203 lines
5.5 KiB
Plaintext
203 lines
5.5 KiB
Plaintext
[[specify-analyzer]]
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=== Specify an analyzer
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{es} offers a variety of ways to specify built-in or custom analyzers:
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* By `text` field, index, or query
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* For <<analysis-index-search-time,index or search time>>
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[TIP]
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.Keep it simple
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====
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The flexibility to specify analyzers at different levels and for different times
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is great... _but only when it's needed_.
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In most cases, a simple approach works best: Specify an analyzer for each
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`text` field, as outlined in <<specify-index-field-analyzer>>.
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This approach works well with {es}'s default behavior, letting you use the same
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analyzer for indexing and search. It also lets you quickly see which analyzer
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applies to which field using the <<indices-get-mapping,get mapping API>>.
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If you don't typically create mappings for your indices, you can use
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<<indices-templates,index templates>> to achieve a similar effect.
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====
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[[specify-index-time-analyzer]]
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==== How {es} determines the index analyzer
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{es} determines which index analyzer to use by checking the following parameters
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in order:
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. The <<analyzer,`analyzer`>> mapping parameter for the field.
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See <<specify-index-field-analyzer>>.
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. The `analysis.analyzer.default` index setting.
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See <<specify-index-time-default-analyzer>>.
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If none of these parameters are specified, the
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<<analysis-standard-analyzer,`standard` analyzer>> is used.
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[[specify-index-field-analyzer]]
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==== Specify the analyzer for a field
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When mapping an index, you can use the <<analyzer,`analyzer`>> mapping parameter
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to specify an analyzer for each `text` field.
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The following <<indices-create-index,create index API>> request sets the
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`whitespace` analyzer as the analyzer for the `title` field.
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[source,console]
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----
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PUT my-index-000001
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{
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"mappings": {
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"properties": {
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"title": {
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"type": "text",
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"analyzer": "whitespace"
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}
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}
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}
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}
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----
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[[specify-index-time-default-analyzer]]
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==== Specify the default analyzer for an index
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In addition to a field-level analyzer, you can set a fallback analyzer for
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using the `analysis.analyzer.default` setting.
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The following <<indices-create-index,create index API>> request sets the
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`simple` analyzer as the fallback analyzer for `my-index-000001`.
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[source,console]
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----
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PUT my-index-000001
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{
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"settings": {
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"analysis": {
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"analyzer": {
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"default": {
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"type": "simple"
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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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[[specify-search-analyzer]]
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==== How {es} determines the search analyzer
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// tag::search-analyzer-warning[]
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[WARNING]
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====
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In most cases, specifying a different search analyzer is unnecessary. Doing so
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could negatively impact relevancy and result in unexpected search results.
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If you choose to specify a separate search analyzer, we recommend you thoroughly
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<<test-analyzer,test your analysis configuration>> before deploying in
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production.
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====
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// end::search-analyzer-warning[]
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At search time, {es} determines which analyzer to use by checking the following
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parameters in order:
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. The <<analyzer,`analyzer`>> parameter in the search query.
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See <<specify-search-query-analyzer>>.
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. The <<search-analyzer,`search_analyzer`>> mapping parameter for the field.
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See <<specify-search-field-analyzer>>.
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. The `analysis.analyzer.default_search` index setting.
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See <<specify-search-default-analyzer>>.
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. The <<analyzer,`analyzer`>> mapping parameter for the field.
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See <<specify-index-field-analyzer>>.
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If none of these parameters are specified, the
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<<analysis-standard-analyzer,`standard` analyzer>> is used.
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[[specify-search-query-analyzer]]
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==== Specify the search analyzer for a query
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When writing a <<full-text-queries,full-text query>>, you can use the `analyzer`
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parameter to specify a search analyzer. If provided, this overrides any other
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search analyzers.
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The following <<search-search,search API>> request sets the `stop` analyzer as
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the search analyzer for a <<query-dsl-match-query,`match`>> query.
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[source,console]
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----
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GET my-index-000001/_search
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{
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"query": {
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"match": {
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"message": {
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"query": "Quick foxes",
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"analyzer": "stop"
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}
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}
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}
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}
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----
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// TEST[s/^/PUT my-index-000001\n/]
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[[specify-search-field-analyzer]]
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==== Specify the search analyzer for a field
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When mapping an index, you can use the <<analyzer,`search_analyzer`>> mapping
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parameter to specify a search analyzer for each `text` field.
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If a search analyzer is provided, the index analyzer must also be specified
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using the `analyzer` parameter.
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The following <<indices-create-index,create index API>> request sets the
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`simple` analyzer as the search analyzer for the `title` field.
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[source,console]
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----
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PUT my-index-000001
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{
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"mappings": {
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"properties": {
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"title": {
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"type": "text",
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"analyzer": "whitespace",
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"search_analyzer": "simple"
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}
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}
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}
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}
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----
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[[specify-search-default-analyzer]]
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==== Specify the default search analyzer for an index
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When <<indices-create-index,creating an index>>, you can set a default search
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analyzer using the `analysis.analyzer.default_search` setting.
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If a search analyzer is provided, a default index analyzer must also be
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specified using the `analysis.analyzer.default` setting.
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The following <<indices-create-index,create index API>> request sets the
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`whitespace` analyzer as the default search analyzer for the `my-index-000001` index.
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[source,console]
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----
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PUT my-index-000001
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{
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"settings": {
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"analysis": {
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"analyzer": {
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"default": {
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"type": "simple"
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},
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"default_search": {
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"type": "whitespace"
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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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