91 lines
2.3 KiB
Plaintext
91 lines
2.3 KiB
Plaintext
[[position-increment-gap]]
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=== `position_increment_gap`
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<<mapping-index,Analyzed>> string fields take term <<index-options,positions>>
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into account, in order to be able to support
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<<query-dsl-match-query-phrase,proximity or phrase queries>>.
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When indexing string fields with multiple values a "fake" gap is added between
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the values to prevent most phrase queries from matching across the values. The
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size of this gap is configured using `position_increment_gap` and defaults to
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`100`.
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For example:
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[source,js]
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--------------------------------------------------
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PUT /my_index/groups/1
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{
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"names": [ "John Abraham", "Lincoln Smith"]
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}
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GET /my_index/groups/_search
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{
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"query": {
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"match_phrase": {
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"names": {
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"query": "Abraham Lincoln" <1>
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}
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}
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}
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}
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GET /my_index/groups/_search
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{
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"query": {
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"match_phrase": {
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"names": {
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"query": "Abraham Lincoln",
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"slop": 101 <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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// AUTOSENSE
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<1> This phrase query doesn't match our document which is totally expected.
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<2> This phrase query matches our document, even though `Abraham` and `Lincoln`
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are in separate strings, because `slop` > `position_increment_gap`.
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The `position_increment_gap` can be specified in the mapping. For instance:
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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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"groups": {
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"properties": {
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"names": {
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"type": "string",
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"position_increment_gap": 0 <1>
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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/groups/1
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{
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"names": [ "John Abraham", "Lincoln Smith"]
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}
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GET /my_index/groups/_search
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{
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"query": {
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"match_phrase": {
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"names": "Abraham Lincoln" <2>
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}
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}
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}
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--------------------------------------------------
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// AUTOSENSE
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<1> The first term in the next array element will be 0 terms apart from the
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last term in the previous array element.
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<2> The phrase query matches our document which is weird, but its what we asked
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for in the mapping.
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TIP: The `position_increment_gap` setting is allowed to have different settings
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for fields of the same name in the same index. Its value can be updated on
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existing fields using the <<indices-put-mapping,PUT mapping API>>.
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