# Reindex after adding char\_filter
**URL:** https://discuss.elastic.co/t/reindex-after-adding-char-filter/17905
**Category:** Elasticsearch
**Created:** [June 4, 2014, 12:19pm UTC](https://discuss.elastic.co/t/reindex-after-adding-char-filter/17905 "2014-06-04T12:19:40Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Kirill\_Teplinskiy](https://discuss.elastic.co/u/Kirill_Teplinskiy)
#### Post date: [June 4, 2014, 12:19pm UTC](https://discuss.elastic.co/t/reindex-after-adding-char-filter/17905/1 "2014-06-04T12:19:40Z")
Hello everyone!
I can't understand do I need to reindex documents after adding char\_filter
to existing analyzer or not. My experiment shows char\_filter starts to
work without reindex and this is surprise for me. Can anyone explain how
it works please? Here are steps of my experiment, I use ElasticSearch
0.90.13.
1. Configure analyzer:
test1 :
tokenizer : standard
filter : [lowercase]
1. Add thousand of documents to index:
{"name": "apple 0"}
{"name": "apple 1"}
{"name": "apple 2"}
...
{"name": "apple 999"}
Field "name" is analyzed by analyzer "test1".
1. Add mapping char\_filter to analyzer and restart ElasticSearch. This is
char\_filter configuration:
char\_filter :
ab:
type: mapping
mappings: ["a=\>b"]
1. Query with text "bplle" returns results (and "apple" too)!
{
"query": {
"match": {
"name": "bpple"
}
}
}
Moreover, when I remove char\_filter from analyzer it continues to find
"bplle" but stops find "apple". This confuses me too.
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---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 1:24am UTC](https://discuss.elastic.co/t/reindex-after-adding-char-filter/17905/2 "2017-07-06T01:24:44Z")