Nested ElasticSearch query results in too many items - elasticsearch

Question

The nested ElasticSearch query below returns some results it should not hit. A lot of results do not contain the requested order number but are listed nevertheless. I'm not getting all documents though so the query is definitely reducing the result set on some level.
{
"query": {
"nested": {
"path": "orders",
"query": {
"match": {
"orderNumber": "242347"
}
}
}
}
}
The query result (truncated):
{
"took":0,
"timed_out":false,
"_shards": {
"total":1,
"successful":1,
"failed":0
},
"hits": {
"total":60,
"max_score":9.656103,
"hits":[
{
"_index": "index1",
"_type":"documenttype1",
"_id":"mUmudQrVSC6rn68ujDJ8iA",
"_score":9.656103,
"_source" : {
"documentId": 12093894,
"orders": [
{
"customerId": 129048669,
"orderNumber": "242347", // <-- CORRECT HIT ON ORDER
},
{
"customerId": 229405848,
"orderNumber": "431962"
}
]
}
},
{
"_index":"index1",
"_type":"documenttype1",
"_id":"9iO5QBCpT_6kmH3CoBTdWw",
"_score":9.656103,
"_source" : {
"documentId": 43390283,
// <-- ORDER ISN'T HERE BUT THE DOCUMENT IS HIT NEVERTHELESS!
"orders": [
{
"customerId": 229405848,
"orderNumber": "431962"
},
{
"customerId": 129408979,
"orderNumber": "142701"
}
]
}
}
// Left out 58 more results most of which do not contain
// the requested order number.
]
}
}
As you can see, there is a hit (actually, there are quite a few of them) that shouldn't be there because none of the orders contain the requested order number.
This is the mapping for documenttype1:
{
"index1":{
"properties":{
"documentId":{
"type":"integer"
},
"orders":{
"type":"nested",
"properties":{
"customerId":{
"type":"integer"
},
"orderNumber":{
"type":"string",
"analyzer":"custom_internal_code"
}
}
}
}
}
}
Finally, here are the settings to clarify the custom_internal_code analyzer as referred to in the mapping shown above:
{
"index1":{
"settings":{
"index.analysis.analyzer.custom_internal_code.filter.1":"asciifolding",
"index.analysis.analyzer.custom_internal_code.type":"custom",
"index.analysis.analyzer.custom_internal_code.filter.0":"lowercase",
"index.analysis.analyzer.custom_internal_code.tokenizer":"keyword",
}
}
}

Answer 1

for a exact search use termquery [1] and make orderNumber not_analyzed [2].
[1]
http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-term-query.html#query-dsl-term-query
[2]
http://www.elasticsearch.org/guide/en/elasticsearch/guide/current/mapping-intro.html#_literal_index_literal

Answer 2

It seems that you should use bool query instead of match.
But. If you want just filter your records, your should use nested filter instead of query. It works faster, because you have not to calculate scores.
http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-nested-filter.html
{
"query": {
"filtered": {
"query": {
"match_all": {}
},
"filter": {
"nested": {
"path": "orders",
"filter": {
"bool": {
"must": [
{
"term": {
"orderNumber": "242347"
}
}
]
}
},
"_cache": true
}
}
}
}
}