# Index 256 out of bounds for length 256
**URL:** https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710
**Category:** Elasticsearch
**Created:** [August 14, 2023, 2:37am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710 "2023-08-14T02:37:44Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@1057888035](https://discuss.elastic.co/u/1057888035)
#### Post date: [August 14, 2023, 2:37am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/1 "2023-08-14T02:37:44Z")
Hi Team,
I am trying to execute api like this in elasticsearch
```auto
GET /_analyze
{
"tokenizer": "keyword",
"char_filter": [
{
"type": "mapping",
"mappings": ["is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data is a test data => test"]
}
],
"text": "heart malignant hemangiopericytoma is a test data"
}
```
echo error: "Index 256 out of bounds for length 256",
This error mabye that the mappings length cannot exceed 256， but my project needs more
---
### Author:  [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)
#### Post date: [August 14, 2023, 5:36am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/2 "2023-08-14T05:36:54Z")
Replacing really long strings is not necessarily what a char filter is designed for. What is the problem you are trying to solve using analysis with this char filter (at a higher level)? Can you please elaborate on the problem and use case and also provide a realistic example of how you want your data analyzed?
---
### Author:  [@1057888035](https://discuss.elastic.co/u/1057888035)
#### Post date: [August 14, 2023, 8:21am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/3 "2023-08-14T08:21:24Z")
I have a project
" **benzylpenicillin allergy**" is a keyword , this equals " **benzyl penicillin allergy**".
Now, there is a text
```auto
POST /index/_doc
{
"text": "benzyl penicillin allergy should not be used in tissues with poor blood flow. If allergic symptoms occur (e.g. skin rash, itching, shortness of breath), tell a doctor immediately . Before treatment, a hypersensitivity test should be performed if possible."
}
```
I want this document ,when I search for " **benzylpenicillin allergy**" .
I use standard analyzer, it will be analyze to "benzylpenicillin, allergy" ，
which is not feasible , be because I still have some document containing "allergy" or "penicillin" .
So, I removed the space between them with the **mappings** , and " **benzylpenicillinallergy**" is equal to " **benzylpenicillinallergy**" use alias filter
Do you have a better way ？ Thanks
---
### Author:  [@1057888035](https://discuss.elastic.co/u/1057888035)
#### Post date: [August 14, 2023, 8:38am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/4 "2023-08-14T08:38:28Z")
more:
" **isoniazide allergy**" is equal to " **inh allergy**" and is equal to " **isonicotinylhydrazide allergy**".
” **superficial mycosis** “ is equal to " **steroid-modified tinea infection**" and is equal to " **piedra**".
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [August 14, 2023, 1:22pm UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/5 "2023-08-14T13:22:55Z")
What about using synonyms?
> **[Boosting the power of Elasticsearch with synonyms](https://www.elastic.co/blog/boosting-the-power-of-elasticsearch-with-synonyms)**
>
> How to use synonyms and synonym filters in Elasticsearch. Synonyms are a powerful tool for increasing the recall of your search system, but there are many subtleties that are important to know and experiment with, especially in conjunction with...
---
### Author:  [@1057888035](https://discuss.elastic.co/u/1057888035)
#### Post date: [August 15, 2023, 3:13am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/6 "2023-08-15T03:13:00Z")
I tried synonyms but it doesn't solve the problem.
It won't work when my synonym contains spaces.
