Fingerprint analyzer
The fingerprint analyzer creates a text fingerprint. The analyzer sorts and deduplicates the terms (tokens) generated from the input and then concatenates them using a separator. It is commonly used for data deduplication because it produces the same output for similar inputs containing the same words, regardless of word order.
The fingerprint analyzer comprises the following components:
- Standard tokenizer
- Lowercase token filter
- ASCII folding token filter
- Stop token filter
- Fingerprint token filter
Parameters
The fingerprint analyzer can be configured with the following parameters.
| Parameter | Required/Optional | Data type | Description |
|---|---|---|---|
separator | Optional | String | Specifies the character used to concatenate the terms after they have been tokenized, sorted, and deduplicated. Default is an empty space ( ). |
max_output_size | Optional | Integer | Defines the maximum size of the output token. If the concatenated fingerprint exceeds this size, it will be truncated. Default is 255. |
stopwords | Optional | String or list of strings | A custom or predefined list of stopwords. Default is _none_. |
stopwords_path | Optional | String | The path (absolute or relative to the config directory) to the file containing a list of stopwords. |
Example
Use the following command to create an index named my_custom_fingerprint_index with a fingerprint analyzer:
PUT /my_custom_fingerprint_index
{
"settings": {
"analysis": {
"analyzer": {
"my_custom_fingerprint_analyzer": {
"type": "fingerprint",
"separator": "-",
"max_output_size": 50,
"stopwords": ["to", "the", "over", "and"]
}
}
}
},
"mappings": {
"properties": {
"my_field": {
"type": "text",
"analyzer": "my_custom_fingerprint_analyzer"
}
}
}
}
Generated tokens
Use the following request to examine the tokens generated using the analyzer:
POST /my_custom_fingerprint_index/_analyze
{
"analyzer": "my_custom_fingerprint_analyzer",
"text": "The slow turtle swims over to the dog"
}
The response contains the generated tokens:
{
"tokens": [
{
"token": "dog-slow-swims-turtle",
"start_offset": 0,
"end_offset": 37,
"type": "fingerprint",
"position": 0
}
]
}
Further customization
If further customization is needed, you can define an analyzer with additional fingerprint analyzer components:
PUT /custom_fingerprint_analyzer
{
"settings": {
"analysis": {
"analyzer": {
"custom_fingerprint": {
"tokenizer": "standard",
"filter": [
"lowercase",
"asciifolding",
"fingerprint"
]
}
}
}
}
}