76 lines
1.9 KiB
Plaintext
76 lines
1.9 KiB
Plaintext
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[[caching-heavy-aggregations]]
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== Caching heavy aggregations
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Frequently used aggregations (e.g. for display on the home page of a website)
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can be cached for faster responses. These cached results are the same results
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that would be returned by an uncached aggregation -- you will never get stale
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results.
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See <<index-modules-shard-query-cache>> for more details.
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[[returning-only-agg-results]]
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== Returning only aggregation results
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There are many occasions when aggregations are required but search hits are not. For these cases the hits can be ignored by
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setting `size=0`. For example:
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[source,js]
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--------------------------------------------------
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$ curl -XGET 'http://localhost:9200/twitter/tweet/_search' -d '{
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"size": 0,
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"aggregations": {
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"my_agg": {
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"terms": {
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"field": "text"
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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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Setting `size` to `0` avoids executing the fetch phase of the search making the request more efficient.
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[[agg-metadata]]
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== Aggregation Metadata
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You can associate a piece of metadata with individual aggregations at request time that will be returned in place
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at response time.
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Consider this example where we want to associate the color blue with our `terms` aggregation.
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[source,js]
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--------------------------------------------------
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{
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...
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aggs": {
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"titles": {
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"terms": {
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"field": "title"
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},
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"meta": {
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"color": "blue"
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},
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}
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}
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}
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--------------------------------------------------
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Then that piece of metadata will be returned in place for our `titles` terms aggregation
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[source,js]
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--------------------------------------------------
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{
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...
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"aggregations": {
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"titles": {
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"meta": {
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"color" : "blue"
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},
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"buckets": [
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]
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}
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}
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}
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--------------------------------------------------
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