Elasticsearch: simple_query_string and multi-words synonyms - elasticsearch

Question

I have a field with the following search_analyzer:
"name_search_en" : {
"filter" : [
"english_possessive_stemmer",
"lowercase",
"name_synonyms_en",
"english_stop",
"english_stemmer",
"asciifolding"
],
"tokenizer" : "standard"
}
name_synonyms_en is a synonym_graph that looks like this
"name_synonyms_en" : {
"type" : "synonym_graph",
"synonyms" : [
"beach bag => straw bag,beach bag",
"bicycle,bike"
]
}
Running the following multi_match query the synonym are correctly applied
{
"query": {
"multi_match": {
"query": "beach bag",
"auto_generate_synonyms_phrase_query": false,
"type": "cross_fields",
"fields": [
"brand.en-US^1.0",
"name.en-US^1.0"
]
}
}
}
Here is the _validate explanation output. Both beach bag and straw bag are present, as expected, in the raw query:
"explanations" : [
{
"index" : "d7598351-311f-4844-bb91-4f26c9f538f3",
"valid" : true,
"explanation" : "+((((+name.en-US:straw +name.en-US:bag) (+name.en-US:beach +name.en-US:bag))) | (brand.en-US:beach brand.en-US:bag)) #DocValuesFieldExistsQuery [field=_primary_term]"
}
]
I would expect the same in the following simple_query_string
{
"query": {
"simple_query_string": {
"query": "beach bag",
"auto_generate_synonyms_phrase_query": false,
"fields": [
"brand.en-US^1.0",
"name.en-US^1.0"
]
}
}
}
but the straw bag synonym is not present in the raw query
"explanations" : [
{
"index" : "d7598351-311f-4844-bb91-4f26c9f538f3",
"valid" : true,
"explanation" : "+((name.en-US:beach | brand.en-US:beach)~1.0 (name.en-US:bag | brand.en-US:bag)~1.0) #DocValuesFieldExistsQuery [field=_primary_term]"
}
]
The problem seems to be related to multi-terms synonyms only. If I search for bike, the bicycle synonym is correctly present in the query
"explanations" : [
{
"index" : "d7598351-311f-4844-bb91-4f26c9f538f3",
"valid" : true,
"explanation" : "+(Synonym(name.en-US:bicycl name.en-US:bike) | brand.en-US:bike)~1.0 #DocValuesFieldExistsQuery [field=_primary_term]"
}
]
Is this the expected behaviour (meaning multi terms synonyms are not supported for this query)?

Answer 1

By default simple_query_string has the WHITESPACE flag enabled. The input text is tokenized. That's the reason the synonym filter doesn't handle correctly multi-words. This query disable all flags making multi-words synonyms working as expected
{
"query": {
"simple_query_string": {
"query": "beach bag",
"auto_generate_synonyms_phrase_query": false,
"flags": "NONE",
"fields": [
"brand.en-US^1.0",
"name.en-US^1.0"
]
}
}
}
This unfortunately does not play well with minimum_should_match parameter. Full discussion and more details on this can be found here https://discuss.elastic.co/t/simple-query-string-and-multi-terms-synonyms/174780