45 lines
1.7 KiB
Plaintext
45 lines
1.7 KiB
Plaintext
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[[query-dsl-dis-max-query]]
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=== Dis Max Query
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A query that generates the union of documents produced by its
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subqueries, and that scores each document with the maximum score for
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that document as produced by any subquery, plus a tie breaking increment
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for any additional matching subqueries.
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This is useful when searching for a word in multiple fields with
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different boost factors (so that the fields cannot be combined
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equivalently into a single search field). We want the primary score to
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be the one associated with the highest boost, not the sum of the field
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scores (as Boolean Query would give). If the query is "albino elephant"
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this ensures that "albino" matching one field and "elephant" matching
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another gets a higher score than "albino" matching both fields. To get
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this result, use both Boolean Query and DisjunctionMax Query: for each
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term a DisjunctionMaxQuery searches for it in each field, while the set
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of these DisjunctionMaxQuery's is combined into a BooleanQuery.
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The tie breaker capability allows results that include the same term in
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multiple fields to be judged better than results that include this term
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in only the best of those multiple fields, without confusing this with
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the better case of two different terms in the multiple fields.The
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default `tie_breaker` is `0.0`.
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This query maps to Lucene `DisjunctionMaxQuery`.
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[source,js]
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--------------------------------------------------
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{
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"dis_max" : {
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"tie_breaker" : 0.7,
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"boost" : 1.2,
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"queries" : [
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{
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"term" : { "age" : 34 }
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},
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{
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"term" : { "age" : 35 }
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}
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]
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}
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}
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--------------------------------------------------
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