前端执行sql：select count(distinct external_id) from HUMAN_INFO where facelib_id=2 ，底层走的es查询语句如下：
有没有办法提高es在聚合查询精度，如果在数量大的情况进行高精度聚合查询是不是就不能采用es了，只能采用mpp数据库了？
{
"query": {
"bool": {
"must": {
"term": {
"facelib_id": 2
}
}
}
},
"size": 0,
"aggs": {
"distinct": {
"cardinality": {
"field": "external_id"
}
}
}
}{
"took": 384,
"timed_out": false,
"_shards": {
"total": 1109,
"successful": 1109,
"failed": 0
},
"hits": {
"total": 39999915,
"max_score": 0,
"hits": []
},
"aggregations": {
"distinct": {
"value": 40044804
}
}
}有没有办法提高es在聚合查询精度，如果在数量大的情况进行高精度聚合查询是不是就不能采用es了，只能采用mpp数据库了？
3 个回复
jianjianhe
赞同来自: novia
The precision_threshold options allows to trade memory for accuracy, and defines a unique count below which counts are expected to be close to accurate. Above this value, counts might become a bit more fuzzy. The maximum supported value is 40000, thresholds above this number will have the same effect as a threshold of 40000. The default value is 3000.
即这个api是存在一定误差的，后续将查询语句添加precision_threshold参数，还是没能解决，估计是数据太大了，后续研究研究是否有好的解决办法：
Elastic_Cdw
赞同来自: jiangjiang2
laoyang360 - 《一本书讲透Elasticsearch》作者，Elastic认证工程师 [死磕Elasitcsearch]知识星球地址：http://t.cn/RmwM3N9；微信公众号：铭毅天下; 博客：https://elastic.blog.csdn.net
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