Elasticsearch之深入聚合数据分析的实战
目录
两个核心概念：bucket和metric
家电卖场案例以及统计哪种颜色电视销量最高
统计每种颜色电视平均价格
bucket嵌套实现颜色+品牌的多层下钻分析
统计每种颜色电视最大最小价格
hitogram按价格区间统计电视销量和销售额
搜索+聚合：统计指定品牌下每个颜色的销量
cardinality去重算法以及每月销售品牌数量统计
percentiles百分比算法以及网站访问时延统计
string field聚合实验以及fielddata原理初探
两个核心概念：bucket和metric
bucket：分组，就是我们的bucket
metric：对一个数据分组执行的统计
家电卖场案例以及统计哪种颜色电视销量最高
以一个家电卖场中的电视销售数据为背景，来对各种品牌，各种颜色的电视的销量和销售额，进行各种各样角度的分析
POST /tvs/sales/_bulk
{ "index": {}}
{ "price" : 1000, "color" : "红色", "brand" : "长虹", "sold_date" : "2016-10-28" }
{ "index": {}}
{ "price" : 2000, "color" : "红色", "brand" : "长虹", "sold_date" : "2016-11-05" }
{ "index": {}}
{ "price" : 3000, "color" : "绿色", "brand" : "小米", "sold_date" : "2016-05-18" }
{ "index": {}}
{ "price" : 1500, "color" : "蓝色", "brand" : "TCL", "sold_date" : "2016-07-02" }
{ "index": {}}
{ "price" : 1200, "color" : "绿色", "brand" : "TCL", "sold_date" : "2016-08-19" }
{ "index": {}}
{ "price" : 2000, "color" : "红色", "brand" : "长虹", "sold_date" : "2016-11-05" }
{ "index": {}}
{ "price" : 8000, "color" : "红色", "brand" : "三星", "sold_date" : "2017-01-01" }
{ "index": {}}
{ "price" : 2500, "color" : "蓝色", "brand" : "小米", "sold_date" : "2017-02-12" }统计哪种颜色的电视销量最高
GET /tvs/sales/_search
{
"size" : 0,
"aggs" : {
"popular_colors" : {
"terms" : {
"field" : "color"
}
}
}
}size：只获取聚合结果，而不要执行聚合的原始数据
aggs：固定语法，要对一份数据执行分组聚合操作
popular_colors：就是对每个aggs，都要起一个名字，这个名字是随机的，你随便取什么都ok
terms：根据字段的值进行分组
field：根据指定的字段的值进行分组
结果
{
"took": 61,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"popular_color": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "红色",
"doc_count": 4
},
{
"key": "绿色",
"doc_count": 2
},
{
"key": "蓝色",
"doc_count": 2
}
]
}
}
}hits.hits：我们指定了size是0，所以hits.hits就是空的，否则会把执行聚合的那些原始数据给你返回回来
aggregations：聚合结果
popular_color：我们指定的某个聚合的名称
buckets：根据我们指定的field划分出的buckets
key：每个bucket对应的那个值
doc_count：这个bucket分组内，有多少个数据
数量，其实就是这种颜色的销量
每种颜色对应的bucket中的数据的
默认的排序规则：按照doc_count降序排序
统计每种颜色电视平均价格
GET /tvs/sales/_search
{
"size" : 0,
"aggs": {
"colors": {
"terms": {
"field": "color"
},
"aggs": {
"avg_price": {
"avg": {
"field": "price"
}
}
}
}
}
}
在一个aggs执行的bucket操作（terms），平级的json结构下，再加一个aggs，这个第二个aggs内部，同样取个名字，执行一个metric操作，avg，对之前的每个bucket中的数据的指定的field，price field，求一个平均值
"aggs": {
"avg_price": {
"avg": {
"field": "price"
}
}
}就是一个metric，就是一个对一个bucket分组操作之后，对每个bucket都要执行的一个metric
第一个metric，avg，求指定字段的平均值
{
"took": 28,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_color": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "红色",
"doc_count": 4,
"avg_price": {
"value": 3250
}
},
{
"key": "绿色",
"doc_count": 2,
"avg_price": {
"value": 2100
}
},
{
"key": "蓝色",
"doc_count": 2,
"avg_price": {
"value": 2000
}
}
]
}
}
}buckets，除了key和doc_count
avg_price：我们自己取的metric aggs的名字
value：我们的metric计算的结果，每个bucket中的数据的price字段求平均值后的结果
select avg(price)
from tvs.sales
group by color
bucket嵌套实现颜色+品牌的多层下钻分析
从颜色到品牌进行下钻分析，每种颜色的平均价格，以及找到每种颜色每个品牌的平均价格
我们可以进行多层次的下钻
比如说，现在红色的电视有4台，同时这4台电视中，有3台是属于长虹的，1台是属于小米的
红色电视中的3台长虹的平均价格是多少？
红色电视中的1台小米的平均价格是多少？
下钻的意思是，已经分了一个组了，比如说颜色的分组，然后还要继续对这个分组内的数据，再分组，比如一个颜色内，还可以分成多个不同的品牌的组，最后对每个最小粒度的分组执行聚合分析操作，这就叫做下钻分析
es，下钻分析，就要对bucket进行多层嵌套，多次分组
按照多个维度（颜色+品牌）多层下钻分析，而且学会了每个下钻维度（颜色，颜色+品牌），都可以对每个维度分别执行一次metric聚合操作
GET /tvs/sales/_search
{
"size": 0,
"aggs": {
"group_by_color": {
"terms": {
"field": "color"
},
"aggs": {
"color_avg_price": {
"avg": {
"field": "price"
}
},
"group_by_brand": {
"terms": {
"field": "brand"
},
"aggs": {
"brand_avg_price": {
"avg": {
"field": "price"
}
}
}
}
}
}
}
}结果
{
