我正在尝试使用NEST实现ElasticSearch查询,以便能够生成键/值对的结果,其中键是日期,值是计数。我查询的文件都有一个created_date,我想计算每天插入的文件数量,过去7天或类似情况。
我已经检查了IElasticClient的Count方法,但这似乎给了我一个总数而不是每天。我想我需要对数据做一个方面,但不能完全弄清楚如何实现它。
任何帮助将不胜感激:)
答案 0 :(得分:1)
你想要的是date_histogram
- facet。
这是一个应该涵盖我可以解释你想要的各种方式的例子:
export ELASTICSEARCH_ENDPOINT="http://localhost:9200"
# Index documents
curl -XPOST "$ELASTICSEARCH_ENDPOINT/_bulk?refresh=true" -d '
{"index":{"_index":"play","_type":"type","_id":1}}
{"created_date":"2013-09-30T12:00:00Z","key":"foo","count":12}
{"index":{"_index":"play","_type":"type","_id":2}}
{"created_date":"2013-09-30T13:00:00Z","key":"bar","count":14}
{"index":{"_index":"play","_type":"type","_id":3}}
{"created_date":"2013-10-01T12:00:00Z","key":"foo","count":42}
{"index":{"_index":"play","_type":"type","_id":4}}
{"created_date":"2013-10-01T14:00:00Z","key":"foo","count":13}
'
# Do searches
curl -XPOST "$ELASTICSEARCH_ENDPOINT/_search?pretty" -d '
{
"facets": {
"foos_per_interval": {
"date_histogram": {
"key_field": "created_date",
"value_field": "count",
"interval": "day"
},
"facet_filter": {
"term": {
"key": "foo"
}
}
}
}
}
'
{
"took" : 1,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"failed" : 0
},
"hits" : {
"total" : 4,
"max_score" : 1.0,
"hits" : [ {
"_index" : "play",
"_type" : "type",
"_id" : "1",
"_score" : 1.0, "_source" : {"created_date":"2013-09-30T12:00:00Z","key":"foo","count":12}
}, {
"_index" : "play",
"_type" : "type",
"_id" : "2",
"_score" : 1.0, "_source" : {"created_date":"2013-09-30T13:00:00Z","key":"bar","count":14}
}, {
"_index" : "play",
"_type" : "type",
"_id" : "3",
"_score" : 1.0, "_source" : {"created_date":"2013-10-01T12:00:00Z","key":"foo","count":42}
}, {
"_index" : "play",
"_type" : "type",
"_id" : "4",
"_score" : 1.0, "_source" : {"created_date":"2013-10-01T14:00:00Z","key":"foo","count":13}
} ]
},
"facets" : {
"foos_per_interval" : {
"_type" : "date_histogram",
"entries" : [ {
"time" : 1380499200000,
"count" : 1,
"min" : 12.0,
"max" : 12.0,
"total" : 12.0,
"total_count" : 1,
"mean" : 12.0
}, {
"time" : 1380585600000,
"count" : 2,
"min" : 13.0,
"max" : 42.0,
"total" : 55.0,
"total_count" : 2,
"mean" : 27.5
} ]
}
}
}
答案 1 :(得分:1)
走向分面确实是要走的路:
http://www.elasticsearch.org/guide/reference/api/search/facets/date-histogram-facet/
public class Doc
{
public string Id { get; set; }
public DateTime CreatedOn { get; set; }
}
public void TempFacetExample()
{
var result = this._client.Search<Doc>(s => s
.FacetDateHistogram(fd => fd
.OnField(p => p.CreatedOn)
.Interval(DateInterval.Day)
//global forces it to count out of scope
//from the main query (if any)
.Global()
.FacetFilter(ff => ff
.Range(rf => rf
.From(DateTime.UtcNow.AddDays(-7))
.To(DateTime.UtcNow)
)
)
)
);
var facetBucket = result.Facet<DateHistogramFacet>(p => p.CreatedOn);
//facetBucket.Items now holds the days with counts
//if I remember correctly elasticsearch wont return empty buckets
//so you have to handle missing days (that have no docs).
}