"relation" : "gte"/"relation": $body.response.hits.total.relation/]
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// TESTRESPONSE[s/"hits" : \[ \]\n\s\s\s\s\}/"hits" : \[\]},"aggregations": $body.response.aggregations/]
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<1> Identifier of the async search that can be used to monitor its progress,
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retrieve its results, and/or delete it
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<2> When the query is no longer running, indicates whether the search failed
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or was successfully completed on all shards. While the query is being
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executed, `is_partial` is always set to `true`
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<3> Whether the search is still being executed or it has completed
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<4> How many shards the search will be executed on, overall
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<5> How many shards have successfully completed the search
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<6> How many documents are currently matching the query, which belong to the
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shards that have already completed the search
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NOTE: Although the query is no longer running, hence `is_running` is set to
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`false`, results may be partial. That happens in case the search failed after
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some shards returned their results, or when the node that is coordinating the
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async search dies.
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It is possible to block and wait until the search is completed up to a certain
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timeout by providing the `wait_for_completion_timeout` parameter, which
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defaults to `1` second. When the async search completes within such timeout,
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the response won't include the ID as the results are not stored in the cluster.
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The `keep_on_completion` parameter, which defaults to `false`, can be set to
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`true` to request that results are stored for later retrieval also when the
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search completes within the `wait_for_completion_timeout`.
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You can also specify how long the async search needs to be
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available through the `keep_alive` parameter, which defaults to `5d` (five days).
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Ongoing async searches and any saved search results are deleted after this
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period.
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NOTE: When the primary sort of the results is an indexed field, shards get
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sorted based on minimum and maximum value that they hold for that field,
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hence partial results become available following the sort criteria that
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was requested.
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The submit async search API supports the same <<search-search-api-query-params,parameters>>
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as the search API, though some have different default values:
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* `batched_reduce_size` defaults to `5`: this affects how often partial results
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become available, which happens whenever shard results are reduced. A partial
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reduction is performed every time the coordinating node has received a certain
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number of new shard responses (`5` by default).
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* `request_cache` defaults to `true`
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* `pre_filter_shard_size` defaults to `1` and cannot be changed: this is to
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enforce the execution of a pre-filter roundtrip to retrieve statistics from
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each shard so that the ones that surely don't hold any document matching the
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query get skipped.
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* `ccs_minimize_roundtrips` defaults to `false`, which is also the only
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supported value
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WARNING: Async search does not support <<scroll-search-results,scroll>>
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nor search requests that only include the <<search-suggesters,suggest section>>.
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{ccs} is supported only with <<ccs-min-roundtrips,`ccs_minimize_roundtrips`>>
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set to `false`.
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[[get-async-search]]
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==== Get async search
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The get async search API retrieves the results of a previously submitted
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async search request given its id. If the {es} {security-features} are enabled.
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the access to the results of a specific async search is restricted to the user
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that submitted it in the first place.
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[source,console,id=get-async-search-date-histogram-example]
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--------------------------------------------------
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GET /_async_search/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=
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--------------------------------------------------
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// TEST[continued s/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=/\${body.id}/]
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[source,console-result]
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--------------------------------------------------
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{
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"id" : "FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=",
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"is_partial" : true, <1>
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"is_running" : true, <2>
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"start_time_in_millis" : 1583945890986,
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"expiration_time_in_millis" : 1584377890986, <3>
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"response" : {
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"took" : 12144,
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"timed_out" : false,
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"num_reduce_phases" : 46, <4>
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"_shards" : {
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"total" : 562, <5>
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"successful" : 188,
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"skipped" : 0,
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"failed" : 0
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},
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"hits" : {
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"total" : {
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"value" : 456433,
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"relation" : "eq"
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},
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"max_score" : null,
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"hits" : [ ]
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},
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"aggregations" : { <6>
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"sale_date" : {
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"buckets" : []
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}
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}
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}
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}
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--------------------------------------------------
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// TESTRESPONSE[s/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=/$body.id/]
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// TESTRESPONSE[s/"is_partial" : true/"is_partial" : false/]
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// TESTRESPONSE[s/"is_running" : true/"is_running" : false/]
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// TESTRESPONSE[s/1583945890986/$body.start_time_in_millis/]
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// TESTRESPONSE[s/1584377890986/$body.expiration_time_in_millis/]
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// TESTRESPONSE[s/"took" : 12144/"took": $body.response.took/]
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// TESTRESPONSE[s/"total" : 562/"total": $body.response._shards.total/]
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// TESTRESPONSE[s/"successful" : 188/"successful": $body.response._shards.successful/]
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// TESTRESPONSE[s/"value" : 456433/"value": $body.response.hits.total.value/]
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// TESTRESPONSE[s/"buckets" : \[\]/"buckets": $body.response.aggregations.sale_date.buckets/]
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// TESTRESPONSE[s/"num_reduce_phases" : 46,//]
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<1> When the query is no longer running, indicates whether the search failed
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or was successfully completed on all shards. While the query is being
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executed, `is_partial` is always set to `true`
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<2> Whether the search is still being executed or it has completed
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<3> When the async search will expire
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<4> Indicates how many reductions of the results have been performed. If this
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number increases compared to the last retrieved results, you can expect
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additional results included in the search response
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<5> Indicates how many shards have executed the query. Note that in order for
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shard results to be included in the search response, they need to be reduced
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first.
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<6> Partial aggregations results, coming from the shards that have already
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completed the execution of the query.
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The `wait_for_completion_timeout` parameter can also be provided when calling
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the Get Async Search API, in order to wait for the search to be completed up
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until the provided timeout. Final results will be returned if available before
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the timeout expires, otherwise the currently available results will be
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returned once the timeout expires. By default no timeout is set meaning that
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the currently available results will be returned without any additional wait.
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The `keep_alive` parameter specifies how long the async search should be
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available in the cluster. When not specified, the `keep_alive` set with the
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corresponding submit async request will be used. Otherwise, it is possible to
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override such value and extend the validity of the request. When this period
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expires, the search, if still running, is cancelled. If the search is
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completed, its saved results are deleted.
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[[delete-async-search]]
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==== Delete async search
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You can use the delete async search API to manually delete an async search
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by ID. If the search is still running, the search request will be cancelled.
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Otherwise, the saved search results are deleted.
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[source,console,id=delete-async-search-date-histogram-example]
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--------------------------------------------------
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DELETE /_async_search/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=
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--------------------------------------------------
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// TEST[continued s/FmRldE8zREVEUzA2ZVpUeGs2ejJFUFEaMkZ5QTVrSTZSaVN3WlNFVmtlWHJsdzoxMDc=/\${body.id}/]
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