(转)通过HTTP RESTful API 操作elasticsearch搜索数据

其他 2018-05-12 22:37:08 阅读次数: 2

样例数据集

这是编造的JSON格式银行客户账号信息文档，文档schema如下： 
{ 
“account_number”: 0, 
“balance”: 16623, 
“firstname”: “Bradshaw”, 
“lastname”: “Mckenzie”, 
“age”: 29, 
“gender”: “F”, 
“address”: “244 Columbus Place”, 
“employer”: “Euron”, 
“email”: “[email protected]”, 
“city”: “Hobucken”, 
“state”: “CO” 
} 
这些数据可以通过www.json-generator.com网站生成

加载样例数据集

下载样例数据集链接 
解压数据到指定目录，然后加载到elasticsearch集群

绝对路径：
curl -XPOST 'localhost:9200/bank/account/_bulk?pretty' --data-binary "@/home/cluster/apps/elasticsearch/elasticsearch-1.7.2/test/accounts.json" 相对路径： curl -XPOST 'localhost:9200/bank/account/_bulk?pretty' --data-binary "@test/accounts.json"
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curl 'localhost:9200/_cat/indices?v'
结果：
health status index              pri rep docs.count docs.deleted store.size pri.store.size 
yellow open   bank                 5   1 1000 0 417.1kb 417.1kb
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上面结果，说明我们成功bulk 1000个文档到bank索引中了

搜索数据API

有两种方式：一种方式是通过 REST 请求 URI ，发送搜索参数；另一种是通过REST 请求体，发送搜索参数。而请求体允许你包含更容易表达和可阅读的JSON格式。

  • 通过 REST 请求 URI
curl 'localhost:9200/bank/_search?q=*&pretty'

结果：
{
  "took" : 63,
  "timed_out" : false,
  "_shards" : { "total" : 5, "successful" : 5, "failed" : 0 }, "hits" : { "total" : 1000, "max_score" : 1.0, "hits" : [ { "_index" : "bank", "_type" : "account", "_id" : "1", "_score" : 1.0, "_source" : {"account_number":1,"balance":39225,"firstname":"Amber","lastname":"Duke","age":32,"gender":"M","address":"880 Holmes Lane","employer":"Pyrami","email":"amberduke@pyrami.com","city":"Brogan","state":"IL"} }, { "_index" : "bank", "_type" : "account", "_id" : "6", "_score" : 1.0, "_source" : {"account_number":6,"balance":5686,"firstname":"Hattie","lastname":"Bond","age":36,"gender":"M","address":"671 Bristol Street","employer":"Netagy","email":"hattiebond@netagy.com","city":"Dante","state":"TN"} }, { "_index" : "bank", "_type" : "account",
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q=*，参数告诉elasticsearch，在bank索引中匹配所有的文档 
pretty，参数告诉elasticsearch，返回形式打印JSON结果

  • 通过REST 请求体：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_all": {} }
}'

结果：
{
  "took" : 26, "timed_out" : false, "_shards" : { "total" : 5, "successful" : 5, "failed" : 0 }, "hits" : { "total" : 1000, "max_score" : 1.0, "hits" : [ { "_index" : "bank", "_type" : "account", "_id" : "1", "_score" : 1.0, "_source" : {"account_number":1,"balance":39225,"firstname":"Amber","lastname":"Duke","age":32,"gender":"M","address":"880 Holmes Lane","employer":"Pyrami","email":"[email protected]","city":"Brogan","state":"IL"} }, { "_index" : "bank", "_type" : "account", "_id" : "6", "_score" : 1.0, "_source" : {"account_number":6,"balance":5686,"firstname":"Hattie","lastname":"Bond","age":36,"gender":"M","address":"671 Bristol Street","employer":"Netagy","email":"[email protected]","city":"Dante","state":"TN"} }, { "_index" : "bank", "_type" : "account", "_id" : "13",
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与第一种方式不同是在URI中替代传递q=*，使用POST方式提交，请求体包含JSON格式搜索

介绍查询语言

elasticsearch提供JSON格式领域特定语言执行查询。可参考Query DSL。

{
  "query": { "match_all": {} }
}
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query：告诉我们定义查询 
match_all：运行简单类型查询指定索引中的所有文档

除了指定查询参数，还可以指定其他参数来影响最终的结果。

  • match_all & 只返回第一个文档：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_all": {} },
  "size": 1 }' 结果： { "took" : 2, "timed_out" : false, "_shards" : { "total" : 5, "successful" : 5, "failed" : 0 }, "hits" : { "total" : 1000, "max_score" : 1.0, "hits" : [ { "_index" : "bank", "_type" : "account", "_id" : "4", "_score" : 1.0, "_source":{"account_number":4,"balance":27658,"firstname":"Rodriquez","lastname":"Flores","age":31,"gender":"F","address":"986 Wyckoff Avenue","employer":"Tourmania","email":"[email protected]","city":"Eastvale","state":"HI"} } ] } }
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如果不指定size，默认是返回10条文档信息

