# +FORMAT syntax works for @timestamp field only?
**URL:** https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037
**Category:** Logstash
**Created:** [October 24, 2019, 9:53am UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037 "2019-10-24T09:53:55Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jetnet](https://discuss.elastic.co/u/jetnet)
#### Post date: [October 24, 2019, 9:53am UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037/1 "2019-10-24T09:53:55Z")
can some other timestamp field be used with `+FORMAT` syntax?
```auto
index => "${ELASTICSEARCH_INDEX}.%{+yyyy.MM.dd}"
```
the above config line would use `@timestamp` as the input for the format definition, but I'd like to use some other field.
Thanks!
---
### Author:  [@jetnet](https://discuss.elastic.co/u/jetnet)
#### Post date: [October 24, 2019, 12:54pm UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037/2 "2019-10-24T12:54:59Z")
since I don't need the default `@timestamp` field in the index, but would like to use the `+FORMAT` syntax for the index naming, I have to use the following workaround (my "local" timestamp field is `server_time` in ISO8601 format):
```auto
mutate {
copy => { "server_time" => "@timestamp" }
add_field => { "[@metadata][date]" => "%{+yyyy.MM.dd}" }
remove_field => ["@version", "@timestamp", "host", ...]
}
```
and in the ES output:
```auto
index => "${ELASTICSEARCH_INDEX}-%{[@metadata][date]}"
```
would be glad if someone could share a more elegant solution.
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [October 24, 2019, 1:00pm UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037/3 "2019-10-24T13:00:26Z")
> [@jetnet](#):
>
> can some other timestamp field be used with `+FORMAT` syntax?
No, it always uses @timestamp.
---
### Author:  [@jetnet](https://discuss.elastic.co/u/jetnet)
#### Post date: [October 24, 2019, 2:06pm UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037/4 "2019-10-24T14:06:17Z")
thanks for confirming that!
I'm asking myself: why didn't they mention this point in the [documentation](https://www.elastic.co/guide/en/logstash/current/event-dependent-configuration.html#sprintf)? Just one small sentence would save a lot of time...
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [November 21, 2019, 2:06pm UTC](https://discuss.elastic.co/t/format-syntax-works-for-timestamp-field-only/205037/5 "2019-11-21T14:06:17Z")
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