ElasticSearch query with prefix for aggregation - elasticsearch

Question

I am trying to add a prefix condition for my ES query in a "must" clause.
My current query looks something like this:
body = {
"query": {
"bool": {
"must":
{ "term": { "article_lang": 0 }}
,
"filter": {
"range": {
"created_time": {
"gte": "now-3h"
}
}
}
}
},
"aggs": {
"articles": {
"terms": {
"field": "article_id.keyword",
"order": {
"score": "desc"
},
"size": 1000
},
"aggs": {
"score": {
"sum": {
"field": "score"
}
}
}
}
}
}
I need to add a mandatory condition to my query to filter articles whose id starts with "article-".
So, far I have tried this:
{
"query": {
"bool": {
"should": [
{ "term": { "article_lang": 0 }},
{ "prefix": { "article_id": {"value": "article-"} }}
],
"filter": {
"range": {
"created_time": {
"gte": "now-3h"
}
}
}
}
},
"aggs": {
"articles": {
"terms": {
"field": "article_id.keyword",
"order": {
"score": "desc"
},
"size": 1000
},
"aggs": {
"score": {
"sum": {
"field": "score"
}
}
}
}
}
}
I am fairly new to ES and from the documentations online, I know that "should" is to be used for "OR" conditions and "must" for "AND". This is returning me some data but as per the condition it will be consisting of either article_lang=0 or articles starting with article-. When I use "must", it doesn't return anything.
I am certain that there are articles with id starting with this prefix because currently, we are iterating through this result to filter out such articles. What am I missing here?

Answer 1

In your prefix query, you need to use the article_id.keyword field, not article_id. Also, you should prefer filter over must since you're simply doing yes/no matching (aka filters)
{
"query": {
"bool": {
"filter": [ <-- change this
{
"term": {
"article_lang": 0
}
},
{
"prefix": {
"article_id.keyword": { <-- and this
"value": "article-"
}
}
}
],
"filter": {
"range": {
"created_time": {
"gte": "now-3h"
}
}
}
}
},
"aggs": {
"articles": {
"terms": {
"field": "article_id.keyword",
"order": {
"score": "desc"
},
"size": 1000
},
"aggs": {
"score": {
"sum": {
"field": "score"
}
}
}
}
}
}