---
layout: page
title: Developing Calcite
---
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Want to help add a feature or fix a bug?

* TOC
{:toc}

## Source code

You can get the source code by
[downloading a release]({{ site.baseurl }}/downloads)
or from source control.

Calcite uses git for version control.  The canonical source is in
[Apache](https://git-wip-us.apache.org/repos/asf/calcite.git),
but most people find the
[Github mirror](https://github.com/apache/calcite) more
user-friendly.

## Download source, build, and run tests

Prerequisites are git, maven (3.5.2 or later)
and Java (JDK 7 or later, 9 preferred) on your path.

Create a local copy of the git repository, `cd` to its root directory,
then build using maven:

{% highlight bash %}
$ git clone git://github.com/apache/calcite.git
$ cd calcite
$ mvn install
{% endhighlight %}

The HOWTO describes how to
[build from a source distribution]({{ site.baseurl }}/docs/howto.html#building-from-a-source-distribution),
[run more or fewer tests]({{ site.baseurl }}/docs/howto.html#running-tests) and
[run integration tests]({{ site.baseurl }}/docs/howto.html#running-integration-tests).

## Contributing

We welcome contributions.

If you are planning to make a large contribution, talk to us first! It
helps to agree on the general approach. Log a
[JIRA case](https://issues.apache.org/jira/browse/CALCITE) for your
proposed feature or start a discussion on the dev list.

Fork the github repository, and create a branch for your feature.

Develop your feature and test cases, and make sure that
`mvn install` succeeds. (Run extra tests if your change warrants it.)

Commit your change to your branch, and use a comment that starts with
the JIRA case number, like this:

{% highlight text %}
[CALCITE-345] AssertionError in RexToLixTranslator comparing to date literal
{% endhighlight %}

If your change had multiple commits, use `git rebase -i master` to
squash them into a single commit, and to bring your code up to date
with the latest on the main line.

Then push your commit(s) to github, and create a pull request from
your branch to the calcite master branch. Update the JIRA case
to reference your pull request, and a committer will review your
changes.

## Continuous Integration Testing

Calcite has a collection of Jenkins jobs on ASF-hosted infrastructure.
They are all organized in a single view and available at
[https://builds.apache.org/view/A-D/view/Calcite/](https://builds.apache.org/view/A-D/view/Calcite/).

## Getting started

Calcite is a community, so the first step to joining the project is to introduce yourself.
Join the [developers list](http://mail-archives.apache.org/mod_mbox/calcite-dev/)
and send an email.

If you have the chance to attend a [meetup](http://www.meetup.com/Apache-Calcite/),
or meet [members of the community](http://calcite.apache.org/develop/#project-members)
at a conference, that's also great.

Choose an initial task to work on. It should be something really simple,
such as a bug fix or a [Jira task that we have labeled
"newbie"](https://issues.apache.org/jira/issues/?jql=labels%20%3D%20newbie%20%26%20project%20%3D%20Calcite%20%26%20status%20%3D%20Open).
Follow the [contributing guidelines](#contributing) to get your change committed.

After you have made several useful contributions we may
[invite you to become a committer](https://community.apache.org/contributors/).
We value all contributions that help to build a vibrant community, not just code.
You can contribute by testing the code, helping verify a release,
writing documentation or the web site,
or just by answering questions on the list.

