ElasticSearch Highlighting fails on match queries against index with Ngram Analyzer - search

Question

I have created an index with ngram analyzer set on all fields in the index and custom _all. After indexing few documents, I am trying to query against the index to have suggestion like feature.
The output of the query does return results but they are not highlighted.
Analyzer Settings:
"analysis": {
"analyzer": {
"my_edgegram_analyzer": {
"filter": [
"lowercase"
],
"tokenizer": "my_edge_tokenizer"
}
},
"tokenizer": {
"my_edge_tokenizer": {
"token_chars": [
"letter",
"digit",
"punctuation",
"symbol"
],
"min_gram": "3",
"type": "ngram",
"max_gram": "26"
}
}
}
Mapping:
{
"st1": {
"mappings": {
"a": {
"_all": {
"enabled": false
},
"dynamic_templates": [
{
"catch_all": {
"match": "imp*",
"match_mapping_type": "string",
"mapping": {
"analyzer": "my_edgegram_analyzer",
"copy_to": "catch_all",
"norms": false,
"type": "text"
}
}
}
],
"properties": {
"catch_all": {
"type": "text",
"store": true,
"analyzer": "my_edgegram_analyzer"
},
"imp_server_id": {
"type": "text",
"norms": false,
"copy_to": [
"catch_all"
],
"analyzer": "my_edgegram_analyzer"
},
"imp_server_name": {
"type": "text",
"norms": false,
"copy_to": [
"catch_all"
],
"analyzer": "my_edgegram_analyzer"
}
}
},
"b": {
"_all": {
"enabled": false
},
"dynamic_templates": [
{
"catch_all": {
"match": "imp*",
"match_mapping_type": "string",
"mapping": {
"analyzer": "my_edgegram_analyzer",
"copy_to": "catch_all",
"norms": false,
"type": "text"
}
}
}
],
"properties": {
"catch_all": {
"type": "text",
"store": true,
"analyzer": "my_edgegram_analyzer"
},
"imp_server_id": {
"type": "text",
"norms": false,
"copy_to": [
"catch_all"
],
"analyzer": "my_edgegram_analyzer"
},
"imp_server_name": {
"type": "text",
"norms": false,
"copy_to": [
"catch_all"
],
"analyzer": "my_edgegram_analyzer"
}
}
}
}
}
}
Documents:
http://localhost:9200/st1/b/1
{"imp_server_name":"abc1-4-jam9.my.test.com","imp_server_id":"vrock2-us"}
http://localhost:9200/st1/a/1
{"imp_server_name":"abc2-5-ajm9.my.test.com","imp_server_id":"vrock2-us"}
Query:
{
"query": {
"match": {
"catch_all": {
"query":"test",
"analyzer": "keyword"
}
}
},
"highlight": {
"pre_tags": ["<b>"],
"post_tags": ["</b>"],
"fields": {
"*": {}
},
"require_field_match": false
}
}
Response:
{
"took": 3,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 2,
"max_score": 0.16292635,
"hits": [
{
"_index": "st1",
"_type": "a",
"_id": "1",
"_score": 0.16292635,
"_source": {
"imp_server_name": "abc2-5-ajm9.my.test.com",
"imp_server_id": "vrock2-us"
},
"highlight": {
"imp_server_name": [
"abc2-5-ajm9.my.test.com"
],
"catch_all": [
"abc2-5-ajm9.my.test.com"
]
}
},
{
"_index": "st1",
"_type": "b",
"_id": "1",
"_score": 0.16292635,
"_source": {
"imp_server_name": "abc1-4-jam9.my.test.com",
"imp_server_id": "vrock2-us"
},
"highlight": {
"imp_server_name": [
"abc1-4-jam9.my.test.com"
],
"catch_all": [
"abc1-4-jam9.my.test.com"
]
}
}
]
}
}
How can I make highlight work in the above scenario. Below is the expected output:
Expected output:
"highlight": {
"imp_server_name": [
"abc2-5-ajm9.my.<b>test</b>.com"
],
"catch_all": [
"abc2-5-ajm9.my.<b>test</b>.com"
]
}

Answer 1

I was able to get the results by setting term_vector in the schema.
"term_vector": "with_positions_offsets"