Filter not working for weighted search - elasticsearch

Question

I am pretty new to elasticsearch and have not really got the hold of it. So I have a search, the results of which will be weighed according to the weight of their tags, which works absolutely fine, but later when I introduced a filter, the search always gives me empty results. Here is what I have tried:
{
"nested": {
"path": "tags",
"score_mode": "sum",
"query": {
"function_score": {
"query": {
"bool": {
"must": [
{
"match_phrase_prefix": {
"tags.tag": "big"
}
}
],
"filter": {
"term": {
"type.primary": "audio"
}
}
}
},
"field_value_factor": {
"field": "tags.weight"
},
"boost_mode": "multiply",
"boost": 10
}
}
}
}
The example result with the filter should be something like this:
{
"_index": "assets",
"_type": "Asset",
"_id": "5a1dc3c0848662ee49e36f43s",
"_score": 886.8744,
"_source": {
"name": "And Action Breakbeat",
"meta_data": {
"type": "audio/mp3",
"file_name": "music_zapsplat_and_action_breakbeat.mp3"
},
"file_key": "music_zapsplat_and_action_breakbeat.mp3",
"src": {
"url": "https://exapmle.com/music_zapsplat_and_action_breakbeat.mp3"
},
"type": {
"primary": "AUDIO",
"secondary": "mp3"
},
"thumbnail_url": "https://example.com/thumbnail/audio.jpg",
"tags": [
{
"tag": "big",
"weight": 10
},
{
"tag": "beat",
"weight": 5
},
{
"tag": "music",
"weight": 3.3333333333333335
}
],
"isDeleted": false,
}
}
Thank you!

Answer 1

You cannot match type.primary inside a nested query for tags. Try this query instead:
{
"query": {
"bool": {
"filter": {
"term": {
"type.primary": "audio"
}
},
"must": [
{
"nested": {
"path": "tags",
"query": {
"function_score": {
"query": {
"match_phrase_prefix": {
"tags.tag": "big"
}
},
"field_value_factor": {
"field": "tags.weight"
},
"score_mode": "sum",
"boost_mode": "multiply",
"boost": 10
}
}
}
}
]
}
}
}