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This commit changes the default out-of-the-box configuration for the number of shards from five to one. We think this will help address a common problem of oversharding. For users with time-based indices that need a different default, this can be managed with index templates. For users with non-time-based indices that find they need to re-shard with the split API in place they no longer need to resort only to reindexing. Since this has the impact of changing the default number of shards used in REST tests, we want to ensure that we still have coverage for issues that could arise from multiple shards. As such, we randomize (rarely) the default number of shards in REST tests to two. This is managed via a global index template. However, some tests check the templates that are in the cluster state during the test. Since this template is randomly there, we need a way for tests to skip adding the template used to set the number of shards to two. For this we add the default_shards feature skip. To avoid having to write our docs in a complicated way because sometimes they might be behind one shard, and sometimes they might be behind two shards we apply the default_shards feature skip to all docs tests. That is, these tests will always run with the default number of shards (one).
110 lines
3.2 KiB
Plaintext
110 lines
3.2 KiB
Plaintext
[[search-count]]
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== Count API
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The count API allows to easily execute a query and get the number of
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matches for that query. It can be executed across one or more indices
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and across one or more types. The query can either be provided using a
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simple query string as a parameter, or using the
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<<query-dsl,Query DSL>> defined within the request
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body. Here is an example:
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[source,js]
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--------------------------------------------------
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PUT /twitter/_doc/1?refresh
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{
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"user": "kimchy"
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}
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GET /twitter/_doc/_count?q=user:kimchy
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GET /twitter/_doc/_count
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{
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"query" : {
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"term" : { "user" : "kimchy" }
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}
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}
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--------------------------------------------------
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//CONSOLE
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NOTE: The query being sent in the body must be nested in a `query` key, same as
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the <<search-search,search api>> works
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Both examples above do the same thing, which is count the number of
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tweets from the `twitter` index for a certain user. The result is:
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[source,js]
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--------------------------------------------------
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{
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"count" : 1,
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"_shards" : {
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"total" : 1,
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"successful" : 1,
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"skipped" : 0,
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"failed" : 0
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}
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}
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--------------------------------------------------
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// TESTRESPONSE
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The query is optional, and when not provided, it will use `match_all` to
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count all the docs.
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[float]
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=== Multi index, Multi type
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The count API can be applied to <<search-multi-index-type,multiple types in multiple indices>>.
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[float]
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=== Request Parameters
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When executing count using the query parameter `q`, the query passed is
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a query string using Lucene query parser. There are additional
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parameters that can be passed:
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[cols="<,<",options="header",]
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|=======================================================================
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|Name |Description
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|`df` |The default field to use when no field prefix is defined within the
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query.
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|`analyzer` |The analyzer name to be used when analyzing the query string.
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|`default_operator` |The default operator to be used, can be `AND` or
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`OR`. Defaults to `OR`.
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|`lenient` |If set to true will cause format based failures (like
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providing text to a numeric field) to be ignored. Defaults to false.
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|`analyze_wildcard` |Should wildcard and prefix queries be analyzed or
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not. Defaults to `false`.
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|`terminate_after` |The maximum count for each shard, upon
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reaching which the query execution will terminate early.
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If set, the response will have a boolean field `terminated_early` to
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indicate whether the query execution has actually terminated_early.
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Defaults to no terminate_after.
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|=======================================================================
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[float]
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=== Request Body
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The count can use the <<query-dsl,Query DSL>> within
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its body in order to express the query that should be executed. The body
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content can also be passed as a REST parameter named `source`.
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Both HTTP GET and HTTP POST can be used to execute count with body.
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Since not all clients support GET with body, POST is allowed as well.
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[float]
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=== Distributed
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The count operation is broadcast across all shards. For each shard id
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group, a replica is chosen and executed against it. This means that
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replicas increase the scalability of count.
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[float]
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=== Routing
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The routing value (a comma separated list of the routing values) can be
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specified to control which shards the count request will be executed on.
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