I'm trying to do case-insensitive aggregation in a keyword type field, but I am having problems getting this to work.
What I have tried so far is to add a custom parser called "lower case", which uses the "keyword" tokenizer and the "lower case" filter. Then I added a field for display called "use_lowercase" for the field I want to work with. I wanted to keep the existing components of the text and keyword fields, since I can search for terms in the field.
Here is the definition of the index, including a custom parser:
PUT authors
{
"settings": {
"analysis": {
"analyzer": {
"lowercase": {
"type": "custom",
"tokenizer": "keyword",
"filter": "lowercase"
}
}
}
},
"mappings": {
"famousbooks": {
"properties": {
"Author": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
},
"use_lowercase": {
"type": "text",
"analyzer": "lowercase"
}
}
}
}
}
}
}
Now I am adding 2 entries with the same Author, but with a different case:
POST authors/famousbooks/1
{
"Book": "The Mysterious Affair at Styles",
"Year": 1920,
"Price": 5.92,
"Genre": "Crime Novel",
"Author": "Agatha Christie"
}
POST authors/famousbooks/2
{
"Book": "And Then There Were None",
"Year": 1939,
"Price": 6.99,
"Genre": "Mystery Novel",
"Author": "Agatha christie"
}
. , ,
GET authors/famousbooks/_search
{
"size": 0,
"aggs": {
"authors-aggs": {
"terms": {
"field": "Author.use_lowercase"
}
}
}
}
:
{
"error": {
"root_cause": [
{
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [Author.use_lowercase] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
],
"type": "search_phase_execution_exception",
"reason": "all shards failed",
"phase": "query",
"grouped": true,
"failed_shards": [
{
"shard": 0,
"index": "authors",
"node": "yxcoq_eKRL2r6JGDkshjxg",
"reason": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [Author.use_lowercase] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
}
],
"caused_by": {
"type": "illegal_argument_exception",
"reason": "Fielddata is disabled on text fields by default. Set fielddata=true on [Author.use_lowercase] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory."
}
},
"status": 400
}
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