Elasticsearch: Exists Query on Binary Field - elasticsearch

Question

I am looking for a way to look up the number of documents that has a certain binary field "not set" in a mapped index. However, standard "Exists" query does not seem to work. Example:
{
"some-index": {
"mappings": {
"some-type": {
"properties": {
"data": {
"type": "binary"
}
}
}
}
}
}
Query:
POST http://.../some-index/some-type/_search?size=1
{
"query":{
"exists":{
"field":"data"
}
}
}
The query above would return 0 result no matter what. My guess is this is because Elasticsearch does not store binary fields in source by default, and "Exists" query only looks up the source.
Is there an alternative to using Exists query, ideally without using extra boolean field in mapping?

Answer 1

Does the following do what you want... I'm creating a template with field1 set as binary type, then indexed a document with just field2 (which I didn't bother defining) then I'm searching for docs without field1. You can run these in the Dev Console in Kibana
PUT _template\binary
{
"template": "binary",
"mappings": {
"binary": {
"properties": {
"field1": {
"type": "binary"
}
}
}
}}
PUT /binary/type/1
{
"field2":"abc"
}
GET binary/_search
{
"query": {
"bool": {
"must_not": {
"exists": {
"field": "field1"
}
}
}
}
}
That should return the doc you just indexed... if you change it to the following, it shouldn't return anything because field2 is present!
GET binary/_search
{
"query": {
"bool": {
"must_not": {
"exists": {
"field": "field2"
}
}
}
}
}