Finding exact value with synonym applied in elasticsearch - elasticsearch

Question

I have synonym set up for certain fields, however I would like it to be applied to fields I map to not_analyzed.
For example I have field foo storing seksyen 10 which is not_analyzed, and a synonym entry is added for seksyen, section (dealing with mixed languages within a document).
'foo': {'type': 'string', 'index': 'not_analyzed'}
Suppose user issue a query
{"term": {"foo": "section 10"}}
and is expecting foo with seksyen 10 and section 10. However, with the current mapping I can't return seksyen 10 given the query. Also I am doing a filtered query here because I don't want these to be returned
whatever seksyen 10
seksyen 10, something
whatever section 10 something
I just want synonym expansion to be applied to the query, without it specified in the query. How should I do that?

Answer 1

First of all, using term will not do any analysis on the searched text, so you need a different type of query.
You can do it like the following:
{
"mappings": {
"test": {
"properties": {
"foo": {
"type": "string",
"index": "not_analyzed",
"search_analyzer": "synonym"
}
}
}
},
"settings": {
"analysis": {
"analyzer": {
"synonym": {
"tokenizer": "whitespace",
"filter": [
"synonym"
]
}
},
"filter": {
"synonym": {
"type": "synonym",
"synonyms": [
"seksyen, section"
]
}
}
}
}
}
So, you define a search_analyzer to be used at search time only. And then you need to give up on term filter otherwise it will not work:
{
"query": {
"match": {
"foo": "section"
}
}
}
The solution above works in ES 1.x. In ES 2.x the search_analyzer and a not_analyzed field will not be possible anymore.