Ignore "match" clause from query in aggregation - elasticsearch

Question

I have a query with aggregations. One of the aggregation is on the field starsCount. There is a query clause that filters on the starsCount field along with other match clauses (hidden for clarity).
I wish for the starsCount aggregation to ignore the starsCount filtering in its results (the aggregation's result should be as if I had run the same query without the match clause on the starsCount field) while the other aggregation keeps its current behavior
Can this be done in a single query or should I use multiple ?
Here is the (simplified) query:
{
[...]
"aggs": {
"group_by_service": {
"comment": "keep current behaviour",
"terms": {
"field": "services",
"size": 46
}
},
"group_by_stars": {
"comment": "ignore the filter on the starsCount field",
"terms": {
"field": "starsCount",
"size": 100
}
}
},
"query": {
"bool": {
"must": [
[...] filters on other properties, non-relevant
{
"match": {
"starsCount": {
"query": "2"
}
}
}
]
}
}
}

Answer 1

Yes you can achieve this in single query by making use of post filter and filter aggregation.
You need to follow the below steps to create the query:
Remove the starsCount match query from the main query as it should not affect the group_by_stars aggregation.
Since starsCount match query should filter the documents, move it to post_filter. Any query inside post_filter will filter the documents after calculating aggregations.
Now since starsCount is no more part of main query all the aggregations will not be affected by it. But what is required is that this filter should effect all other aggregations except group_by_stars aggregation. To achieve this we'll make use of filter aggregation and apply it to all the aggregations except group_by_stars aggregation.
The resultant query will be as below. (Note that instead of match query I have used term query. You can still use match but in this case term is a better choice.):
{
"aggs": {
"some_other_agg":{
"filter": {
"term": {
"starsCount": "2"
}
},
"aggs": {
"some_other_agg_filtered": {
"terms": {
"field": "some_other_field"
}
}
}
},
"group_by_service": {
"filter": {
"term": {
"starsCount": "2"
}
},
"aggs": {
"group_by_service_filtered": {
"terms": {
"field": "services",
"size": 46
}
}
}
},
"group_by_stars": {
"terms": {
"field": "starsCount",
"size": 100
}
}
},
"query": {
"bool": {
"must": [
{...} //filter on other properties
]
}
},
"post_filter": {
"term": {
"starsCount": "2"
}
}
}