2013-08-28 19:24:34 -04:00
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[[query-dsl-multi-term-rewrite]]
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2015-05-05 02:27:52 -04:00
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== Multi Term Query Rewrite
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2013-08-28 19:24:34 -04:00
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Multi term queries, like
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<<query-dsl-wildcard-query,wildcard>> and
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<<query-dsl-prefix-query,prefix>> are called
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multi term queries and end up going through a process of rewrite. This
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also happens on the
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<<query-dsl-query-string-query,query_string>>.
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All of those queries allow to control how they will get rewritten using
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the `rewrite` parameter:
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* When not set, or set to `constant_score_auto`, defaults to
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automatically choosing either `constant_score_boolean` or
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`constant_score_filter` based on query characteristics.
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* `scoring_boolean`: A rewrite method that first translates each term
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into a should clause in a boolean query, and keeps the scores as
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computed by the query. Note that typically such scores are meaningless
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to the user, and require non-trivial CPU to compute, so it's almost
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always better to use `constant_score_auto`. This rewrite method will hit
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too many clauses failure if it exceeds the boolean query limit (defaults
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to `1024`).
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* `constant_score_boolean`: Similar to `scoring_boolean` except scores
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are not computed. Instead, each matching document receives a constant
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score equal to the query's boost. This rewrite method will hit too many
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clauses failure if it exceeds the boolean query limit (defaults to
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`1024`).
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* `constant_score_filter`: A rewrite method that first creates a private
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Filter by visiting each term in sequence and marking all docs for that
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term. Matching documents are assigned a constant score equal to the
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query's boost.
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* `top_terms_N`: A rewrite method that first translates each term into
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should clause in boolean query, and keeps the scores as computed by the
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query. This rewrite method only uses the top scoring terms so it will
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not overflow boolean max clause count. The `N` controls the size of the
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top scoring terms to use.
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* `top_terms_boost_N`: A rewrite method that first translates each term
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into should clause in boolean query, but the scores are only computed as
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the boost. This rewrite method only uses the top scoring terms so it
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will not overflow the boolean max clause count. The `N` controls the
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size of the top scoring terms to use.
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