Custom analyzer, use case : zip-code [ElasticSearch] - elasticsearch

Question

Let be a set index/type named customers/customer.
Each document of this set has a zip-code as property.
Basically, a zip-code can be like:
String-String (ex : 8907-1009)
String String (ex : 211-20)
String (ex : 30200)
I'd like to set my index analyzer to get as many documents as possible that could match. Currently, I work like that :
PUT /customers/
{
"mappings":{
"customer":{
"properties":{
"zip-code": {
"type":"string"
"index":"not_analyzed"
}
some string properties ...
}
}
}
When I search a document I'm using that request :
GET /customers/customer/_search
{
"query":{
"prefix":{
"zip-code":"211-20"
}
}
}
That works if you want to search rigourously. But for instance if the zip-code is "200 30", then searching with "200-30" will not give any results.
I'd like to give orders to my index analyser in order to don't have this problem.
Can someone help me ?
Thanks.
P.S. If you want more information, please let me know ;)

Answer 1

As soon as you want to find variations you don't want to use not_analyzed.
Let's try this with a different mapping:
PUT zip
{
"settings": {
"number_of_shards": 1,
"analysis": {
"analyzer": {
"zip_code": {
"tokenizer": "standard",
"filter": [ ]
}
}
}
},
"mappings": {
"_doc": {
"properties": {
"zip": {
"type": "text",
"analyzer": "zip_code"
}
}
}
}
}
We're using the standard tokenizer; strings will be broken up at whitespaces and punctuation marks (including dashes) into tokens. You can see the actual tokens if you run the following query:
POST zip/_analyze
{
"analyzer": "zip_code",
"text": ["8907-1009", "211-20", "30200"]
}
Add your examples:
POST zip/_doc
{
"zip": "8907-1009"
}
POST zip/_doc
{
"zip": "211-20"
}
POST zip/_doc
{
"zip": "30200"
}
Now the query seems to work fine:
GET zip/_search
{
"query": {
"match": {
"zip": "211-20"
}
}
}
This will also work if you just search for "211". However, this might be too lenient, since it will also find "20", "20-211", "211-10",...
What you probably want is a phrase search where all the tokens in your query need to be in the field and also in the right order:
GET zip/_search
{
"query": {
"match_phrase": {
"zip": "211"
}
}
}
Addition:
If the ZIP codes have a hierarchical meaning (if you have "211-20" you want this to be found when searching for "211", but not when searching for "20"), you can use the path_hierarchy tokenizer.
So changing the mapping to this:
PUT zip
{
"settings": {
"number_of_shards": 1,
"analysis": {
"analyzer": {
"zip_code": {
"tokenizer": "zip_tokenizer",
"filter": [ ]
}
},
"tokenizer": {
"zip_tokenizer": {
"type": "path_hierarchy",
"delimiter": "-"
}
}
}
},
"mappings": {
"_doc": {
"properties": {
"zip": {
"type": "text",
"analyzer": "zip_code"
}
}
}
}
}
Using the same 3 documents from above you can use the match query now:
GET zip/_search
{
"query": {
"match": {
"zip": "1009"
}
}
}
"1009" won't find anything, but "8907" or "8907-1009" will.
If you want to also find "1009", but with a lower score, you'll have to analyze the zip code with both variations I have shown (combine the 2 versions of the mapping):
PUT zip
{
"settings": {
"number_of_shards": 1,
"analysis": {
"analyzer": {
"zip_hierarchical": {
"tokenizer": "zip_tokenizer",
"filter": [ ]
},
"zip_standard": {
"tokenizer": "standard",
"filter": [ ]
}
},
"tokenizer": {
"zip_tokenizer": {
"type": "path_hierarchy",
"delimiter": "-"
}
}
}
},
"mappings": {
"_doc": {
"properties": {
"zip": {
"type": "text",
"analyzer": "zip_standard",
"fields": {
"hierarchical": {
"type": "text",
"analyzer": "zip_hierarchical"
}
}
}
}
}
}
}
Add a document with the inverse order to properly test it:
POST zip/_doc
{
"zip": "1009-111"
}
Then search both fields, but boost the one with the hierarchical tokenizer by 3:
GET zip/_search
{
"query": {
"multi_match" : {
"query" : "1009",
"fields" : [ "zip", "zip.hierarchical^3" ]
}
}
}
Then you can see that "1009-111" has a much higher score than "8907-1009".