Given the ElasticSearch document below:
{
"_id": "3330481",
"_type": "user",
"_source": {
"id": "3330481",
"following": ["1", "2", "3", ... , "15000"]
}
}
For a given user list ["50", "51", "52"] I want to check which ones are followed by the user with id 3330481. Since she is following 15000 users, I don't want to get the whole list and then check it locally.
Is there any way to retrieve only the relevant users?
I am not sure whether you can fetch a sub-array from a doc.
However, one way of achieving this is by using nested fields. You can change the schema of following field to be nested as below.
{
"id": "3330481",
"following": [
{"userId":"1"}, {"userId":"2"},{"userId": "3"}, ... ]
}
Then you can use inner_hits to retrieve your matching elements in the array as below.
{
"query" : {
"nested" : {
"path" : "following",
"query" : {
"terms" : {"following.userId" : ["50","51","53"]}
},
"inner_hits" : {
"size":0 // fetches all
}
}
}
}
if you just want to retrieve all user's flollowing with ["50", "51", "52"] without affect score, you can use minimum_should_match with bool query. Example:
{
"query" : {
"filtered" : {
"filter" : {
"bool": {
"must": {
"terms": {
"following": ["50", "51", "52"],
"minimum_should_match": 3
}
}
}
}
}
}
}
