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8250aa4267
This change removes the `postings` highlighter. This highlighter has been removed from Lucene master (7.x) because it behaves exactly like the `unified` highlighter when index_options is set to `offsets`: https://issues.apache.org/jira/browse/LUCENE-7815 It also makes the `unified` highlighter the default choice for highlighting a field (if `type` is not provided). The strategy used internally by this highlighter remain the same as before, it checks `term_vectors` first, then `postings` and ultimately it re-analyzes the text. Ultimately it rewrites the docs so that the options that the `unified` highlighter cannot handle are clearly marked as such. There are few features that the `unified` highlighter is not able to handle which is why the other highlighters (`plain` and `fvh`) are still available. I'll open separate issues for these features and we'll deprecate the `fvh` and `plain` highlighters when full support for these features have been added to the `unified`.
71 lines
1.6 KiB
Plaintext
71 lines
1.6 KiB
Plaintext
[[index-options]]
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=== `index_options`
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The `index_options` parameter controls what information is added to the
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inverted index, for search and highlighting purposes. It accepts the
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following settings:
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[horizontal]
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`docs`::
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Only the doc number is indexed. Can answer the question _Does this term
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exist in this field?_
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`freqs`::
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Doc number and term frequencies are indexed. Term frequencies are used to
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score repeated terms higher than single terms.
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`positions`::
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Doc number, term frequencies, and term positions (or order) are indexed.
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Positions can be used for
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<<query-dsl-match-query-phrase,proximity or phrase queries>>.
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`offsets`::
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Doc number, term frequencies, positions, and start and end character
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offsets (which map the term back to the original string) are indexed.
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Offsets are used by the <<unified-highlighter,unified highlighter>> to speed up highlighting.
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<<mapping-index,Analyzed>> string fields use `positions` as the default, and
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all other fields use `docs` as the default.
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[source,js]
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--------------------------------------------------
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PUT my_index
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{
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"mappings": {
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"my_type": {
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"properties": {
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"text": {
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"type": "text",
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"index_options": "offsets"
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}
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}
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}
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}
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}
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PUT my_index/my_type/1
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{
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"text": "Quick brown fox"
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}
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GET my_index/_search
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{
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"query": {
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"match": {
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"text": "brown fox"
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}
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},
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"highlight": {
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"fields": {
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"text": {} <1>
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}
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}
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}
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--------------------------------------------------
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// CONSOLE
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<1> The `text` field will use the postings for the highlighting by default because `offsets` are indexed.
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