must_not doesn't work as NOT

[sanikolaev]

In this case when I have 4 docs like these:

➜  ~ mysql -P9306 -h0 -v -e "drop table if exists test; create table test(a int, b int); insert into test (a, b) values (0, 0),(0,1),(1,0),(1,1)"
--------------
drop table if exists test
--------------

--------------
create table test(a int, b int)
--------------

--------------
insert into test (a, b) values (0, 0),(0,1),(1,0),(1,1)
--------------

and must finds one of them:

➜  ~ curl -sX POST http://localhost:9308/search -d '
{

    "index": "test",
    "query": {
        "bool": {
            "must": [
                {
                    "equals": {
                        "a": 1
                    }
                },
                {
                    "equals": {
                        "b": 1
                    }
                }
            ]
        }
    }
}
'|jq .
{
  "took": 0,
  "timed_out": false,
  "hits": {
    "total": 1,
    "total_relation": "eq",
    "hits": [
      {
        "_id": "1515714768311156772",
        "_score": 1,
        "_source": {
          "a": 1,
          "b": 1
        }
      }
    ]
  }
}

I would expect that if I wrap it into must_not it would act as NOT and would find the other 3 docs, but it's not happening, it finds only one of them:

➜  ~ curl  -sX POST http://localhost:9308/search -d '
{

    "index": "test",
    "query": {
        "bool": {
            "must_not": [
                {
                    "bool": {
                        "must": [
                            {
                                "equals": {
                                    "a": 1
                                }
                            },
                            {
                                "equals": {
                                    "b": 1
                                }
                            }
                        ]
                    }
                }
            ]
        }
    }
}
'|jq .

{
  "took": 0,
  "timed_out": false,
  "hits": {
    "total": 1,
    "total_relation": "eq",
    "hits": [
      {
        "_id": "1515714768311156769",
        "_score": 1,
        "_source": {
          "a": 0,
          "b": 0
        }
      }
    ]
  }
}

Related forum thread: https://forum.manticoresearch.com/t/how-does-must-not-work-in-queries/1782

[tomatolog]

must_not should not work by its own unless searchd.not_terms_only_allowed enabled

[tomatolog]

and for me the must_not query work as it should ( ! ( a==1 AND b==1 ) )