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# IoTDB Working Process

## Main link

IoTDB official website：https://iotdb.apache.org/

Code library：https://github.com/apache/iotdb

Code library for go language: https://github.com/apache/iotdb-client-go

Library for resources (project's documents, compiler, etc): https://github.com/apache/iotdb-bin-resources

Get started quickly：http://iotdb.apache.org/UserGuide/Master/QuickStart/QuickStart.html

Jira Task Management：https://issues.apache.org/jira/projects/IOTDB/issues

Wiki Document Management：https://cwiki.apache.org/confluence/display/IOTDB/Home\

Mailing list: https://lists.apache.org/list.html?dev@iotdb.apache.org

Everyday build: https://ci-builds.apache.org/job/IoTDB/job/IoTDB-Pipe/job/master/

Slack: https://apacheiotdb.slack.com/join/shared_invite/zt-qvso1nj8-7715TpySZtZqmyG5qXQwpg#/shared-invite/email

## Subscribe to mailing list

The mailing list is where the Apache project conducts technical discussions and communication with users. Follow the mailing list to receive mail.

Mailing list address：dev@iotdb.apache.org

Follow method: Send an email to dev-subscribe@iotdb.apache.org with the email you want to receive the email, the subject content is not limited, after receiving the reply, send a confirmation email to the confirmation address again (the confirmation address is longer, it is recommended  gmail mailbox).


Other mailing list:
* notifications@iotdb.apache.org (for JIRA information notification.)
  * If you only want to receive individual Jira notifications that you are interest in, you do not need to subscribe this mailing list. Instead, you just need to click "start-watching this issue" on the jira issue webpage or just comment on this issue.
* commits@iotdb.apache.org (Any code changes will be notified here, please note that this mailing list will be very large)
* reviews@iotdb.apache.org (Any code review comments will be notified here, please note that this mailing list will be very large)


## New features, bug feedback, improvements and more

All features or bugs that you want IoTDB to do can be raised on Jira：https://issues.apache.org/jira/projects/IOTDB/issues

You can choose issue types: bug, improvement, new feature, etc.  New issues will be automatically synchronized to the mailing list (notifications@), and subsequent discussions can be left on jira or on the mailing list. When the issue is resolved, close the issue.

## Email discussion content (English)

* Joining the mailing list for the first time can introduce youself briefly.  (Hi, I'm xxx ...)

* Before developing a new feature, you can send an e-mail to declare the task you want to do.（Hi，I'm working on issue IOTDB-XXX，My plan is ...）

## Contributing documents

The content of all IoTDB official websites is in the docs of the project root directory:

* docs/SystemDesign: System Design Document-English Version
* docs/zh/SystemDesign: System Design Document-Chinese Version
* docs/UserGuide: User Guide English Version
* docs/zh/UserGuide: User Guide Chinese Version
* docs/Community: community English Version
* docs/zh/Community: community Chinese Version
* docs/Development: Development Guide English Version
* docs/zh/Development: Development Guide Chinese Version

Correspondence between versions and branches on the official website:

* In progress -> master
* major_version.x -> rel/major_version （eg 0.9.x -> rel/0.9）

Precautions:

* Images in Markdown can be uploaded to https://github.com/apache/iotdb-bin-resources for url
* Do not use special Unicode chars, e.g., U+FF1A 
* Do not use the character of dollar (as we will use Latex to generate pdf files)

## Code Formatting

We use the [Spotless
plugin](https://github.com/diffplug/spotless/tree/main/plugin-maven) together with [google-java-format](https://github.com/google/google-java-format) to format our Java code. You can configure your IDE to automatically apply formatting on saving with these steps(Take idea as an example):

