diff --git a/_analyzers/token-filters/index.md b/_analyzers/token-filters/index.md index 040397424b..07e00dd466 100644 --- a/_analyzers/token-filters/index.md +++ b/_analyzers/token-filters/index.md @@ -39,7 +39,7 @@ Token filter | Underlying Lucene token filter| Description `kstem` | [KStemFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/en/KStemFilter.html) | Provides kstem-based stemming for the English language. Combines algorithmic stemming with a built-in dictionary. `kuromoji_completion` | [JapaneseCompletionFilter](https://lucene.apache.org/core/9_10_0/analysis/kuromoji/org/apache/lucene/analysis/ja/JapaneseCompletionFilter.html) | Adds Japanese romanized terms to the token stream (in addition to the original tokens). Usually used to support autocomplete on Japanese search terms. Note that the filter has a `mode` parameter, which should be set to `index` when used in an index analyzer and `query` when used in a search analyzer. Requires the `analysis-kuromoji` plugin. For information about installing the plugin, see [Additional plugins]({{site.url}}{{site.baseurl}}/install-and-configure/plugins/#additional-plugins). [`length`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/length/) | [LengthFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LengthFilter.html) | Removes tokens that are shorter or longer than the length range specified by `min` and `max`. -`limit` | [LimitTokenCountFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LimitTokenCountFilter.html) | Limits the number of output tokens. A common use case is to limit the size of document field values based on token count. +[`limit`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/limit/) | [LimitTokenCountFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/miscellaneous/LimitTokenCountFilter.html) | Limits the number of output tokens. For example, document field value sizes can be limited based on the token count. [`lowercase`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/lowercase/) | [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) | Converts tokens to lowercase. The default [LowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/core/LowerCaseFilter.html) processes the English language. To process other languages, set the `language` parameter to `greek` (uses [GreekLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/el/GreekLowerCaseFilter.html)), `irish` (uses [IrishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/ga/IrishLowerCaseFilter.html)), or `turkish` (uses [TurkishLowerCaseFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/tr/TurkishLowerCaseFilter.html)). [`min_hash`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/min-hash/) | [MinHashFilter](https://lucene.apache.org/core/9_10_0/analysis/common/org/apache/lucene/analysis/minhash/MinHashFilter.html) | Uses the [MinHash technique](https://en.wikipedia.org/wiki/MinHash) to estimate document similarity. Performs the following operations on a token stream sequentially:
1. Hashes each token in the stream.
2. Assigns the hashes to buckets, keeping only the smallest hashes of each bucket.
3. Outputs the smallest hash from each bucket as a token stream. [`multiplexer`]({{site.url}}{{site.baseurl}}/analyzers/token-filters/multiplexer/) | N/A | Emits multiple tokens at the same position. Runs each token through each of the specified filter lists separately and outputs the results as separate tokens. diff --git a/_analyzers/token-filters/limit.md b/_analyzers/token-filters/limit.md new file mode 100644 index 0000000000..a849f5f06b --- /dev/null +++ b/_analyzers/token-filters/limit.md @@ -0,0 +1,89 @@ +--- +layout: default +title: Limit +parent: Token filters +nav_order: 250 +--- + +# Limit token filter + +The `limit` token filter is used to limit the number of tokens passed through the analysis chain. + +## Parameters + +The `limit` token filter can be configured with the following parameters. + +Parameter | Required/Optional | Data type | Description +:--- | :--- | :--- | :--- +`max_token_count` | Optional | Integer | The maximum number of tokens to be generated. Default is `1`. +`consume_all_tokens` | Optional | Boolean | (Expert-level setting) Uses all tokens from the tokenizer, even if the result exceeds `max_token_count`. When this parameter is set, the output still only contains the number of tokens specified by `max_token_count`. However, all tokens generated by the tokenizer are processed. Default is `false`. + +## Example + +The following example request creates a new index named `my_index` and configures an analyzer with a `limit` filter: + +```json +PUT my_index +{ + "settings": { + "analysis": { + "analyzer": { + "three_token_limit": { + "tokenizer": "standard", + "filter": [ "custom_token_limit" ] + } + }, + "filter": { + "custom_token_limit": { + "type": "limit", + "max_token_count": 3 + } + } + } + } +} +``` +{% include copy-curl.html %} + +## Generated tokens + +Use the following request to examine the tokens generated using the analyzer: + +```json +GET /my_index/_analyze +{ + "analyzer": "three_token_limit", + "text": "OpenSearch is a powerful and flexible search engine." +} +``` +{% include copy-curl.html %} + +The response contains the generated tokens: + +```json +{ + "tokens": [ + { + "token": "OpenSearch", + "start_offset": 0, + "end_offset": 10, + "type": "", + "position": 0 + }, + { + "token": "is", + "start_offset": 11, + "end_offset": 13, + "type": "", + "position": 1 + }, + { + "token": "a", + "start_offset": 14, + "end_offset": 15, + "type": "", + "position": 2 + } + ] +} +```