Elasticsearch - 使用Bool（MUST＆AND）DSL查询创建报告过滤器

I am trying to create some report filters where the user can search for profiles using any fields on the report. For example: search for any profile with firstname that starts with ann and grade that starts with vi etc.

Here is a query I have written so far:

{
    from: 20,
    size: 20,
    query: {
        filtered: {
            query: {
                match_all: [ ]
            },
            filter: {
                bool: {
                    must: [
                        {
                            prefix: {
                                firstname: "ann"
                            }
                        },
                        {
                            prefix: {
                                grade: "vi"
                            }
                        }
                    ]
                }
            }
       }
   },
   sort: {
       grade: {
           order: "asc"
       }
   }
}

If I remove one child of must (in the bool filter), it works. But it doesn't return any results once I use more than one filters and I need to be able to use any number of entries in there.

Also, if I use should instead of must, it works. I'm not sure if I'm misunderstanding the logic, but to my understanding (in this case) must should return ONLY results with firstname that starts with ann and grade that starts with vi.

They do exist, but this query just doesn't find them.

Am I missing something here?

Thanks

Since, I cannot post comments yet. I'm answering with some assumptions.

First of all, I'm using ES 0.90.2 version and your query works fine for my inputs. However, depending on your input size and the platform that you executed your query, my answer may not be the right one.

Assumption: Number of data in the index is less than 20.

I've added following inputs to my index:

'{"name": "ann", "grade": "vi"}'
'{"name": "ann", "grade": "ii"}'
'{"name": "johan", "grade": "vi"}'
'{"name": "johan", "grade": "ii"}'

And my test query was the same as yours, and here is the result:

"hits" : {
    "total" : 2,
    "max_score" : null,
    "hits" : [ ]          // <-- see this part is blank
  }

As you can see, it didn't listed hits, but there are two hits. That's because of the from:20 code segment. If you change that value, you can see some results. If you want to see all results just delete that part.

Note: Well if this is not the case, sorry for bothering :(