1. Download the [google-java-format
   plugin v1.7.0.5](https://plugins.jetbrains.com/plugin/8527-google-java-format/versions/stable/83169), it can be installed in IDEA (Preferences -> plugins -> search google-java-format), [More detailed setup manual](https://github.com/google/google-java-format#intellij-android-studio-and-other-jetbrains-ides)
2. Install the plugin from disk (Plugins -> little gear icon -> "Install plugin from disk" -> Navigate to downloaded zip file)
3. In the plugin settings, enable the plugin and keep the default Google code style (2-space indents)
4. Remember to never update this plugin to a later version，until Spotless was upgraded to version 1.8+.
5. Install the [Save Actions
   plugin](https://plugins.jetbrains.com/plugin/7642-save-actions) , and enable the plugin, along with "Optimize imports" and "Reformat file"
6. In the "Save Actions" settings page, setup a "File Path Inclusion" for `.*\.java`. Otherwise you will get unintended reformatting in other files you edit.
7. Fix the issues of reordering the import packages: in IDEA: choose: Preferences | Editor | Code Style | Java | imports. At the tail of the panel, there is "Import Layout", change it to:
```shell
   import org.apache.iotdb.*
   <blank line>
   import all other imports
   <blank line>
   import java.*
   <blank line>
   import static all other imports
```


## Contributing code

You can go to jira to pick up the existing issue or create your own issue and get it. The comment says that I can do this issue.

* Clone the repository to your own local repository, clone to the local, and associate the apache repository as the upstream upstream repository.
* Cut out a new branch from master. The branch name is determined by the function of this branch. It is usually called f_new_feature (such as f_storage_engine) or fix_bug (such as fix_query_cache_bug).
* Add code style as the root java-google-style.xml in the idea
* Modify the code and add test cases (unit test, integration test)
  * Integration test reference:server/src/test/java/org/apache/iotdb/db/integration/IoTDBTimeZoneIT
* Use `mvn spotless:check` to check the code style and use `mvn spotless:apply` to correct the code style
* Submit a PR, starting with [IOTDB-jira number]
* Email to dev mailing list：(I've submitted a PR for issue IOTDB-xxx [link])
* Make changes based on other people's reviews and continue to update until merged
* close jira issue

# IoTDB Debug Guide

## Import the code

### Intellij idea

It is recommended to use Intellij idea。```mvn clean package -DskipTests``` 

Mark ```antlr/target/generated-sources/antlr4``` and```thrift/target/generated-sources/thrift``` as ```Source Root```。 

### Eclipse

If it is a version before eclipse 2019，users need to be executed in the root directory of IoTDB `mvn eclipse:eclipse -DskipTests`。

import -> General -> Existing Projects into Workspace -> Select IoTDB root directory

If the version after eclipse 2019

import -> Maven -> Existing Maven Projects

## Debugging code


* Server main function：`server/src/main/java/org/apache/iotdb/db/service/IoTDB`, can be started in debug mode.
* Cli：`cli/src/main/java/org/apache/iotdb/cli/`，Use Cli for linux and WinCli for windows, you can start directly with the parameter "`-h 127.0.0.1 -p 6667 -u root -pw root`"
* Server rpc implementation (mainly used for cli and server communication, generally start interruption point here):`server/src/main/java/org/apache/iotdb/db/service/TSServiceImpl`
* all jdbc statements：`executeStatement(TSExecuteStatementReq req)`
* jdbc query：`executeQueryStatement(TSExecuteStatementReq req)`	
* native Write interface：`insertRecord(TSInsertRecordReq req)`
`insertTablet(TSInsertTabletReq req)`

* Storage engine`org.apache.iotdb.db.engine.StorageEngine`
* Query engine `org.apache.iotdb.db.qp.QueryProcessor`


# Frequent Questions When Compiling the Source Code

I could not download thrift-* tools, like `Could not get content
org.apache.maven.wagon.TransferFailedException: Transfer failed for https://github.com/apache/iotdb-bin-resources/blob/main/compile-tools/thrift-0.14-ubuntu`

 It is due to some network problems (especially in China), you can:

 * Download the file from the URL manually;
      * https://github.com/apache/iotdb-bin-resources/blob/main/compile-tools/thrift-0.14-ubuntu

      * https://github.com/apache/iotdb-bin-resources/blob/main/compile-tools/thrift-0.14-MacOS

 * Put the file to thrift/target/tools/

 * Re-run maven command like `mvn compile`


## Recommended Debug Tool 

The initial committer of IoTDB is using this  [Java profiler](https://www.ej-technologies.com/products/jprofiler/overview.html) to debug. Welcome all IoTDB contributors to use it.