# The sync principle of logstash-input-jdbc?

**URL:** <https://discuss.elastic.co/t/the-sync-principle-of-logstash-input-jdbc/54017>\
**Category:** Logstash\
**Created:** [June 27, 2016, 9:25am UTC](https://discuss.elastic.co/t/the-sync-principle-of-logstash-input-jdbc/54017 "2016-06-27T09:25:10Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![laoyang360](https://avatars.discourse-cdn.com/v4/letter/l/a9a28c/32.png) [@laoyang360](https://discuss.elastic.co/u/laoyang360)\
**Post date:** [June 27, 2016, 9:25am UTC](https://discuss.elastic.co/t/the-sync-principle-of-logstash-input-jdbc/54017/1 "2016-06-27T09:25:10Z")

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I want to know the sync principle of logstash-input-jdbc?  
I know it is based on the time compare method like :

```
  select
   *
   from
   cc
  where cc.modified_at > :sql_last_value,

```

Does it also based on database trigger methon.  
When I grep the logstash-input-jdbc source, I find there is no any trigger information.

If you know, please help me.  
Any help would be sincerely appreciate.

---

<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [June 29, 2016, 12:44am UTC](https://discuss.elastic.co/t/the-sync-principle-of-logstash-input-jdbc/54017/2 "2016-06-29T00:44:07Z")

</div>

It doesn't know anything about triggers.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 4:50am UTC](https://discuss.elastic.co/t/the-sync-principle-of-logstash-input-jdbc/54017/3 "2017-07-06T04:50:36Z")

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Closed on July 6, 2017, 4:50am UTC