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Wuwan, Qi
050b395397
Reviewed-by: Kacur, Michal <michal.kacur@t-systems.com> Co-authored-by: Wuwan, Qi <wuwanqi1@noreply.gitea.eco.tsi-dev.otc-service.com> Co-committed-by: Wuwan, Qi <wuwanqi1@noreply.gitea.eco.tsi-dev.otc-service.com>
63 lines
2.1 KiB
HTML
63 lines
2.1 KiB
HTML
<a name="css_01_0174"></a><a name="css_01_0174"></a>
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<h1 class="topictitle1">Grouping and Aggregation of Low-cardinality Fields</h1>
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<div id="body0000001081675855"><p id="css_01_0174__en-us_topic_0000001223594380_p8060118">Low-cardinality fields have high data clustering performance when being sorted, which facilitates vectorized optimization. Assume that the following query statement exists:</p>
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<pre class="screen" id="css_01_0174__screen3319724112017">POST testindex/_search
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{
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"size": 0,
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"aggs": {
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"groupby_region": {
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"terms": {
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"field": "region"
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},
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"aggs": {
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"groupby_host": {
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"terms": {
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"field": "host"
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},
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"aggs": {
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"avg_cpu_usage": {
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"avg": {
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"field": "cpu_usage"
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}
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}
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}
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}
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}
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}
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}
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}</pre>
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<p id="css_01_0174__p837072313217">Assume that the <strong id="css_01_0174__b1021715351589">region</strong> and <strong id="css_01_0174__b72176354812">host</strong> are low-cardinality fields. To use the enhanced aggregation, set the parameters as follows:</p>
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<div class="note" id="css_01_0174__note326443032220"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="css_01_0174__p4264830122217">The clustering key must be a prefix subset of the sorting key.</p>
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</div></div>
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<pre class="screen" id="css_01_0174__screen4220515220">// Configure an index
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"settings" : {
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"index" : {
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"search" : {
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"turbo" : {
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"enabled" : "true" // Enable optimization
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}
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},
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"sort" : { // Specify a sorting key
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"field" : [
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"region",
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"host",
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"other"
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]
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},
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"cluster" : {
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"field" : [ // Specify a clustering key
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"region",
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"host"
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]
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}
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}
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}</pre>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="css_01_0172.html">Enhanced Aggregation</a></div>
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</div>
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</div>
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