"took": 8,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_color": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "红色",
"doc_count": 4,
"color_avg_price": {
"value": 3250
},
"group_by_brand": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "长虹",
"doc_count": 3,
"brand_avg_price": {
"value": 1666.6666666666667
}
},
{
"key": "三星",
"doc_count": 1,
"brand_avg_price": {
"value": 8000
}
}
]
}
},
{
"key": "绿色",
"doc_count": 2,
"color_avg_price": {
"value": 2100
},
"group_by_brand": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "TCL",
"doc_count": 1,
"brand_avg_price": {
"value": 1200
}
},
{
"key": "小米",
"doc_count": 1,
"brand_avg_price": {
"value": 3000
}
}
]
}
},
{
"key": "蓝色",
"doc_count": 2,
"color_avg_price": {
"value": 2000
},
"group_by_brand": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "TCL",
"doc_count": 1,
"brand_avg_price": {
"value": 1500
}
},
{
"key": "小米",
"doc_count": 1,
"brand_avg_price": {
"value": 2500
}
}
]
}
}
]
}
}
}统计每种颜色电视最大最小价格
count：bucket，terms，自动就会有一个doc_count，就相当于是count
avg：avg aggs，求平均值
max：求一个bucket内，指定field值最大的那个数据
min：求一个bucket内，指定field值最小的那个数据
sum：求一个bucket内，指定field值的总和
一般来说，90%的常见的数据分析的操作，metric，无非就是count，avg，max，min，sum
GET /tvs/sales/_search
{
"size" : 0,
"aggs": {
"colors": {
"terms": {
"field": "color"
},
"aggs": {
"avg_price": { "avg": { "field": "price" } },
"min_price" : { "min": { "field": "price"} },
"max_price" : { "max": { "field": "price"} },
"sum_price" : { "sum": { "field": "price" } }
}
}
}
}求总和，就可以拿到一个颜色下的所有电视的销售总额
{
"took": 16,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_color": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "红色",
"doc_count": 4,
"max_price": {
"value": 8000
},
"min_price": {
"value": 1000
},
"avg_price": {
"value": 3250
},
"sum_price": {
"value": 13000
}
},
{
"key": "绿色",
"doc_count": 2,
"max_price": {
"value": 3000
},
"min_price": {
"value":
}, 1200
"avg_price": {
"value": 2100
},
"sum_price": {
"value": 4200
}
},
{
"key": "蓝色",
"doc_count": 2,
"max_price": {
"value": 2500
},
"min_price": {
"value": 1500
},
"avg_price": {
"value": 2000
},
"sum_price": {
"value": 4000
}
}
]
}
}
}hitogram按价格区间统计电视销量和销售额
histogram：类似于terms，也是进行bucket分组操作，接收一个field，按照这个field的值的各个范围区间，进行bucket分组操作
"histogram":{
"field": "price",
"interval": 2000
},interval：2000，划分范围，0~2000，2000~4000，4000~6000，6000~8000，8000~10000，buckets
去根据price的值，比如2500，看落在哪个区间内，比如2000~4000，此时就会将这条数据放入2000~4000对应的那个bucket中
bucket划分的方法，terms，将field值相同的数据划分到一个bucket中
bucket有了之后，一样的，去对每个bucket执行avg，count，sum，max，min，等各种metric操作，聚合分析
GET /tvs/sales/_search
{
"size" : 0,
"aggs":{
"price":{
"histogram":{
"field": "price",
"interval": 2000
},
"aggs":{
"revenue": {
"sum": {
"field" : "price"
}
}
}
}
}
}{
"took": 13,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_price": {
"buckets": [
{
"key": 0,
"doc_count": 3,
"sum_price": {
"value": 3700
}
},
{
"key": 2000,
"doc_count": 4,
"sum_price": {
"value": 9500
}
},
{
"key": 4000,
"doc_count": 0,
"sum_price": {
"value": 0
}
},
{
"key": 6000,
"doc_count: {
"value":": 0,
"sum_price" 0
}
},
{
"key": 8000,
"doc_count": 1,
"sum_price": {
"value": 8000
}
}
]
}
}
}搜索+聚合：统计指定品牌下每个颜色的销量
实际上来说，我们之前学习的搜索相关的知识，完全可以和聚合组合起来使用
select count(*)
from tvs.sales
where brand like "%长%"
group by price
es aggregation，scope，任何的聚合，都必须在搜索出来的结果数据中之行，搜索结果，就是聚合分析操作的scope
GET /tvs/sales/_search
{
"size": 0,
"query": {
"term": {
"brand": {
"value": "小米"
}
}
},
"aggs": {
"group_by_color": {
"terms": {
"field": "color"
}
}
}
}{
"took": 5,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_color": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "绿色",
