Get data on several elements from both parent and child in one elasticsearch request

Question

Is it possible to get field data from parent and child in one elasticsearch request? Essentially, I am trying to capture data for multiple parent fields and multiple child fields in the same iteration with filtering. I tried various methods of binding information to a single request, but could not figure out how to do this. Here is what my comparison looks like: -

Parent:

_id_parent : values {1} _source: {_date (20160316), _time (20160316010000), _id_source (test), _year (2016), _month (1)} 

child:

 _id_child : values {1} _source: {_id_child (1), _id_parent (1), _child_question (q1), _child_answer (This needs to be done.)} 

Expected Result (something similar below):

  (PARENT) "hits" : { "total" : 1, "max_score" : 1.0, "hits" : [ { "_index" : "index", "_type" : "parent", "_id" : "1", "_score" : 1.0, "_source":{_id_parent":"1","_id_source":"test","_date":"20160316","_time":"20160316010000","_year":2016,"_month":"1"} } ] } (CHILD) "hits" : { "total" : 1, "max_score" : 1.0, "hits" : [ { "_index" : "index", "_type" : "child", "_id" : "1", "_score" : 1.0, "_source":{"_id_child":"1", "_child_question":"q1","_child_answer":"This needs to be done."} } ] } 

References:

http://rore.im/posts/elasticsearch-joins/

https://github.com/elastic/elasticsearch/issues/761

https://www.elastic.co/guide/en/elasticsearch/guide/current/children-agg.html

  curl -XGET "$ELASTICSEARCH_ENDPOINT/index/parent/_search?pretty=true" -d " { "query": { "match": { "_id_parent": "1" } }, "size" : 10, "aggs": { "_id_parent": { "terms": { "field":"_id_parent", "field":"_id_source", "field":"_date", "field":"_time", "field":"_year", "field":"_month", }, "aggs": { "child": { "children": { "type": "child" }, "aggs": { "child": { "terms": { "field": "child._id_child", "field": "child._child_question", "field": "child._child_answer", } } } } } } } }" 

Answer 1

I made some assumptions ... let me know if they are correct

• You want the document from the parent map to have the document id = 1
• You also need all child documents that have parent_id = 1
• You pass this parent_id from your code to elasticsearch.
• You do not request elasticsearch to filter through multiple parent documents. Before you click elasticsearch, you already know that you want to get the parent document with id = 1

If so, you can create two separate queries

The first request is "get parent document with id = 1"
Second request: "get all child documents with parent_id = 1"

And you can use the Elasticsearch multi-user search API to send both of these requests to elasticsearch in one network call

MultiSearch API

Answer 2

It sounds like work for domestic hits . This function allows you to get hits that have a has_child or has_parent .

In your case, you will make a request against the parent with a trivial has_child (i.e. match_all) or vice versa, for example, something like

 { "query" : { "has_child" : { "type" : "child", "query" : { "match_all": {} }, "inner_hits" : {} } } } 

Answer 3

You can use the example below to search by parent and child index. Hope this helps you.

  GET indexname/_search { "query": { "bool": { "must": [ { "bool": { "must": [ { "term": { "parentField": { "value": "valuetosearch" } } } ] } }, { "has_child": { "type": "childindex", "query": { "range" : { "childindexField" : { "lte": "value" } } } } } ] } } }