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# Quick Start

This short guide will walk you through the basic process of using IoTDB. For a more-complete guide, please visit our website's [User Guide](../IoTDB-Introduction/What-is-IoTDB.md).

## Prerequisites

To use IoTDB, you need to have:

1. Java >= 1.8 (Please make sure the environment path has been set)
2. Set the max open files num as 65535 to avoid "too many open files" problem.

## Installation

IoTDB provides you three installation methods, you can refer to the following suggestions, choose one of them:

* Installation from source code. If you need to modify the code yourself, you can use this method.
* Installation from binary files. Download the binary files from the official website. This is the recommended method, in which you will get a binary released package which is out-of-the-box.(Coming Soon...)
* Using Docker：The path to the dockerfile is [github](https://github.com/apache/iotdb/blob/master/docker/src/main)


## Download

You can download the binary file from:
[Download Page](https://iotdb.apache.org/Download/)

## Configurations

configuration files are under "conf" folder

  * environment config module (`iotdb-env.bat`, `iotdb-env.sh`), 
  * system config module (`iotdb-engine.properties`)
  * log config module (`logback.xml`). 

For more, see [Config](../Reference/Config-Manual.md) in detail.

## Start

You can go through the following step to test the installation, if there is no error after execution, the installation is completed. 

### Start IoTDB

Users can start IoTDB by the start-server script under the sbin folder.

```
# Unix/OS X
> nohup sbin/start-server.sh -b
```
or 
```shell
> nohup sbin/start-server.sh >/dev/null 2>&1 &
```

parameters:
- by default, iotdb will run in the background
- "-v": show iotdb version
- "-f": run iotdb on the foreground and print logs on the console (by default before v0.14)
- "-b": run iotdb in the background which does not print logs on the console
- "-p \<pidfile\>": save the pid into target pidfile
- "-h": help
- "printgc"(must be at the end of the command): print the GC log (deprecated from v0.14 on)
- "-g": print the GC log
- "-c \<config folder\>": set IOTDB_CONF parameter
- "-D <a=b>": set system variables to IoTDB program.
- "-H \<filePath\> save heap dump file to \<filePath\> (only works when iotdb memory <16GB)"
- "-E <\filePath\> save error file of JVM to \<filePath\>"
- "-X \<command\> equal to -XX:\<command\>"

```
# Windows
> sbin\start-server.bat -c <conf_path>
```

Notice that Windows OS only support -v, -c, -f and -b.

if you want to use JMX to connect IOTDB, you may need to add/modify 

```
-Dcom.sun.management.jmxremote.rmi.port=<PORT> -Djava.rmi.server.hostname=<IP> 
```
to $IOTDB_JMX_OPTS in iotdb-env.sh. or iotdb-env.bat


### Use Cli

IoTDB offers different ways to interact with server, here we introduce basic steps of using Cli tool to insert and query data.

After installing IoTDB, there is a default user 'root', its default password is also 'root'. Users can use this
default user to login Cli to use IoTDB. The startup script of Cli is the start-cli script in the folder sbin. When executing the script, user should assign
IP, PORT, USER_NAME and PASSWORD. The default parameters are "-h 127.0.0.1 -p 6667 -u root -pw -root".

Here is the command for starting the Cli:

```
# Unix/OS X
> sbin/start-cli.sh -h 127.0.0.1 -p 6667 -u root -pw root

# Windows
> sbin\start-cli.bat -h 127.0.0.1 -p 6667 -u root -pw root
```

The command line client is interactive so if everything is ready you should see the welcome logo and statements:

```
 _____       _________  ______   ______
|_   _|     |  _   _  ||_   _ `.|_   _ \
  | |   .--.|_/ | | \_|  | | `. \ | |_) |
  | | / .'`\ \  | |      | |  | | |  __'.
 _| |_| \__. | _| |_    _| |_.' /_| |__) |
|_____|'.__.' |_____|  |______.'|_______/  version x.x.x


IoTDB> login successfully
IoTDB>
```

### Basic commands for IoTDB

Now, let us introduce the way of creating timeseries, inserting data and querying data. 

