ES脚本查询空字符串
本文介绍的查询方法是基于ES5.2版本的，可能对其他版本不适用。其他版本请参考官网： https://www.elastic.co/guide/en/elasticsearch/reference/5.2/modules-scripting-fields.html https://www.elastic.co/guide/en/elasticsearch/reference/5.2/modules-scripting-painless-syntax.html
查询字段为空的文档
curl localhost:9200/customer/_search?pretty -d'{
"size": 5,
"query": {
"bool": {
"must": {
"script": {
"script": {
"inline": "params._source.strnickname.length()<1",
"lang": "painless"
}
}
}
}
}
}'doc，fields和_source用法
doc：除了analyzed text 类型的字段，其余的字段默认都是开着doc_values的。doc可以查询text字段，前提是fielddata要开启。但是开启fielddata后，查询时将加载所有的term进入JVM heap。内存消耗太大，慎用。官网上说可用可用doc['field_name']查询，但是测试后发现不可以，但可通过doc.field_name查询。后又几经测试，发现是单引号的问题。doc['field_name']无法查询。总是报错：
"caused_by" : {
"type" : "script_exception",
"reason" : "compile error",
"caused_by" : {
"type" : "illegal_argument_exception",
"reason" : "Variable [field_name] is not defined."
},
"script_stack" : [
"doc[field_name].length() < ...",
" ^---- HERE"
],
"script" : "doc[field_name].length() < 1",
"lang" : "painless"
}但是doc[\u0027field_name\u0027]可以查询，doc['''field_name''']也可以查询。对上述例子可通过下述查询方式查询
curl localhost:9200/customer/_search?pretty -d'{
"size": 5,
"query": {
"bool": {
"must": {
"script": {
"script": {
"inline": "doc['\''strnickname'\''].length()<1",
"lang": "painless"
}
}
}
}
}
}'fields：仅标记为 "store": true 的字段可用，可通过_fields['field_name'].value or _fields['field_name'].values查询。
_source：是一个特殊的store fields。任何字段都可以使用。可通过_source.field_name访问。
curl -XPUT 'localhost:9200/my_index?pretty' -H 'Content-Type: application/json' -d'
{
"mappings": {
"my_type": {
"properties": {
"title": {
"type": "text"
},
"first_name": {
"type": "text",
"store": true
},
"last_name": {
"type": "text",
"store": true
}
}
}
}
}
'
curl -XPUT 'localhost:9200/my_index/my_type/1?pretty' -H 'Content-Type: application/json' -d'
{
"title": "Mr",
"first_name": "Barry",
"last_name": "White"
}
'
curl -XGET 'localhost:9200/my_index/_search?pretty' -H 'Content-Type: application/json' -d'
{
"script_fields": {
"source": {
"script": {
"inline": "params._source.title + ' '+ params._source.first_name + ' ' + params._source.last_name"
}
},
"stored_fields": {
"script": {
"inline": "params._fields['first_name'].value + ' ' + params._fields['last_name'].value"
}
}
}
}
'doc比store fields性能要好的多
Stored fields (which includes the stored _source field) are much slower than doc-values. They are optimised for returning several fields per result, while doc values are optimised for accessing the value of a specific field in many documents. It makes sense to use _source or stored fields when generating a script field for the top ten hits from a search result but, for other search and aggregation use cases, always prefer using doc values.