ElasticSearch ——（九）搜索API

Routing路由

When executing a search, it will be broadcast to all the index/indices shards (round robin between replicas). Which shards will be searched on can be controlled by providing the routing parameter. For example, when indexing tweets, the routing value can be the user name:
当执行查询时，该查询会被广播到所有的索引分片（在副本间，通过轮询调度算法Round-Robin）。

POST /twitter/_doc?routing=kimchy
{
    "user" : "kimchy",
    "postDate" : "2009-11-15T14:12:12",
    "message" : "trying out Elasticsearch"
}

In such a case, if we want to search only on the tweets for a specific user, we can specify it as the routing, resulting in the search hitting only the relevant shard:

POST /twitter/_search?routing=kimchy
{
    "query": {
        "bool" : {
            "must" : {
                "query_string" : {
                    "query" : "some query string here"
                }
            },
            "filter" : {
                "term" : { "user" : "kimchy" }
            }
        }
    }
}

The routing parameter can be multi valued represented as a comma separated string. This will result in hitting the relevant shards where the routing values match to.

可适应性副本选举

As an alternative to requests being sent to copies of the data in a round robin fashion, you may enable adaptive replica selection. This allows the coordinating node to send the request to the copy deemed “best” based on a number of criteria:

Response time of past requests between the coordinating node and the node containing the copy of the data
Time past search requests took to execute on the node containing the data
The queue size of the search threadpool on the node containing the data
This can be turned on by changing the dynamic cluster setting cluster.routing.use_adaptive_replica_selection from false to true:

PUT /_cluster/settings
{
    "transient": {
        "cluster.routing.use_adaptive_replica_selection": true
    }
}

参考文档

ES官网搜索API