教程里的聚合例子在elasticsearch 6.0.1下的写法

[evanliang0]

原文链接：https://www.elastic.co/guide/cn/elasticsearch/guide/current/_analytics.html

原例子：
GET /megacorp/employee/_search
{
"aggs": {
"all_interests": {
"terms": { "field": "interests" }
}
}
}

在elasticsearch 6.0.1下执行会报如下错误：
{
"error": {
"root_cause": [
{
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [interests] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."
}
],
"type": "search_phase_execution_exception",
"reason": "all shards failed",
"phase": "query",
"grouped": true,
"failed_shards": [
{
"shard": 0,
"index": "megacorp",
"node": "S_-UcyJiRGmZvt1vDN-HjA",
"reason": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [interests] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead."
}
}
]
},
"status": 400
}

有两种方法可以解决，一种是设置fielddata=true，另一种是使用keyword，如下：
GET /megacorp/employee/_search
{
"aggs": {
"all_interests": {
"terms": {
"field": "interests.keyword"
}
}
}
}

官方文档：
https://www.elastic.co/guide/en/elasticsearch/reference/current/fielddata.html