一、需要解决的问题
有的时候我们需要同时执行多个查询，并且需要得到每个单独查询的搜索结果，elasticsearch提供了multi search此需求的支持；
二、elasticsearch multi search简介
elasticsearch提供了multi search api来支持一个请求执行多个查询；
multi search api的请求体使用换行分割的JSON格式；
header\n
body\n
header\n
body\n
multi search返回的结果是responses数组，每个查询对应一个数组元素；每个数组元素都有一个status字段指示查询是否执行成功，如果执行失败则error字段返回错误信息；
每个查询可以通过自己的header设置查询执行的index，也可以是空的JSON对象，这是在URL中指定的index执行查询；
三、数据准备
index以下四个文档
PUT /multi_test/_doc/1
{
"name":"Google Chrome"
}
PUT /multi_test/_doc/2
{
"name":"NotePad"
}
PUT /multi_test/_doc/3
{
"name":"Word"
}
PUT /multi_test/_doc/4
{
"name":"PyCharm"
}
查询查看已经索引的数据
GET /multi_test/_search
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":4,
"max_score":1,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"2",
"_score":1,
"_source":{
"name":"NotePad"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"4",
"_score":1,
"_source":{
"name":"PyCharm"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":1,
"_source":{
"name":"Google Chrome"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"3",
"_score":1,
"_source":{
"name":"Word"
}
}
]
}
}
四、查询测试
我们构造以下四个查询同时执行
POST /multi_test/_msearch
{}
{"query":{"match":{"name":"google"}}}
{}
{"query":{"match":{"name":"nohit"}}}
{}
{"query":{"match":{"name":"word"}}}
{}
{"query":{"bool":{"should":[{"match":{"name":"word"}}, {"match":{"name":"pycharm"}}]}}}
我们可以看到不管查询是否命中结果，都会有一个responses数组元素对应；同时responses数组元素的顺序与查询是一 一对应的；
{
"responses":[
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":0.2876821,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":0.2876821,
"_source":{
"name":"Google Chrome"
}
}
]
},
"status":200
},
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":0,
"max_score":null,
"hits":[
]
},
"status":200
},
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":0.2876821,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"3",
"_score":0.2876821,
"_source":{
"name":"Word"
}
}
]
},
"status":200
},
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":2,
"max_score":0.6931472,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"4",
"_score":0.6931472,
"_source":{
"name":"PyCharm"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"3",
"_score":0.2876821,
"_source":{
"name":"Word"
}
}
]
},
"status":200
}
]
}
五、multi search对search template的支持
multi search api也支持search template；
muti search内联search template查询
POST /multi_test/_msearch/template
{}
{ "source" : "{ \"query\": { \"match\": { \"name\" : \"{{name}}\" } } } }", "params": { "name": "google" } }
{}
{ "source" : "{ \"query\": { \"match_{{template}}\": {} } }", "params": { "template": "all" } }
查询结果为
{
"responses":[
{
"took":0,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":0.2876821,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":0.2876821,
"_source":{
"name":"Google Chrome"
}
}
]
}
},
{
"took":8,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":4,
"max_score":1,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"2",
"_score":1,
"_source":{
"name":"NotePad"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"4",
"_score":1,
"_source":{
"name":"PyCharm"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":1,
"_source":{
"name":"Google Chrome"
}
},
{
"_index":"multi_test",
"_type":"_doc",
"_id":"3",
"_score":1,
"_source":{
"name":"Word"
}
}
]
}
}
]
}
也可以直接新建search template
POST /_scripts/multi_test_name_template/
{
"script":{
"lang":"mustache",
"source":{
"query":{
"bool":{
"should":[
{
"match":{
"name":"{{name}}"
}
},
{
"wildcard":{
"name":"*{{name}}*"
}
}
]
}
}
}
}
}
使用新建的search template进行搜索
POST /multi_test/_msearch/template
{}
{ "id": "multi_test_name_template", "params": { "name": "oo" } }
{}
{ "id": "multi_test_name_template", "params": { "name": "notepad" } }
搜索结果如下
{
"responses":[
{
"took":1,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":1,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":1,
"_source":{
"name":"Google Chrome"
}
}
]
}
},
{
"took":1,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":1.6931472,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"2",
"_score":1.6931472,
"_source":{
"name":"NotePad"
}
}
]
}
}
]
}
在search template中使用嵌套字段作为参数
POST /multi_test/_msearch/template
{}
{ "source" : "{ \"query\": { \"match\": { \"name\" : \"{{person.name}}\" } } } }", "params": { "person":{"name": "google"} } }
搜索结果如下
{
"responses":[
{
"took":3,
"timed_out":false,
"_shards":{
"total":5,
"successful":5,
"skipped":0,
"failed":0
},
"hits":{
"total":1,
"max_score":0.2876821,
"hits":[
{
"_index":"multi_test",
"_type":"_doc",
"_id":"1",
"_score":0.2876821,
"_source":{
"name":"Google Chrome"
}
}
]
}
}
]
}