# Using LIMIT on JDBC input as opposed to jdbc\_page\_size

**URL:** <https://discuss.elastic.co/t/using-limit-on-jdbc-input-as-opposed-to-jdbc-page-size/109970>\
**Category:** Logstash\
**Created:** [December 1, 2017, 5:50pm UTC](https://discuss.elastic.co/t/using-limit-on-jdbc-input-as-opposed-to-jdbc-page-size/109970 "2017-12-01T17:50:50Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![arisbanach](https://avatars.discourse-cdn.com/v4/letter/a/f07891/32.png) [@arisbanach](https://discuss.elastic.co/u/arisbanach)\
**Post date:** [December 1, 2017, 5:50pm UTC](https://discuss.elastic.co/t/using-limit-on-jdbc-input-as-opposed-to-jdbc-page-size/109970/1 "2017-12-01T17:50:51Z")

</div>

I am trying to import a large database from a remote server using the JDBC input plugin and have been having some issues. After testing some various configs, I am seeing that if I set LIMIT 10 in the `statement` itself, I will get the results back very fast. However, I see there is a parameter called `jdbc_page_size` that takes care of limits and offsets so that a statement like `SELECT *` can be broken up and you can get your results one chunk at a time (at least that's how I understand it?). When I remove the LIMIT part of the statement and set `jdbc_page_size => 10` to test it out, Logstash outputs:

```
Dec 01 17:36:59 elastisearch systemd[1]: Started logstash.
Dec 01 17:37:07 elastisearch logstash[24787]: Sending Logstash's logs to /var/log/logstash which is now configured via log4j2.properties

```

and then hangs. I have yet to see it actually output anything at all.

Here is my config. Am I doing something wrong?

Thank you

```
input {
  jdbc {
    jdbc_driver_library => "/home/ubuntu/postgresql-42.1.4.jar"
    jdbc_driver_class => "org.postgresql.Driver"
    jdbc_connection_string => "jdbc:postgresql://hostname.com:5432/dbname?user=\
myusername&password=mypassword"
    jdbc_user => "myusername"
    jdbc_password => "mypassword"
    statement => "SELECT * from tablename"
    jdbc_paging_enabled => "true"
    jdbc_page_size => "100"
    #jdbc_fetch_size => "5"                                                                                                  
  }
}
output {
  stdout {
    codec => rubydebug
  }
  elasticsearch {
    hosts => ["localhost"]
    index => "db-name"
  }
}

```

It finally started. Just took an extra long time. Can someone explain why doing a LIMIT in the statement returns it super fast? Just curious what it's actually doing differently under the hood.

---

<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:** [December 29, 2017, 5:50pm UTC](https://discuss.elastic.co/t/using-limit-on-jdbc-input-as-opposed-to-jdbc-page-size/109970/2 "2017-12-29T17:50:55Z")

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