Using multi-match query in a multi-field does not work - elasticsearch

Question

Our system stores account in the following format: acct:username#domain
But for many searches we only need to username, so for the user created memos I've decided to make the user field a multi_field like this:
{
'text': {
'type': 'string'
}
'user': {
'type': 'multi_field',
'path': 'just_name',
'fields': {
'user': {
'type': 'string',
'index': 'analyzed',
'analyzer': 'lower_keyword'
},
'username': {
'type': 'string',
'index': 'analyzed',
'analyzer': 'username'
}
}
}
}
and other settings:
__settings__ = {
'analysis': {
'tokenizer': {
'username': {
'type': 'pattern',
'group': 1,
'pattern': '^acct:(.+)#.*$'
}
},
'analyzer': {
'lower_keyword': {
'type': 'custom',
'tokenizer': 'keyword',
'filter': 'lowercase'
},
'username': {
'tokenizer': 'username',
'filter': 'lowercase'
}
}
}
}
Now, if I make a query for the username it works. I.e if I have the following user: acct:testuser#testdomain
and I make a query like this:
{
"query": {
"bool": {
"must": [
{
"terms": {
"username": [
"testuser"
]
}
}
],
"minimum_number_should_match": 1
}
},
"size": 50
}
It works (I know it can be done much easier but this is a system generated query).
But, I need to make searches which looks for a string in both the text and the username fields.
I've decided to use a multi-match query for this.
{
"query": {
"bool": {
"must": [
{
"multi_match": {
"operator": "and",
"query": "testuser",
"type": "cross_fields",
"fields": [
"text",
"username"
]
}
}
],
"minimum_number_should_match": 1
}
},
"size": 50
}
Now the problem is, that this query does not work for the username field. It does for the text field, and for other fields if I include them, but does not bring back any result for the username field.
Can you help me what am I doing wrong?

Answer 1

I've forgotten that the username analyzer would also tokenize my searches for match/multi match queries. That way the string 'testuser' was analyzed and it generated zero token.
So the solution is to change the username's field mapping to:
'username': {
'type': 'string',
'index': 'analyzed',
'index_analyzer': 'username',
'search_analyzer': 'lower_keyword'
}
and now both queries are working.