一、需要解決的問題
有的時候我們需要同時執行多個查詢，並且需要得到每個單獨查詢的搜尋結果，elasticsearch提供了multi search此需求的支援；
二、elasticsearch multi search簡介
elasticsearch提供了multi search api來支援一個請求執行多個查詢；
multi search api的請求體使用換行分割的JSON格式；
header\n
body\n
header\n
body\n
multi search返回的結果是responses陣列，每個查詢對應一個陣列元素；每個陣列元素都有一個status欄位指示查詢是否執行成功，如果執行失敗則error欄位返回錯誤資訊；
每個查詢可以透過自己的header設定查詢執行的index，也可以是空的JSON物件，這是在URL中指定的index執行查詢；
三、資料準備
index以下四個文件
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"
}
查詢檢視已經索引的資料
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、查詢測試
我們構造以下四個查詢同時執行
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"}}]}}}
我們可以看到不管查詢是否命中結果，都會有一個responses陣列元素對應；同時responses陣列元素的順序與查詢是一 一對應的；
{
"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對search template的支援
multi search api也支援search template；
muti search內聯search template查詢
POST /multi_test/_msearch/template
{}
{ "source" : "{ \"query\": { \"match\": { \"name\" : \"{{name}}\" } } } }", "params": { "name": "google" } }
{}
{ "source" : "{ \"query\": { \"match_{{template}}\": {} } }", "params": { "template": "all" } }
查詢結果為
{
"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進行搜尋
POST /multi_test/_msearch/template
{}
{ "id": "multi_test_name_template", "params": { "name": "oo" } }
{}
{ "id": "multi_test_name_template", "params": { "name": "notepad" } }
搜尋結果如下
{
"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中使用巢狀欄位作為引數
POST /multi_test/_msearch/template
{}
{ "source" : "{ \"query\": { \"match\": { \"name\" : \"{{person.name}}\" } } } }", "params": { "person":{"name": "google"} } }
搜尋結果如下
{
"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"
}
}
]
}
}
]
}