# Mutate rename multiple fields, how to improve performance?
**URL:** https://discuss.elastic.co/t/mutate-rename-multiple-fields-how-to-improve-performance/252606
**Category:** Logstash
**Created:** [October 19, 2020, 8:31pm UTC](https://discuss.elastic.co/t/mutate-rename-multiple-fields-how-to-improve-performance/252606 "2020-10-19T20:31:23Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@leandrojmp](https://discuss.elastic.co/u/leandrojmp)
#### Post date: [October 19, 2020, 8:31pm UTC](https://discuss.elastic.co/t/mutate-rename-multiple-fields-how-to-improve-performance/252606/1 "2020-10-19T20:31:23Z")
Hello,
I have a pipeline where I need to rename something around 1100 fields, the documents do not have all the fields, but in total I need to rename near 1100 fields.
Currently I have one `mutate` filter with a `rename` action for every field.
```auto
mutate {
rename => { "field1" => "newField1"}
rename => { "field2" => "newField2"}
...
rename => { "fieldN" => "newFieldN"}
}
```
Would using one `mutate` filter and one `rename` action with the fields make any difference? Or in the end it will be the same thing?
```auto
mutate {
rename {
"field1" => "newField1"
"field2" => "newField2"
"fieldN" => "newFieldN"
}
}
```
Anyone has a similar use case?
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [October 19, 2020, 9:05pm UTC](https://discuss.elastic.co/t/mutate-rename-multiple-fields-how-to-improve-performance/252606/2 "2020-10-19T21:05:02Z")
> [@leandrojmp](#):
>
> Or in the end it will be the same thing?
If there are multiple instances of an option on a filter they are merged when the configuration is parsed, so the two would be equivalent.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 16, 2020, 9:05pm UTC](https://discuss.elastic.co/t/mutate-rename-multiple-fields-how-to-improve-performance/252606/3 "2020-11-16T21:05:04Z")
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