Like this:
analysis/ **synonym.txt**
```auto
thiopental allergy,penthiobarbital allergy,pentothiobarbital allergy
d-mannitol allergy,mannitol allergy
cefotaxime allergy
cephalosporin allergy
amodiaquine allergy,camoquin allergy,flavoquine allergy
```
**The result I want is**
```auto
GET test_index/_analyze
{
"analyzer":"my_analyzer",
"text": "thiopental allergy is a test"
}
result:
{
"tokens": [
{
"token": "thiopental allergy",
"start_offset": 0,
"end_offset": 18,
"type": "word",
"position": 0
},
{
"token": "penthiobarbital allergy",
"start_offset": 0,
"end_offset": 18,
"type": "word",
"position": 0
},
{
"token": "pentothiobarbital allergy",
"start_offset": 0,
"end_offset": 18,
"type": "word",
"position": 0
},
{
"token": "is",
"start_offset": 19,
"end_offset": 21,
"type": "word",
"position": 0
},
{
"token": "a",
"start_offset": 22,
"end_offset": 23,
"type": "word",
"position": 0
},
{
"token": "test",
"start_offset": 24,
"end_offset": 28,
"type": "word",
"position": 0
},
]
}
```
_but, the truth is_
**1. when I use "," tokenizer and synonyms**
```auto
PUT test_index
{
"settings": {
"index": {
"number_of_shards": 5,
"number_of_replicas": 1,
"analysis": {
"analyzer": {
"index_analyzer": {
"tokenizer": "standard",
"filter": ["lowercase"],
"type": "custom"
},
"my_analyzer": {
"tokenizer": "comma",
"filter": ["my_synonym","lowercase"],
"type": "custom"
}
},
"filter": {
"my_synonym": {
"ignore_case": "true",
"expand": "true",
"type": "synonym",
"synonyms_path": "analysis/synonym.txt"
}
},
"tokenizer":{
"comma":{
"type": "pattern",
"pattern":",|，"
}
}
}
}
},
"mappings": {
"properties": {
"abstract": {
"type": "text",
"analyzer": "index_analyzer",
"search_analyzer": "my_analyzer"
}
}
}
}
GET test_index/_analyze
{
"analyzer":"my_analyzer",
"text": "thiopental allergy is a test"
}
```
result:
```auto
{
"tokens": [
{
"token": "thiopental allergy is a test",
"start_offset": 0,
"end_offset": 28,
"type": "word",
"position": 0
}
]
}
```
**2. when I use standard tokenizer and synonyms**
```auto
PUT test_index2
{
"settings": {
"index": {
"number_of_shards": 5,
"number_of_replicas": 1,
"analysis": {
"analyzer": {
"index_analyzer": {
"tokenizer": "standard",
"filter": ["lowercase"],
"type": "custom"
},
"my_analyzer": {
"tokenizer": "standard",
"filter": ["my_synonym","lowercase"],
"type": "custom"
}
},
"filter": {
"my_synonym": {
"ignore_case": "true",
"expand": "true",
"type": "synonym",
"synonyms_path": "analysis/synonymOld.txt"
}
}
}
}
},
"mappings": {
"properties": {
"abstract": {
"type": "text",
"analyzer": "index_analyzer",
"search_analyzer": "my_analyzer"
}
}
}
}
GET test_index2/_analyze
{
"analyzer":"my_analyzer",
"text": "thiopental allergy is a test"
}
```
result
```auto
{
"tokens": [
{
"token": "thiopental",
"start_offset": 0,
"end_offset": 10,
"type": "",
"position": 0
},
{
"token": "penthiobarbital",
"start_offset": 0,
"end_offset": 10,
"type": "SYNONYM",
"position": 0
},
{
"token": "pentothiobarbital",
"start_offset": 0,
"end_offset": 10,
"type": "SYNONYM",
"position": 0
},
{
"token": "allergy",
"start_offset": 11,
"end_offset": 18,
"type": "",
"position": 1
},
{
"token": "allergy",
"start_offset": 11,
"end_offset": 18,
"type": "SYNONYM",
"position": 1
},
{
"token": "allergy",
"start_offset": 11,
"end_offset": 18,
"type": "SYNONYM",
"position": 1
},
{
"token": "is",
"start_offset": 19,
"end_offset": 21,
"type": "",
"position": 2
},
{
"token": "a",
"start_offset": 22,
"end_offset": 23,
"type": "",
"position": 3
},
{
"token": "test",
"start_offset": 24,
"end_offset": 28,
"type": "",
"position": 4
}
]
}
```
Neither of these results met my needs
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [August 15, 2023, 11:01am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/7 "2023-08-15T11:01:34Z")
May be adding [shingles](https://www.elastic.co/guide/en/elasticsearch/reference/current/analysis-shingle-tokenfilter.html) before the synonyms token filter would help?
---
### Author:  [@1057888035](https://discuss.elastic.co/u/1057888035)
#### Post date: [August 17, 2023, 1:52am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/8 "2023-08-17T01:52:57Z")
result this error: **Token filter [shingle] cannot be used to parse synonyms**
```auto
PUT test_index
{
"settings": {
"index": {
"number_of_shards": 5,
"number_of_replicas": 1,
"analysis": {
"analyzer": {
"index_analyzer": {
"tokenizer": "standard",
"type": "custom"
},
"my_analyzer": {
"tokenizer": "whitespace",
"filter": ["shingle","my_synonym"],
"type": "custom"
}
},
"filter": {
"my_synonym": {
"ignore_case": "true",
"expand": "true",
"type": "synonym",
"synonyms_path": "analysis/synonym.txt"
}
}
}
}
},
"mappings": {
"properties": {
"abstract": {
"type": "text",
"analyzer": "index_analyzer",
"search_analyzer": "my_analyzer"
}
}
}
}
```
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 14, 2023, 1:53am UTC](https://discuss.elastic.co/t/index-256-out-of-bounds-for-length-256/340710/9 "2023-09-14T01:53:41Z")
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