Semantic text highlighting not returned for flat quantization options #131443
Description
Elasticsearch Version
Serverless
Installed Plugins
No response
Java Version
bundled
OS Version
Serverless
Problem Description
When performing semantic highlighting on a semantic_text field with flat, int4_flat or int8_flat quantization, the semantic highlighter does not return results. Highlighting is returned with default or specified HNSW quantization.
Steps to Reproduce
DELETE test-index
PUT test-index
{
"mappings": {
"properties": {
"body_content_e5": {
"type": "semantic_text",
"inference_id": ".multilingual-e5-small-elasticsearch",
"index_options": {
"dense_vector": {
"type": "int4_hnsw",
"confidence_interval": 0
}
}
}
}
}
}
PUT test-index/_doc/1
{
"body_content_e5": "Elasticsearch is an open source, distributed, RESTful, search engine which is built on top of Lucene internally and enjoys all the features it provides."
}
get test-index/_search
{
"highlight": {
"fields": {
"body_content_e5": {
"number_of_fragments": 1,
"order": "score",
"type": "semantic"
}
}
},
"fields": [
"_inference_fields"
],
"retriever": {
"standard": {
"query": {
"semantic": {
"field": "body_content_e5",
"query": "What is Elasticsearch?"
}
}
}
}
}
Logs (if relevant)
No response