# Unexpected Behavior with ICU Collation Keyword Sorting

**URL:** <https://discuss.elastic.co/t/unexpected-behavior-with-icu-collation-keyword-sorting/370335>\
**Category:** Elastic Search\
**Created:** [November 11, 2024, 4:33pm UTC](https://discuss.elastic.co/t/unexpected-behavior-with-icu-collation-keyword-sorting/370335 "2024-11-11T16:33:10Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![wolfgang-kammhuber\_c](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/wolfgang-kammhuber_c/32/139110_2.png) [@wolfgang-kammhuber\_c](https://discuss.elastic.co/u/wolfgang-kammhuber_c)\
**Post date:** [November 11, 2024, 4:33pm UTC](https://discuss.elastic.co/t/unexpected-behavior-with-icu-collation-keyword-sorting/370335/1 "2024-11-11T16:33:10Z")

</div>

Hello,

I am experiencing unexpected behavior with the sorting order of documents in Elasticsearch using the `icu_collation_keyword` field type. Here are the details:

### Steps to Reproduce:

1. **Create the Index with Mappings** :  
PUT /test-index  
{  
"mappings": {  
"properties": {  
"id422": {  
"type": "text",  
"fields": {  
"collated": {  
"type": "icu\_collation\_keyword",  
"strength": "tertiary",  
"case\_level": true  
}  
}  
}  
}  
}  
}

2. **Index the Documents** :  
POST /test-index/\_doc/1  
{  
"id422": "0a11"  
}

POST /test-index/\_doc/2  
{  
"id422": "0A11"  
}

POST /test-index/\_doc/3  
{  
"id422": "0b11"  
}

POST /test-index/\_doc/4  
{  
"id422": "0B11"  
}

POST /test-index/\_doc/5  
{  
"id422": "0c11"  
}

POST /test-index/\_doc/6  
{  
"id422": "0C11"  
}

1. **Search and Sort** :

GET /test-index/\_search  
{  
"sort": [  
{  
"id422.collated": {  
"order": "asc"  
}  
}  
],  
"\_source": ["id422"]  
}

### Expected Sort Order:

1. `0A11`
2. `0B11`
3. `0C11`
4. `0a11`
5. `0b11`
6. `0c11`

### Actual Sort Order:

The response includes unexpected characters in the `sort` field, and the order does not match the expected case-sensitive sorting.

### Response:

Sort order  
0a11  
0A11  
0b11  
0B11  
0c11  
0C11

The sort fields of the response contain unexpected cryptic characters like:  
"sort": [  
"""কՅ‡ࡀ

### Additional Information:

- Elasticsearch version: 8.15.3
- Kibana version: 8.15.3
- ICU Analysis plugin version: 8.15.3

Any insights or suggestions on how to resolve this issue would be greatly appreciated.

Thank you!

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 9, 2024, 4:33pm UTC](https://discuss.elastic.co/t/unexpected-behavior-with-icu-collation-keyword-sorting/370335/2 "2024-12-09T16:33:23Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.