118 lines
2.9 KiB
Plaintext
118 lines
2.9 KiB
Plaintext
[[search-aggregations-metrics-stats-aggregation]]
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=== Stats aggregation
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++++
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<titleabbrev>Stats</titleabbrev>
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++++
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A `multi-value` metrics aggregation that computes stats over numeric values extracted from the aggregated documents.
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The stats that are returned consist of: `min`, `max`, `sum`, `count` and `avg`.
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Assuming the data consists of documents representing exams grades (between 0 and 100) of students
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[source,console]
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--------------------------------------------------
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POST /exams/_search?size=0
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{
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"aggs": {
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"grades_stats": { "stats": { "field": "grade" } }
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}
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}
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--------------------------------------------------
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// TEST[setup:exams]
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The above aggregation computes the grades statistics over all documents. The aggregation type is `stats` and the `field` setting defines the numeric field of the documents the stats will be computed on. The above will return the following:
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[source,console-result]
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--------------------------------------------------
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{
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...
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"aggregations": {
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"grades_stats": {
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"count": 2,
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"min": 50.0,
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"max": 100.0,
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"avg": 75.0,
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"sum": 150.0
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}
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}
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}
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--------------------------------------------------
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// TESTRESPONSE[s/\.\.\./"took": $body.took,"timed_out": false,"_shards": $body._shards,"hits": $body.hits,/]
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The name of the aggregation (`grades_stats` above) also serves as the key by which the aggregation result can be retrieved from the returned response.
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==== Script
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If you need to get the `stats` for something more complex than a single field,
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run the aggregation on a <<runtime,runtime field>>.
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[source,console]
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--------------------------------------------------
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POST /exams/_search
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{
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"size": 0,
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"runtime_mappings": {
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"grade.weighted": {
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"type": "double",
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"script": """
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emit(doc['grade'].value * doc['weight'].value)
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"""
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}
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},
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"aggs": {
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"grades_stats": {
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"stats": {
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"field": "grade.weighted"
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}
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}
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}
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}
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--------------------------------------------------
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// TEST[setup:exams]
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// TEST[s/_search/_search?filter_path=aggregations/]
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////
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[source,console-result]
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--------------------------------------------------
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{
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"aggregations": {
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"grades_stats": {
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"count": 2,
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"min": 150.0,
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"max": 200.0,
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"avg": 175.0,
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"sum": 350.0
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}
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}
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}
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--------------------------------------------------
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////
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==== Missing value
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The `missing` parameter defines how documents that are missing a value should be treated.
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By default they will be ignored but it is also possible to treat them as if they
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had a value.
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[source,console]
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--------------------------------------------------
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POST /exams/_search?size=0
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{
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"aggs": {
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"grades_stats": {
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"stats": {
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"field": "grade",
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"missing": 0 <1>
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}
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}
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}
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}
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--------------------------------------------------
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// TEST[setup:exams]
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<1> Documents without a value in the `grade` field will fall into the same bucket as documents that have the value `0`.
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