"doc_count": 1
},
{
"key": "蓝色",
"doc_count": 1
}
]
}
}
}cardinality去重算法以及每月销售品牌数量统计
cartinality metric，对每个bucket中的指定的field进行去重，取去重后的count，类似于count(distcint)
GET /tvs/sales/_search
{
"size" : 0,
"aggs" : {
"months" : {
"date_histogram": {
"field": "sold_date",
"interval": "month"
},
"aggs": {
"distinct_colors" : {
"cardinality" : {
"field" : "brand"
}
}
}
}
}
}{
"took": 70,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 8,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_sold_date": {
"buckets": [
{
"key_as_string": "2016-05-01T00:00:00.000Z",
"key": 1462060800000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2016-06-01T00:00:00.000Z",
"key": 1464739200000,
"doc_count": 0,
"distinct_brand_cnt": {
"value": 0
}
},
{
"key_as_string": "2016-07-01T00:00:00.000Z",
"key": 1467331200000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2016-08-01T00:00:00.000Z",
"key": 1470009600000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2016-09-01T00:00:00.000Z",
"key": 1472688000000,
"doc_count": 0,
"distinct_brand_cnt": {
"value": 0
}
},
{
"key_as_string": "2016-10-01T00:00:00.000Z",
"key": 1475280000000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2016-11-01T00:00:00.000Z",
"key": 1477958400000,
"doc_count": 2,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2016-12-01T00:00:00.000Z",
"key": 1480550400000,
"doc_count": 0,
"distinct_brand_cnt": {
"value": 0
}
},
{
"key_as_string": "2017-01-01T00:00:00.000Z",
"key": 1483228800000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
},
{
"key_as_string": "2017-02-01T00:00:00.000Z",
"key": 1485907200000,
"doc_count": 1,
"distinct_brand_cnt": {
"value": 1
}
}
]
}
}
}percentiles百分比算法以及网站访问时延统计
需求：比如有一个网站，记录下了每次请求的访问的耗时，需要统计tp50，tp90，tp99
tp50：50%的请求的耗时最长在多长时间
tp95：95%的请求的耗时最长在多长时间
tp99：99%的请求的耗时最长在多长时间
PUT /website
{
"mappings": {
"logs": {
"properties": {
"latency": {
"type": "long"
},
"province": {
"type": "keyword"
},
"timestamp": {
"type": "date"
}
}
}
}
}POST /website/logs/_bulk
{ "index": {}}
{ "latency" : 105, "province" : "江苏", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 83, "province" : "江苏", "timestamp" : "2016-10-29" }
{ "index": {}}
{ "latency" : 92, "province" : "江苏", "timestamp" : "2016-10-29" }
{ "index": {}}
{ "latency" : 112, "province" : "江苏", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 68, "province" : "江苏", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 76, "province" : "江苏", "timestamp" : "2016-10-29" }
{ "index": {}}
{ "latency" : 101, "province" : "新疆", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 275, "province" : "新疆", "timestamp" : "2016-10-29" }
{ "index": {}}
{ "latency" : 166, "province" : "新疆", "timestamp" : "2016-10-29" }
{ "index": {}}
{ "latency" : 654, "province" : "新疆", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 389, "province" : "新疆", "timestamp" : "2016-10-28" }
{ "index": {}}
{ "latency" : 302, "province" : "新疆", "timestamp" : "2016-10-29" }pencentiles
GET /website/logs/_search
{
"size": 0,
"aggs": {
"latency_percentiles": {
"percentiles": {
"field": "latency",
"percents": [
50,
95,
99
]
}
},
"latency_avg": {
"avg": {
"field": "latency"
}
}
}
}{
"took": 31,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 12,
"max_score": 0,
"hits": []
},
"aggregations": {
"latency_avg": {
"value": 201.91666666666666
},
"latency_percentiles": {
"values": {
"50.0": 108.5,
"95.0": 508.24999999999983,
"99.0": 624.8500000000001
}
}
}
}返回字段的含义：50%的请求，在108.5ms内，不是完全准确的使用一定的算法算出来的
