ElasticSearch multimatch substring search - elasticsearch

Question

I have to combine two filters to match requirements:
- a specific list of values in r.status field
- one of the multiple text fields contains the value.
Result query (with using Nest, but it doesn't matter) looks like:
{
"query": {
"bool": {
"filter": [
{
"bool": {
"must": [
{
"term": {
"isActive": {
"value": true
}
}
},
{
"nested": {
"query": {
"bool": {
"must": [
{
"terms": {
"r.status": [
"VALUE_1",
"VALUE_2",
"VALUE_3"
]
}
},
{
"bool": {
"should": [
{
"match": {
"r.g.firstName": {
"type": "phrase",
"query": "SUBSTRING_VALUE"
}
}
},
{
"match": {
"r.g.lastName": {
"type": "phrase",
"query": "SUBSTRING_VALUE"
}
}
}
]
}
}
]
}
},
"path": "r"
}
}
]
}
}
]
}
}
}
Also tried with multi_match query:
{
"query": {
"bool": {
"filter": [
{
"bool": {
"must": [
{
"term": {
"isActive": {
"value": true
}
}
},
{
"nested": {
"query": {
"bool": {
"must": [
{
"terms": {
"r.status": [
"VALUE_1",
"VALUE_2",
"VALUE_3"
]
}
},
{
"multi_match": {
"query": "SUBSTRING_VALUE",
"fields": [
"r.g.firstName",
"r.g.lastName"
]
}
}
]
}
},
"path": "r"
}
}
]
}
}
]
}
}
}
FirstName and LastName are configured in index mappings as text:
"firstName": {
"type": "text"
},
"lastName": {
"type": "text"
}
Elastic gives a lot of full-text search options: multi_match, phrase, wildcards etc. But all of them fail in my case looking a sub-string in my text fields. (terms query and isActive one work well, I just tried to run only them).
What options do I have also or maybe where I made a mistake?
UPD: Combined wildcards worked for me, but such query looks ugly. Looking for a more elegant solution.

Answer 1

The elasticsearch way is to use ngram tokenizer.
The ngram analyzer will split your terms with a sliding window. For example, the input "Hello World" will generate the following terms:
Hel
Hell
Hello
ell
ello
...
Wor
World
orl
...
You can configure the minimum and maximum size of the sliding window (in the example the minimum size is 3). Once the sub terms are generated you can use a match query an the subfield.
Another point, it is weird to use must within a filter. If you are interested in the score, you should always use must otherwise use filter. Read this article for a good understanding.