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Disjunction max queries
A disjunction max (dis_max) query returns any document that matches one or more query clauses. For documents that match multiple query clauses, the relevance score is set to the highest relevance score from all matching query clauses.
When the relevance scores of the returned documents are identical, you can use the tie_breaker parameter to give more weight to documents that match multiple query clauses.
Example
Consider an index with two documents that you index as follows:
PUT testindex1/_doc/1
{
"title": " The Top 10 Shakespeare Poems",
"description": "Top 10 sonnets of England's national poet and the Bard of Avon"
}
PUT testindex1/_doc/2
{
"title": "Sonnets of the 16th Century",
"body": "The poems written by various 16-th century poets"
}
Use a dis_max query to search for documents that contain the words “Shakespeare works”:
GET testindex1/_search
{
"query": {
"dis_max": {
"queries": [
{ "match": { "title": "Shakespeare poems" }},
{ "match": { "body": "Shakespeare poems" }}
]
}
}
}
The response contains both documents:
{
"took": 8,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 1.3862942,
"hits": [
{
"_index": "testindex1",
"_id": "1",
"_score": 1.3862942,
"_source": {
"title": " The Top 10 Shakespeare Poems",
"description": "Top 10 sonnets of England's national poet and the Bard of Avon"
}
},
{
"_index": "testindex1",
"_id": "2",
"_score": 0.2876821,
"_source": {
"title": "Sonnets of the 16th Century",
"body": "The poems written by various 16-th century poets"
}
}
]
}
}
Parameters
The following table lists all top-level parameters supported by dis_max queries.
| Parameter | Description |
|---|---|
queries | An array of one or more query clauses that are used to match documents. A document must match at least one query clause to be returned in the results. If a document matches multiple query clauses, the relevance score is set to the highest relevance score from all matching query clauses. Required. |
tie_breaker | A floating-point factor between 0 and 1.0 that is used to give more weight to documents that match multiple query clauses. In this case, the relevance score of a document is calculated using the following algorithm: Take the highest relevance score from all matching query clauses, multiply the scores from all other matching clauses by the tie_breaker value, and add the relevance scores together, normalizing them. Optional. Default is 0 (which means only the highest score counts). |