GET /website/logs/_search
{
"size": 0,
"aggs": {
"group_by_province": {
"terms": {
"field": "province"
},
"aggs": {
"latency_percentiles": {
"percentiles": {
"field": "latency",
"percents": [
50,
95,
99
]
}
},
"latency_avg": {
"avg": {
"field": "latency"
}
}
}
}
}
}{
"took": 33,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 12,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_province": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "新疆",
"doc_count": 6,
"latency_avg": {
"value": 314.5
},
"latency_percentiles": {
"values": {
"50.0": 288.5,
"95.0": 587.75,
"99.0": 640.75
}
}
},
{
"key": "江苏",
"doc_count": 6,
"latency_avg": {
"value": 89.33333333333333
},
"latency_percentiles": {
"values": {
"50.0": 87.5,
"95.0": 110.25,
"99.0": 111.65
}
}
}
]
}
}
}
string field聚合实验以及fielddata原理初探
1、对于分词的field执行aggregation，发现报错。。。
GET /test_index/test_type/_search
{
"aggs": {
"group_by_test_field": {
"terms": {
"field": "test_field"
}
}
}
}{
"error": {
"root_cause": [
{
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [test_field] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
],
"type": "search_phase_execution_exception",
"reason": "all shards failed",
"phase": "query",
"grouped": true,
"failed_shards": [
{
"shard": 0,
"index": "test_index",
"node": "4onsTYVZTjGvIj9_spWz2w",
"reason": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [test_field] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
}
],
"caused_by": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [test_field] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
},
"status": 400
}对分词的field，直接执行聚合操作，会报错，大概意思是说，你必须要打开fielddata，然后将正排索引数据加载到内存中，才可以对分词的field执行聚合操作，而且会消耗很大的内存
2、给分词的field，设置fielddata=true，发现可以执行，但是结果却。。。
POST /test_index/_mapping/test_type
{
"properties": {
"test_field": {
"type": "text",
"fielddata": true
}
}
}
{
"test_index": {
"mappings": {
"test_type": {
"properties": {
"test_field": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
},
"fielddata": true
}
}
}
}
}
}GET /test_index/test_type/_search
{
"size": 0,
"aggs": {
"group_by_test_field": {
"terms": {
"field": "test_field"
}
}
}
}{
"took": 23,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_test_field": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "test",
"doc_count": 2
}
]
}
}
}如果要对分词的field执行聚合操作，必须将fielddata设置为true
3、使用内置field不分词，对string field进行聚合
GET /test_index/test_type/_search
{
"size": 0,
"aggs": {
"group_by_test_field": {
"terms": {
"field": "test_field.keyword"
}
}
}
}{
"took": 3,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0,
"hits": []
},
"aggregations": {
"group_by_test_field": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "test",
"doc_count": 2
}
]
}
}
}如果对不分词的field执行聚合操作，直接就可以执行，不需要设置fieldata=true
4、分词field+fielddata的工作原理
doc value --> 不分词的所有field，可以执行聚合操作 --> 如果你的某个field不分词，那么在index-time，就会自动生成doc value --> 针对这些不分词的field执行聚合操作的时候，自动就会用doc value来执行
分词field，是没有doc value的。。。在index-time，如果某个field是分词的，那么是不会给它建立doc value正排索引的，因为分词后，占用的空间过于大，所以默认是不支持分词field进行聚合的
分词field默认没有doc value，所以直接对分词field执行聚合操作，是会报错的
对于分词field，必须打开和使用fielddata，完全存在于纯内存中。。。结构和doc value类似。。。如果是ngram或者是大量term，那么必将占用大量的内存。。。
如果一定要对分词的field执行聚合，那么必须将fielddata=true，然后es就会在执行聚合操作的时候，现场将field对应的数据，建立一份fielddata正排索引，fielddata正排索引的结构跟doc value是类似的，但是只会将fielddata正排索引加载到内存中来，然后基于内存中的fielddata正排索引执行分词field的聚合操作
如果直接对分词field执行聚合，报错，才会让我们开启fielddata=true，告诉我们，会将fielddata uninverted index，正排索引，加载到内存，会耗费内存空间
为什么fielddata必须在内存？因为大家自己思考一下，分词的字符串，需要按照term进行聚合，需要执行更加复杂的算法和操作，如果基于磁盘和os cache，那么性能会很差