Post filter on subaggregation in elasticsearch - elasticsearch

Question

I am trying to run a post filter on the aggregated data, but it is not working as i expected. Can someone review my query and suggest if i am doing anything wrong here.
"query" : {
"bool" : {
"must" : {
"range" : {
"versionDate" : {
"from" : null,
"to" : "2016-04-22T23:13:50.000Z",
"include_lower" : false,
"include_upper" : true
}
}
}
}
},
"aggregations" : {
"associations" : {
"terms" : {
"field" : "association.id",
"size" : 0,
"order" : {
"_term" : "asc"
}
},
"aggregations" : {
"top" : {
"top_hits" : {
"from" : 0,
"size" : 1,
"_source" : {
"includes" : [ ],
"excludes" : [ ]
},
"sort" : [ {
"versionDate" : {
"order" : "desc"
}
} ]
}
},
"disabledDate" : {
"filter" : {
"missing" : {
"field" : "disabledDate"
}
}
}
}
}
}
}
STEPS in the query:
Filter by indexDate less than or equal to a given date.
Aggregate based on formId. Forming buckets per formId.
Sort in descending order and return top hit result per bucket.
Run a subaggregation filter after the sort subaggregation and remove all the documents from buckets where disabled date is not null.(Which is not working)

Answer 1

The whole purpose of post_filter is to run after aggregations have been computed. As such, post_filter has no effect whatsoever on aggregation results.
What you can do in your case is to apply a top-level filter aggregation so that documents with no disabledDate are not taken into account in aggregations, i.e. consider only documents with disabledDate.
{
"query": {
"bool": {
"must": {
"range": {
"versionDate": {
"from": null,
"to": "2016-04-22T23:13:50.000Z",
"include_lower": true,
"include_upper": true
}
}
}
}
},
"aggregations": {
"with_disabled": {
"filter": {
"exists": {
"field": "disabledDate"
}
},
"aggs": {
"form.id": {
"terms": {
"field": "form.id",
"size": 0
},
"aggregations": {
"top": {
"top_hits": {
"size": 1,
"_source": {
"includes": [],
"excludes": []
},
"sort": [
{
"versionDate": {
"order": "desc"
}
}
]
}
}
}
}
}
}
}
}