161 lines
3.9 KiB
Markdown
161 lines
3.9 KiB
Markdown
---
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layout: default
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title: Boosting
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parent: Compound queries
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grand_parent: Query DSL
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nav_order: 30
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redirect_from:
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- /query-dsl/query-dsl/compound/boosting/
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---
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# Boosting queries
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If you're searching for the word "pitcher", your results may relate to either baseball players or containers for liquids. For a search in the context of baseball, you might want to completely exclude results that contain the words "glass" or "water" by using the `must_not` clause. However, if you want to keep those results but downgrade them in relevance, you can do so with `boosting` queries.
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A `boosting` query returns documents that match a `positive` query. Among those documents, the ones that also match the `negative` query are scored lower in relevance (their relevance score is multiplied by the negative boosting factor).
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## Example
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Consider an index with two documents that you index as follows:
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```json
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PUT testindex/_doc/1
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{
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"article_name": "The greatest pitcher in baseball history"
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}
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```
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```json
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PUT testindex/_doc/2
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{
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"article_name": "The making of a glass pitcher"
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}
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```
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Use the following match query to search for documents containing the word "pitcher":
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```json
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GET testindex/_search
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{
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"query": {
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"match": {
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"article_name": "pitcher"
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}
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}
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}
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```
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Both returned documents have the same relevance score:
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```json
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{
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"took": 5,
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"timed_out": false,
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"_shards": {
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"total": 1,
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"successful": 1,
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"skipped": 0,
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"failed": 0
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},
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"hits": {
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"total": {
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"value": 2,
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"relation": "eq"
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},
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"max_score": 0.18232156,
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"hits": [
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{
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"_index": "testindex",
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"_id": "1",
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"_score": 0.18232156,
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"_source": {
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"article_name": "The greatest pitcher in baseball history"
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}
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},
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{
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"_index": "testindex",
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"_id": "2",
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"_score": 0.18232156,
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"_source": {
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"article_name": "The making of a glass pitcher"
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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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Now use the following `boosting` query to search for documents containing the word "pitcher" but downgrade the documents that contain the words "glass", "crystal", or "water":
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```json
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GET testindex/_search
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{
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"query": {
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"boosting": {
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"positive": {
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"match": {
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"article_name": "pitcher"
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}
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},
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"negative": {
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"match": {
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"article_name": "glass crystal water"
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}
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},
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"negative_boost": 0.1
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}
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}
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}
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```
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{% include copy-curl.html %}
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Both documents are still returned, but the document with the word "glass" has a relevance score that is 10 times lower than in the previous case:
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```json
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{
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"took": 13,
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"timed_out": false,
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"_shards": {
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"total": 1,
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"successful": 1,
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"skipped": 0,
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"failed": 0
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},
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"hits": {
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"total": {
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"value": 2,
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"relation": "eq"
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},
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"max_score": 0.18232156,
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"hits": [
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{
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"_index": "testindex",
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"_id": "1",
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"_score": 0.18232156,
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"_source": {
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"article_name": "The greatest pitcher in baseball history"
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}
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},
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{
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"_index": "testindex",
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"_id": "2",
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"_score": 0.018232157,
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"_source": {
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"article_name": "The making of a glass pitcher"
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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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## Parameters
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The following table lists all top-level parameters supported by `boosting` queries.
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Parameter | Description
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:--- | :---
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`positive` | The query that a document must match to be returned in the results. Required.
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`negative` | If a document in the results matches this query, its relevance score is reduced by multiplying its original relevance score (produced by the `positive` query) by the `negative_boost` parameter. Required.
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`negative_boost` | A floating-point factor between 0 and 1.0 that the original relevance score is multiplied by in order to reduce the relevance of documents that match the `negative` query. Required.
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