Asking for significant terms but returns nothing

Asking for significant terms but returns nothing

I am having an issue with Elasticsearch (version 2.0), I am trying to get the significant terms from a bunch of documents but it always returns nothing.
Here is the schema of my index :
{
“documents” : {
“warmers” : {},
“mappings” : {
“document” : {
“properties” : {
“text” : {
“index” : “not_analyzed”,
“type” : “string”
},
“entities”: {
“properties”: {
“text”: {
“index”: “not_analyzed”,
“type”: “string”
}
}
}
}
}
},
“settings” : {
“index” : {
“creation_date” : “1447410095617”,
“uuid” : “h2m2J9sJQaCpxvGDI591zg”,
“number_of_replicas” : “1”,
“version” : {
“created” : “2000099”
},
“number_of_shards” : “5”
}
},
“aliases” : {}
}
}

So it’s a simple index that contains the field text, which is not analyzed, and an array entities that will contains dictionnaries with a single field: text, which is not analyzed neither.
What I want to do is to match some of the documents and extracts the most significant terms from the entities associated. For that, I use a wildcard and then an aggregation.
Here is the the request I am sending through curl:
curl -XGET ‘http://localhost:9200/documents/_search’ -d ‘{
“query”: {
“bool”: {
“must”: {“wildcard”: {“text”: “*test*”}}
}
},
“aggregations” : {
“my_significant_terms” : {
“significant_terms” : { “field” : “entities.text” }
}
}
}’

Unfortunately, even if Elasticsearch is hitting on some documents, the buckets of the significant terms aggregation are always empty.
I tried to put analyzed instead of not_analyzed also, but I got the same empty results.
So first, is it relevant to do it this way ?
I am a very beginner to Elasticsearch, so, can you explain me how the significant terms aggregations work ?
And finaly, if it is relevant, why my query isn’t working ?
EDIT: I just saw in the Elasticsearch documentation that the significant terms aggregation need a certain amount of data to become effective, and I just have 163 documents in my index. Could it be that ?

Related:  ElasticSearch 5.5.0: Finding relevant documents

Solutions/Answers:

Solution 1:

the significant terms aggregation need a certain amount of data to
become effective, and I just have 163 documents in my index. Could it
be that ?

Using 1 shard not 5 will help if you have a small number of docs.

Solution 2:

Not sure if it will help. Try to specify

“min_doc_count” : 1

References