# Why some field has '@' while others not?

**URL:** <https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038>\
**Category:** Elasticsearch\
**Created:** [June 29, 2018, 9:01pm UTC](https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038 "2018-06-29T21:01:45Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![ykang](https://avatars.discourse-cdn.com/v4/letter/y/f14d63/32.png) [@ykang](https://discuss.elastic.co/u/ykang)\
**Post date:** [June 29, 2018, 9:01pm UTC](https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038/1 "2018-06-29T21:01:45Z")

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in the this shttps://www.elastic.co/blog/how-to-centralize-logs-with-rsyslog-logstash-and-elasticsearch-on-ubuntu-14-04ample , the elastic doc stored as following:  
{  
"@timestamp" : "2015-11-18T18:45:00Z",  
"@version" : "1",  
"message" : "Your syslog message here",  
"sysloghost" : "[hostname.example.com](http://hostname.example.com)",  
"severity" : "info",  
"facility" : "daemon",  
"programname" : "my\_program",  
"procid" : "1234"  
}  
why some field, like and has a '@' sign prepend while others not ?  
what is the logic behind it?  
appreciate any help!

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**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 29, 2018, 9:34pm UTC](https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038/2 "2018-06-29T21:34:40Z")

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I think it started in Logstash as a convention for meta fields.

There is no specific behavior in elasticsearch regarding those names.

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<div class="post-metadata">

**Author:** ![ykang](https://avatars.discourse-cdn.com/v4/letter/y/f14d63/32.png) [@ykang](https://discuss.elastic.co/u/ykang)\
**Post date:** [June 29, 2018, 10:01pm UTC](https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038/3 "2018-06-29T22:01:00Z")

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appreciate the insight! Thank you.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 27, 2018, 10:01pm UTC](https://discuss.elastic.co/t/why-some-field-has-while-others-not/138038/4 "2018-07-27T22:01:04Z")

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Closed on July 27, 2018, 10:01pm UTC

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