  • match_all & 返回11到20个文档信息
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_all": {} },
  "from": 10, "size": 10 }'
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from：指定文档索引从哪里开始，默认从0开始 
size：从from开始，返回多个文档 
这feature在实现分页查询很有用

  • match_all and 根据account balance 降序排序 & 返回10个文档（默认10个）
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_all": {} },
  "sort": { "balance": { "order": "desc" } } }'
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执行搜索

默认的，我们搜索返回完整的JSON文档。而source（_source字段搜索点击量）。如果我们不想返回完整的JSON文档，我们可以使用source返回指定字段。

  • 返回 account_number and balance：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_all": {} },
  "_source": ["account_number", "balance"] }'
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这样操作有点类似于SQL SELECT FROM field lis

match 查询，可作为基本字段搜索查询 
- 返回 account_number=20:

curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match": { "account_number": 20 } } }'
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  • 返回 address=mill：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match": { "address": "mill" } } }'
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  • 返回 address=mill or address=lane：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match": { "address": "mill lane" } } }'
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  • 返回 短语匹配 address=mill lane：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": { "match_phrase": { "address": "mill lane" } } }'
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布尔值(bool)查询

  • 返回 匹配address=mill & address=lane：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": {
    "bool": {
      "must": [ { "match": { "address": "mill" } }, { "match": { "address": "lane" } } ] } } }'
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must:要求所有条件都要满足（类似于&&）

  • 返回 匹配address=mill or address=lane：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": {
    "bool": {
      "should": [ { "match": { "address": "mill" } }, { "match": { "address": "lane" } } ] } } }'
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should：任何一个满足就可以（类似于||）

  • 返回 不匹配address=mill & address=lane：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": {
    "bool": {
      "must_not": [ { "match": { "address": "mill" } }, { "match": { "address": "lane" } } ] } } }'
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must_not:所有条件都不能满足（类似于! (&&)）

  • 返回 age=40 & state!=ID
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": {
    "bool": {
      "must": [ { "match": { "age": "40" } } ], "must_not": [ { "match": { "state": "ID" } } ] } } }'
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执行过滤器

文档中score(_score字段是搜索结果)。score是一个数字型的，是一种相对方法匹配查询文档结果。分数越高，搜索关键字与该文档相关性越高；越低，搜索关键字与该文档相关性越低。

在elasticsearch中所有的搜索都会触发相关性分数计算。如果我们不使用相关性分数计算，那要使用另一种查询能力，构建过滤器。

过滤器是类似于查询的概念,除了得以优化,更快的执行速度的两个主要原因: 
1. 过滤器不计算得分，所以他们比执行查询的速度 
2. 过滤器可缓存在内存中，允许重复搜索

为了便于理解过滤器，先介绍过滤器搜索(like match_all, match, bool, etc.)，可以与其他的普通查询搜索组合一个过滤器。 
range filter,允许我们通过一个范围值来过滤文档，一般用于数字或日期过滤

