missing filter issue

gistfile1.sh

echo -e "delete index..."
curl -XDELETE "http://localhost:5028/test"
echo -e "\ncreate index..."
curl -XPUT "http://localhost:5028/test" -d '
{
    "settings": {
        "index": {
            "number_of_shards": 5,
            "number_of_replicas": 0,
            "analysis": {   
                "analyzer": {
                   
                },
                "filter": {
                }
            }
        }
    },
    "mappings": {
        "main": {
            "properties": {
                "name": { "type": "string", "index": "analyzed", "analyzer": "standard", "include_in_all": true}
            }
        }
    }
}
'
echo -e "\npush doc..."
curl -XPOST "http://localhost:5028/test/main" -d '{"name": ""}'
curl -XPOST "http://localhost:5028/test/main" -d '{"name": "22"}'
curl -XPOST "http://localhost:5028/test/main" -d '{"name": null}'
echo -e "\nsearch..."
sleep 2
 
curl -XPOST "http://localhost:5028/test/main/_search" -d '{"query": {"filtered": {"filter": {"missing": {"existence": true, "field": "name", "null_value": true}}}}}'