一、问题源起
在elasticsearch的查询中，我们一般直接通过URL来设置要search的index； 如果我们需要查询的索引比较多并且没有什么规律的话，就会面临一个尴尬的局面，超过URL的长度限制；
二、测试环境
elasticsearch 6.8.12
测试数据
新增三个测试的index，每个index里边一个document；
PUT test1/_doc/1
{
"id":1,
"name":"test1-1"
}
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_version" : 1,
# "result" : "created",
# "_shards" : {
# "total" : 2,
# "successful" : 1,
# "failed" : 0
# },
# "_seq_no" : 0,
# "_primary_term" : 1
# }
PUT test2/_doc/1
{
"id":1,
"name":"test2-1"
}
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_version" : 1,
# "result" : "created",
# "_shards" : {
# "total" : 2,
# "successful" : 1,
# "failed" : 0
# },
# "_seq_no" : 0,
# "_primary_term" : 1
# }
PUT test3/_doc/1
{
"id":1,
"name":"test3-1"
}
# {
# "_index" : "test3",
# "_type" : "_doc",
# "_id" : "1",
# "_version" : 1,
# "result" : "created",
# "_shards" : {
# "total" : 2,
# "successful" : 1,
# "failed" : 0
# },
# "_seq_no" : 0,
# "_primary_term" : 1
# }
三、URL中指定multi index
直接在URL中指定搜索特定的index
POST test1/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 5,
# "successful" : 5,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 1,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# }
# ]
# }
# }
可以通过都好分割同时搜索多个index；
POST test1,test2/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 1,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# }
# ]
# }
# }
我们可以使用关键字_all指定搜索所有的index；
POST _all/_search
{
"query": {
"match_all": {}
}
}
{
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 15,
# "successful" : 15,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 3,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# },
# {
# "_index" : "test3",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test3-1"
# }
# }
# ]
# }
# }
也可以使用通配符*来匹配一些名字有共同特征的index；
POST test*/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 1,
# "timed_out" : false,
# "_shards" : {
# "total" : 15,
# "successful" : 15,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 3,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# },
# {
# "_index" : "test3",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test3-1"
# }
# }
# ]
# }
# }
还可以使用-来排除某个index；
POST test*,-test2/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test3",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test3-1"
# }
# }
# ]
# }
# }
四、URL中multi index的一些控制选项
如果我们显示search一个不存在的或者关闭的index就会报错；
POST test4/_search
{
"query": {
"match_all": {}
}
}
# {
# "error" : {
# "root_cause" : [
# {
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "test4",
# "index_uuid" : "_na_",
# "index" : "test4"
# }
# ],
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "test4",
# "index_uuid" : "_na_",
# "index" : "test4"
# },
# "status" : 404
# }
POST test3/_close
#
# {
# "acknowledged" : true
# }
POST test3/_search
{
"query": {
"match_all": {}
}
}
# {
# "error": {
# "root_cause": [
# {
# "type": "index_closed_exception",
# "reason": "closed",
# "index_uuid": "KI7Iv4eGRIOk6MsycXokNQ",
# "index": "test3"
# }
# ],
# "type": "index_closed_exception",
# "reason": "closed",
# "index_uuid": "KI7Iv4eGRIOk6MsycXokNQ",
# "index": "test3"
# },
# "status": 400
# }
我们可以使用ignore_unavailable来忽略不存在或者关闭的index；
POST test4/_search?ignore_unavailable=true
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 0,
# "successful" : 0,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 0,
# "max_score" : 0.0,
# "hits" : [ ]
# }
# }
POST test3/_search?ignore_unavailable=true
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 0,
# "successful" : 0,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 0,
# "max_score" : 0.0,
# "hits" : [ ]
# }
# }
如果通过通配符、_all隐式的指定search的index，如果不存在则默认不会报错，不过可以通过allow_no_indices=false来让elasticsearch报错；
POST noexist*/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 0,
# "successful" : 0,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 0,
# "max_score" : 0.0,
# "hits" : [ ]
# }
# }
POST noexist*/_search?allow_no_indices=false
{
"query": {
"match_all": {}
}
}
# {
# "error" : {
# "root_cause" : [
# {
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "noexist*",
# "index_uuid" : "_na_",
# "index" : "noexist*"
# }
# ],
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "noexist*",
# "index_uuid" : "_na_",
# "index" : "noexist*"
# },
# "status" : 404
# }
POST test3*/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 0,
# "successful" : 0,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 0,
# "max_score" : 0.0,
# "hits" : [ ]
# }
# }
POST test3*/_search?allow_no_indices=false
{
"query": {
"match_all": {}
}
}
# {
# "error" : {
# "root_cause" : [
# {
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "test3*"
# }
# ],
# "type" : "index_not_found_exception",
# "reason" : "no such index",
# "resource.type" : "index_or_alias",
# "resource.id" : "test3*"
# },
# "status" : 404
# }
我们也可以使用expand_wildcards来控制展开哪些index，可选值open、closed、none、all；
默认只扩展open；
POST test*/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# }
# ]
# }
# }
POST test*/_search?expand_wildcards=all
{
"query": {
"match_all": {}
}
}
# {
# "error": {
# "root_cause": [
# {
# "type": "index_closed_exception",
# "reason": "closed",
# "index_uuid": "KI7Iv4eGRIOk6MsycXokNQ",
# "index": "test3"
# }
# ],
# "type": "index_closed_exception",
# "reason": "closed",
# "index_uuid": "KI7Iv4eGRIOk6MsycXokNQ",
# "index": "test3"
# },
# "status": 400
# }
POST test*/_search?expand_wildcards=all&ignore_unavailable=true
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# }
# ]
# }
# }
五、使用index aliases封装物理index
aliases是物理索引的别名，请求api的时候，elasticsearch会自动将aliases转化为对应的物理index name；
别名既可以映射到某个特定的index，也可以映射到多个index；
别名也可以同时应用过滤条件，实现只对index的局部数据进行搜索；
POST /_aliases
{
"actions" : [
{ "add" : { "index" : "test*", "alias" : "all_test_indices" } }
]
}
# {
# "acknowledged" : true
# }
POST all_test_indices/_search
{
"query": {
"match_all": {}
}
}
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# }
# ]
# }
# }
六、multi search--通过body指定index
Multi Search API的主要目的是实现在一个API里边实现多个search请求，其通过如下格式分别通过header指定index，body指定查询语句；
header\n
body\n
header\n
body\n
Multi Search API除了与前两者具有相同的指定index name的能力，最大的优势就是通过body传递index name，轻松突破URL的长度限制的局限性；
还有一点就是Multi Search API支持大量的没有特定规律的index name，例如跟时间序列有关的index name等；
GET _msearch
{"index":"test*"}
{"query" : {"match_all" : {}}}
# {
# "responses" : [
# {
# "took" : 0,
# "timed_out" : false,
# "_shards" : {
# "total" : 10,
# "successful" : 10,
# "skipped" : 0,
# "failed" : 0
# },
# "hits" : {
# "total" : 2,
# "max_score" : 1.0,
# "hits" : [
# {
# "_index" : "test1",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test1-1"
# }
# },
# {
# "_index" : "test2",
# "_type" : "_doc",
# "_id" : "1",
# "_score" : 1.0,
# "_source" : {
# "id" : 1,
# "name" : "test2-1"
# }
# }
# ]
# },
# "status" : 200
# }
# ]
# }