276 lines
6.6 KiB
Plaintext
276 lines
6.6 KiB
Plaintext
[[search-suggesters]]
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== Suggesters
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The suggest feature suggests similar looking terms based on a provided
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text by using a suggester. The suggest feature is available from version
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`0.90.0.Beta1`. Parts of the suggest feature are still under
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development.
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The suggest request part is either defined alongside the query part in a
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`_search` request or via the REST `_suggest` endpoint.
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[source,js]
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--------------------------------------------------
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curl -s -XPOST 'localhost:9200/_search' -d '{
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"query" : {
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...
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},
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"suggest" : {
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...
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}
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}'
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--------------------------------------------------
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Suggest requests executed against the `_suggest` endpoint should omit
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the surrounding `suggest` element which is only used if the suggest
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request is part of a search.
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[source,js]
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--------------------------------------------------
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curl -XPOST 'localhost:9200/_suggest' -d '{
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"my-suggestion" : {
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"text" : "the amsterdma meetpu",
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"term" : {
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"field" : "body"
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}
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}
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}'
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--------------------------------------------------
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Several suggestions can be specified per request. Each suggestion is
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identified with an arbitrary name. In the example below two suggestions
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are requested. Both `my-suggest-1` and `my-suggest-2` suggestions use
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the `term` suggester, but have a different `text`.
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[source,js]
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--------------------------------------------------
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"suggest" : {
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"my-suggest-1" : {
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"text" : "the amsterdma meetpu",
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"term" : {
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"field" : "body"
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}
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},
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"my-suggest-2" : {
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"text" : "the rottredam meetpu",
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"term" : {
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"field" : "title",
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}
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}
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}
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--------------------------------------------------
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The below suggest response example includes the suggestion response for
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`my-suggest-1` and `my-suggest-2`. Each suggestion part contains
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entries. Each entry is effectively a token from the suggest text and
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contains the suggestion entry text, the original start offset and length
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in the suggest text and if found an arbitrary number of options.
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[source,js]
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--------------------------------------------------
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{
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...
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"suggest": {
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"my-suggest-1": [
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{
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"text" : "amsterdma",
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"offset": 4,
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"length": 9,
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"options": [
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...
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]
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},
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...
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],
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"my-suggest-2" : [
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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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Each options array contains an option object that includes the
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suggested text, its document frequency and score compared to the suggest
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entry text. The meaning of the score depends on the used suggester. The
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term suggester's score is based on the edit distance.
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[source,js]
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--------------------------------------------------
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"options": [
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{
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"text": "amsterdam",
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"freq": 77,
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"score": 0.8888889
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},
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...
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]
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--------------------------------------------------
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[float]
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=== Global suggest text
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To avoid repetition of the suggest text, it is possible to define a
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global text. In the example below the suggest text is defined globally
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and applies to the `my-suggest-1` and `my-suggest-2` suggestions.
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[source,js]
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--------------------------------------------------
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"suggest" : {
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"text" : "the amsterdma meetpu"
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"my-suggest-1" : {
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"term" : {
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"field" : "title"
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}
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},
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"my-suggest-2" : {
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"term" : {
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"field" : "body"
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}
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}
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}
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--------------------------------------------------
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The suggest text can in the above example also be specified as
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suggestion specific option. The suggest text specified on suggestion
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level override the suggest text on the global level.
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[float]
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=== Other suggest example.
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In the below example we request suggestions for the following suggest
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text: `devloping distibutd saerch engies` on the `title` field with a
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maximum of 3 suggestions per term inside the suggest text. Note that in
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this example we use the `count` search type. This isn't required, but a
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nice optimization. The suggestions are gather in the `query` phase and
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in the case that we only care about suggestions (so no hits) we don't
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need to execute the `fetch` phase.
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[source,js]
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--------------------------------------------------
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curl -s -XPOST 'localhost:9200/_search?search_type=count' -d '{
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"suggest" : {
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"my-title-suggestions-1" : {
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"text" : "devloping distibutd saerch engies",
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"term" : {
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"size" : 3,
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"field" : "title"
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}
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}
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}
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}'
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--------------------------------------------------
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The above request could yield the response as stated in the code example
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below. As you can see if we take the first suggested options of each
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suggestion entry we get `developing distributed search engines` as
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result.
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[source,js]
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--------------------------------------------------
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{
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...
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"suggest": {
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"my-title-suggestions-1": [
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{
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"text": "devloping",
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"offset": 0,
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"length": 9,
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"options": [
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{
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"text": "developing",
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"freq": 77,
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"score": 0.8888889
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},
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{
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"text": "deloping",
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"freq": 1,
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"score": 0.875
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},
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{
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"text": "deploying",
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"freq": 2,
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"score": 0.7777778
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}
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]
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},
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{
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"text": "distibutd",
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"offset": 10,
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"length": 9,
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"options": [
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{
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"text": "distributed",
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"freq": 217,
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"score": 0.7777778
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},
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{
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"text": "disributed",
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"freq": 1,
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"score": 0.7777778
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},
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{
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"text": "distribute",
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"freq": 1,
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"score": 0.7777778
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}
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]
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},
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{
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"text": "saerch",
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"offset": 20,
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"length": 6,
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"options": [
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{
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"text": "search",
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"freq": 1038,
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"score": 0.8333333
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},
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{
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"text": "smerch",
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"freq": 3,
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"score": 0.8333333
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},
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{
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"text": "serch",
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"freq": 2,
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"score": 0.8
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}
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]
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},
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{
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"text": "engies",
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"offset": 27,
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"length": 6,
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"options": [
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{
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"text": "engines",
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"freq": 568,
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"score": 0.8333333
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},
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{
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"text": "engles",
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"freq": 3,
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"score": 0.8333333
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},
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{
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"text": "eggies",
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"freq": 1,
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"score": 0.8333333
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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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}
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--------------------------------------------------
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include::suggesters/term-suggest.asciidoc[]
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include::suggesters/phrase-suggest.asciidoc[]
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include::suggesters/completion-suggest.asciidoc[]
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