# SinceDB null, question

**URL:** <https://discuss.elastic.co/t/sincedb-null-question/223169>\
**Category:** Logstash\
**Created:** [March 11, 2020, 3:09pm UTC](https://discuss.elastic.co/t/sincedb-null-question/223169 "2020-03-11T15:09:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Incauto](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/incauto/32/60149_2.png) [@Incauto](https://discuss.elastic.co/u/Incauto)\
**Post date:** [March 11, 2020, 3:09pm UTC](https://discuss.elastic.co/t/sincedb-null-question/223169/1 "2020-03-11T15:09:15Z")

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If I set sincedb\_path = /dev/null in a logstash configuration, that means that every time I run logstash, de data will be re-indexed in elastic?  
this will create duplicates?  
what problems could arise with this?

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**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [March 11, 2020, 3:25pm UTC](https://discuss.elastic.co/t/sincedb-null-question/223169/2 "2020-03-11T15:25:01Z")

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If sincedb\_path is set to /dev/null then the in-memory sincedb is not persisted across restarts. So every time logstash restarts it will re-read the files. Unless you are setting the document\_id based on the content of the event that will result in duplicates. This results in it re-doing work, which is wasteful, and it results in duplicate records in elasticsearch. Whether either of these is a problem is really up to you.

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**Author:** ![Incauto](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/incauto/32/60149_2.png) [@Incauto](https://discuss.elastic.co/u/Incauto)\
**Post date:** [March 11, 2020, 3:39pm UTC](https://discuss.elastic.co/t/sincedb-null-question/223169/3 "2020-03-11T15:39:04Z")

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I was seeing the confs of a fellow worker, and find out that in his configurations he has setted sincedb to null, the system has been restarted many times, so I guess that means that there is more than duplicate, and triplicates?

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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:** [April 8, 2020, 3:39pm UTC](https://discuss.elastic.co/t/sincedb-null-question/223169/4 "2020-04-08T15:39:08Z")

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