The data in IoTDB is organized as timeseries, in each timeseries there are some data-time pairs, and every timeseries is owned by a storage group. Before defining a timeseries, we should define a storage group using SET STORAGE GROUP, and here is an example: 

``` 
IoTDB> SET STORAGE GROUP TO root.ln
```

We can also use SHOW STORAGE GROUP to check created storage group:

```
IoTDB> SHOW STORAGE GROUP
+-----------------------------------+
|                      Storage Group|
+-----------------------------------+
|                            root.ln|
+-----------------------------------+
storage group number = 1
```

After the storage group is set, we can use CREATE TIMESERIES to create new timeseries. When we create a timeseries, we should define its data type and the encoding scheme. We create two timeseries as follow:

```
IoTDB> CREATE TIMESERIES root.ln.wf01.wt01.status WITH DATATYPE=BOOLEAN, ENCODING=PLAIN
IoTDB> CREATE TIMESERIES root.ln.wf01.wt01.temperature WITH DATATYPE=FLOAT, ENCODING=RLE
```

To query the specific timeseries, use SHOW TIMESERIES \<Path\>. \<Path\> represents the path of the timeseries. Its default value is null, which means querying all the timeseries in the system(the same as using "SHOW TIMESERIES root"). Here are the examples:

1. Query all timeseries in the system:

```
IoTDB> SHOW TIMESERIES
+-------------------------------+---------------+--------+--------+
|                     Timeseries|  Storage Group|DataType|Encoding|
+-------------------------------+---------------+--------+--------+
|       root.ln.wf01.wt01.status|        root.ln| BOOLEAN|   PLAIN|
|  root.ln.wf01.wt01.temperature|        root.ln|   FLOAT|     RLE|
+-------------------------------+---------------+--------+--------+
Total timeseries number = 2
```

2. Query a specific timeseries(root.ln.wf01.wt01.status):

```
IoTDB> SHOW TIMESERIES root.ln.wf01.wt01.status
+------------------------------+--------------+--------+--------+
|                    Timeseries| Storage Group|DataType|Encoding|
+------------------------------+--------------+--------+--------+
|      root.ln.wf01.wt01.status|       root.ln| BOOLEAN|   PLAIN|
+------------------------------+--------------+--------+--------+
Total timeseries number = 1
```

Insert timeseries data is the basic operation of IoTDB, you can use ‘INSERT’ command to finish this. Before insert you should assign the timestamp and the suffix path name:

```
IoTDB> INSERT INTO root.ln.wf01.wt01(timestamp,status) values(100,true);
IoTDB> INSERT INTO root.ln.wf01.wt01(timestamp,status,temperature) values(200,false,20.71)
```

The data we’ve just inserted displays like this:

```
IoTDB> SELECT status FROM root.ln.wf01.wt01
+-----------------------+------------------------+
|                   Time|root.ln.wf01.wt01.status|
+-----------------------+------------------------+
|1970-01-01T08:00:00.100|                    true|
|1970-01-01T08:00:00.200|                   false|
+-----------------------+------------------------+
Total line number = 2
```

We can also query several timeseries data at once like this:

```
IoTDB> SELECT * FROM root.ln.wf01.wt01
+-----------------------+--------------------------+-----------------------------+
|                   Time|  root.ln.wf01.wt01.status|root.ln.wf01.wt01.temperature|
+-----------------------+--------------------------+-----------------------------+
|1970-01-01T08:00:00.100|                      true|                         null|
|1970-01-01T08:00:00.200|                     false|                        20.71|
+-----------------------+--------------------------+-----------------------------+
Total line number = 2
```

The commands to exit the Cli are:  

```
IoTDB> quit
or
IoTDB> exit
```

For more on what commands are supported by IoTDB SQL, see [SQL Reference](../Reference/SQL-Reference.md).

### Stop IoTDB

The server can be stopped with ctrl-C or the following script:

```
# Unix/OS X
> sbin/stop-server.sh

# Windows
> sbin\stop-server.bat
```

### Administration management

There is a default user in IoTDB after the initial installation: root, and the default password is root. This user is an administrator user, who cannot be deleted and has all the privileges. Neither can new privileges be granted to the root user nor can privileges owned by the root user be deleted.

You can alter the password of root using the following command：
```
ALTER USER <username> SET PASSWORD <password>;
Example: IoTDB > ALTER USER root SET PASSWORD 'newpwd';
```

More about administration management：[Administration Management](https://iotdb.apache.org/UserGuide/V0.13.x/Administration-Management/Administration.html)

## Basic configuration

The configuration files is in the `conf` folder, includes:

* environment configuration (`iotdb-env.bat`, `iotdb-env.sh`),
* system configuration (`iotdb-engine.properties`)
* log configuration (`logback.xml`).