Weird Results with Pattern Analyzer

[vveluchamy (Vasanthakumar)]

Hello,

We have the following Tokenizers

"tokenizer": {
"starts_with_tokenizer": {
"type": "edge_ngram",
"min_gram": "1",
"max_gram": "10"
},
"ngrams_tokenizer": {
"token_chars": [
"letter",
"digit"
],
"min_gram": "1",
"type": "edge_ngram",
"max_gram": "10"
}
}

We have the following analyzers

"analyzer": {
"ngrams_analyzer": {
"filter": [
"lowercase"
],
"type": "custom",
"tokenizer": "ngrams_tokenizer"
},
"starts_with_analyzer": {
"filter": [
"lowercase"
],
"type": "custom",
"tokenizer": "starts_with_tokenizer"
},
"keyword_lowercase_analyzer": {
"filter": [
"lowercase"
],
"type": "custom",
"tokenizer": "keyword"
},
"alphanumeric_analyzer": {
"lowercase": "true",
"pattern": "[^a-zA-Z0-9áéíñóúüÁÉÍÑÓÚÜàâäôéèëêïîçùûüÿæœÀÂÄÔÉÈËÊÏΟÇÙÛÜÆŒäöüßÄÖÜẞàèéìíîòóùúÀÈÉÌÍÎÒÓÙÚ]",
"type": "pattern"
}
}

And we have the following mappings

"fileName": {
"type": "text",
"fields": {
"alphanumeric": {
"analyzer": "alphanumeric_analyzer",
"type": "text"
},
"lowercase": {
"analyzer": "keyword_lowercase_analyzer",
"type": "text"
},
"ngrams": {
"analyzer": "ngrams_analyzer",
"type": "text"
},
"keyword": {
"type": "keyword"
},
"starts_with": {
"analyzer": "starts_with_analyzer",
"type": "text"
}
}
}

We indexed the below file name

RBK-CAT-CAT=CN6468_P20z1_ab44_01.jpg

Scenario 1
For the scenario, the below query returns results
{
"timeout": "1m",
"from": 0,
"size": 12,
"sort": [
{
"sortKey": {
"order": "asc"
}
}
],
"query": {
"bool": {
"filter": [
{
"bool": {
"must": [
{
"terms": {
"jobFolderID": [
1316539,
1317448
]
}
},
{
"bool": {
"should": [
{
"bool": {
"must": [
{
"match": {
"fileName.ngrams": {
"query": "rbk",
"operator": "and"
}
}
},
{
"match": {
"fileName.ngrams": {
"query": "cat",
"operator": "and"
}
}
},
{
"match": {
"fileName.ngrams": {
"query": "cat",
"operator": "and"
}
}
},
{
"match": {
"fileName.alphanumeric": {
"type": "phrase_prefix",
"query": "cn6468_p20z1_ab44"
}
}
}
]
}
}
]
}
}
]
}
}
]
}
}
}

However, the below query does not return any result

{
"timeout": "1m",
"from": 0,
"size": 12,
"sort": [
{
"sortKey": {
"order": "asc"
}
}
],
"query": {
"bool": {
"filter": [
{
"bool": {
"must": [
{
"terms": {
"jobFolderID": [
1316539,
1317448
]
}
},
{
"bool": {
"should": [
{
"bool": {
"must": [
{
"match": {
"fileName.ngrams": {
"query": "rbk",
"operator": "and"
}
}
},
{
"match": {
"fileName.ngrams": {
"query": "cat",
"operator": "and"
}
}
},
{
"match": {
"fileName.ngrams": {
"query": "cat",
"operator": "and"
}
}
},
{
"match": {
"fileName.alphanumeric": {
"type": "phrase_prefix",
"query": "cn6468_p20z1_ab4"
}
}
}
]
}
}
]
}
}
]
}
}
]
}
}
}

Scenario 2
Some of the sample phrase_prefix queries that do not return results are

"match": {
"fileName.alphanumeric": {
"type": "phrase_prefix",
"query": "cn6468_p20z1_ab"
}
}

"match": {
"fileName.alphanumeric": {
"type": "phrase_prefix",
"query": "cn6468_p20z1_a"
}
}

Question

1. How this actually works?
2. Why I do not get some of the search-as-you-type type of queries?

Please help me to understand how this fileName.alphanumeric query works.

Thanks in advance.