使用过滤器搜索返回 balances[ 20000,30000]。换句话说，balance>=20000 && balance<=30000

curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "query": {
    "filtered": {
      "query": { "match_all": {} }, "filter": { "range": { "balance": { "gte": 20000, "lte": 30000 } } } } } }' 结果： { "took" : 3, "timed_out" : false, "_shards" : { "total" : 5, "successful" : 5, "failed" : 0 }, "hits" : { "total" : 217, "max_score" : 1.0, "hits" : [ { "_index" : "bank", "_type" : "account", "_id" : "4", "_score" : 1.0, "_source":{"account_number":4,"balance":27658,"firstname":"Rodriquez","lastname":"Flores","age":31,"gender":"F","address":"986 Wyckoff Avenue","employer":"Tourmania","email":"[email protected]","city":"Eastvale","state":"HI"} }, { "_index" : "bank", "_type" : "account", "_id" : "9", "_score" : 1.0, "_source":{"account_number":9,"balance":24776,"firstname":"Opal","lastname":"Meadows","age":39,"gender":"M","address":"963 Neptune Avenue","employer":"Cedward","email":"[email protected]","city":"Olney","state":"OH"} }, { "_index" : "bank", "_type" : "account", "_id" : "11", "_score" : 1.0, "_source":{"account_number":11,"balance":20203,"firstname":"Jenkins","lastname":"Haney","age":20,"gender":"M","address":"740 Ferry Place","employer":"Qimonk","email":"[email protected]","city":"Steinhatchee","state":"GA"} }, { "_index" : "bank", "_type" : "account", "_id" : "42", "_score" : 1.0, "_source":{"account_number":42,"balance":21137,"firstname":"Harding","lastname":"Hobbs","age":26,"gender":"F","address":"474 Ridgewood Place","employer":"Xth","email":"[email protected]","city":"Heil","state":"ND"} }, { "_index" : "bank", "_type" : "account", "_id" : "54", "_score" : 1.0, "_source":{"account_number":54,"balance":23406,"firstname":"Angel","lastname":"Mann","age":22,"gender":"F","address":"229 Ferris Street","employer":"Amtas","email":"[email protected]","city":"Calverton","state":"WA"} }, { "_index" : "bank", "_type" : "account", "_id" : "66", "_score" : 1.0, "_source":{"account_number":66,"balance":25939,"firstname":"Franks","lastname":"Salinas","age":28,"gender":"M","address":"437 Hamilton Walk","employer":"Cowtown","email":"[email protected]","city":"Chase","state":"VT"} }, { "_index" : "bank", "_type" : "account", "_id" : "92", "_score" : 1.0, "_source":{"account_number":92,"balance":26753,"firstname":"Gay","lastname":"Brewer","age":34,"gender":"M","address":"369 Ditmars Street","employer":"Savvy","email":"[email protected]","city":"Moquino","state":"HI"} }, { "_index" : "bank", "_type" : "account", "_id" : "100", "_score" : 1.0, "_source":{"account_number":100,"balance":29869,"firstname":"Madden","lastname":"Woods","age":32,"gender":"F","address":"696 Ryder Avenue","employer":"Slumberia","email":"[email protected]","city":"Deercroft","state":"ME"} }, { "_index" : "bank", "_type" : "account", "_id" : "105", "_score" : 1.0,
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过滤查询包含match_all查询(查询部分)和一系列过滤(过滤部分)。可以代替任何其他查询到查询部分以及其他过滤器过滤部分。在上述情况下,过滤器范围智能，因为文档落入range所有匹配“平等”,即。比另一个更相关,没有文档。

一般情况，最明智的方式决定是否使用filter or query，就看你是否关心相关性分数。如果相关性不重要，那就使用filter，否则就使用query。 
queries and filters很类似于关系型数据库中的 “SELECT WHERE clause”

执行聚合

聚合提供从你的数据中分组和提取统计能力。 
类似于关系型数据中的SQL GROUP BY和SQL 聚合函数。

在Elasticsearch,你有能力执行搜索返回命中结果,同时拆分命中结果，然后统一返回结果。当你使用简单的API运行搜索和多个聚合，然后返回所有结果避免网络带宽过大的情况是高效的。

  • 根据state分组，降序统计top 10 state
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "size": 0,
  "aggs": { "group_by_state": { "terms": { "field": "state" } } } }' 结果： "hits" : { "total" : 1000, "max_score" : 0.0, "hits" : [ ] }, "aggregations" : { "group_by_state" : { "buckets" : [ { "key" : "al", "doc_count" : 21 }, { "key" : "tx", "doc_count" : 17 }, { "key" : "id", "doc_count" : 15 }, { "key" : "ma", "doc_count" : 15 }, { "key" : "md", "doc_count" : 15 }, { "key" : "pa", "doc_count" : 15 }, { "key" : "dc", "doc_count" : 14 }, { "key" : "me", "doc_count" : 14 }, { "key" : "mo", "doc_count" : 14 }, { "key" : "nd", "doc_count" : 14 } ] } } }
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类似于关系型数据库

SELECT state, COUNT(*) FROM bank GROUP BY state ORDER BY COUNT(*) DESC
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size=0 不是展示搜索结果命中数，因为我只是想要看聚合结果

  • 根据state计算账户平均balance，降序统计top 10 state
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "size": 0,
  "aggs": { "group_by_state": { "terms": { "field": "state" }, "aggs": { "average_balance": { "avg": { "field": "balance" } } } } } }'
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注意嵌套average_balance聚合group_by_state内聚合。这是一个常见的模式,所有的聚合。您可以嵌套内聚合聚合任意提取旋转汇总时,你需要从你的数据。

  • 降序排序平均 balance：
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "size": 0,
  "aggs": { "group_by_state": { "terms": { "field": "state", "order": { "average_balance": "desc" } }, "aggs": { "average_balance": { "avg": { "field": "balance" } } } } } }'
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  • 聚合年龄分区间(ages 20-29, 30-39, and 40-49),聚合性别，最后平均balance 展示最终结果
curl -XPOST 'localhost:9200/bank/_search?pretty' -d '
{
  "size": 0,
  "aggs": { "group_by_age": { "range": { "field": "age", "ranges": [ { "from": 20, "to": 30 }, { "from": 30, "to": 40 }, { "from": 40, "to": 50 } ] }, "aggs": { "group_by_gender": { "terms": { "field": "gender" }, "aggs": { "average_balance": { "avg": { "field": "balance" } } } } } } } }'

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