I want to make query, that returns random documents with probability of each document depends on it weight. In my index each document has weight from 1 to N. So element with weight 1 must appears in result 2 times less, than document with weight 2.
For example I have 3 documents (one with weight 2, two with weight 1). So probability of each document appearance must be 50%, 25%, 25%. Example:
[
{
"_index": "we_recommend_on_main",
"_type": "we_recommend_on_main",
"_id": "5-0",
"_score": 1.1245852,
"_source": {
"id_map_placement": 6151,
"image": "/upload/banner1",
"weight": 2
}
},
{
"_index": "we_recommend_on_main",
"_type": "we_recommend_on_main",
"_id": "8-0",
"_score": 0.14477867,
"_source": {
"id_map_placement": 6151,
"image": "/upload/banner1",
"weight": 1
}
},
{
"_index": "we_recommend_on_main",
"_type": "we_recommend_on_main",
"_id": "8-1",
"_score": 0.0837487,
"_source": {
"id_map_placement": 6151,
"image": "/upload/banner2",
"weight": 1
}
}
]
I found the solution with search like this:
{
"size": 1,
"query": {
"function_score": {
"functions": [
{
"random_score": {}
},
{
"field_value_factor": {
"field": "weight",
"modifier": "none",
"missing": 1
}
}
],
"score_mode": "multiply",
"boost_mode": "replace"
}
},
"sort": [
{
"_score": "desc"
}
]
}
That solution was in issue https://github.com/elastic/elasticsearch/issues/7783#issuecomment-64880008, but it doesn't work as I expected.
After i tested this query with 10000 times result is
{
"5-0": 6730,
"8-1": 1613,
"8-0": 1657
}
But not
{
"5-0": 5000,
"8-1": 2500,
"8-0": 2500
}
I asked this question on stackoverflow, and get answer, that my assumption about probability is wrong https://stackoverflow.com/a/54133955/1848278I understand this, but can't find what query I need to get needed results. Please help me.