This is archived documentation for InfluxData product versions that are no longer maintained. For newer documentation, see the latest InfluxData documentation.
With InfluxDB installed, you’re ready to start doing some awesome things.
In this section we’ll use the influx
command line interface (CLI), which is included in all
InfluxDB packages and is a lightweight and simple way to interact with the database.
The CLI communicates with InfluxDB directly by making requests to the InfluxDB HTTP API over port 8086
by default.
Note: The database can also be used by making raw HTTP requests. See Writing Data and Querying Data for examples with the
curl
application.
Creating a database
If you’ve installed InfluxDB locally, the influx
command should be available via the command line.
Executing influx
will start the CLI and automatically connect to the local InfluxDB instance
(assuming you have already started the server with service influxdb start
or by running influxd
directly).
The output should look like this:
$ influx
Connected to http://localhost:8086 version 0.13.x
InfluxDB shell 0.13.x
>
Note: The InfluxDB HTTP API runs on port
8086
by default. Therefore,influx
will connect to port8086
andlocalhost
by default. If you need to alter these defaults, runinflux --help
.
The command line is now ready to take input in the form of the Influx Query Language (a.k.a InfluxQL) statements.
To exit the InfluxQL shell, type exit
and hit return.
A fresh install of InfluxDB has no databases (apart from the system _internal
),
so creating one is our first task.
You can create a database with the CREATE DATABASE <db-name>
InfluxQL statement,
where <db-name>
is the name of the database you wish to create.
Names of databases can contain any unicode character as long as the string is double-quoted.
Names can also be left unquoted if they contain only ASCII letters,
digits, or underscores and do not begin with a digit.
Throughout this guide, we’ll use the database name mydb
:
> CREATE DATABASE mydb
>
Note: After hitting enter, a new prompt appears and nothing else is displayed. In the CLI, this means the statement was executed and there were no errors to display. There will always be an error displayed if something went wrong. No news is good news!
Now that the mydb
database is created, we’ll use the SHOW DATABASES
statement
to display all existing databases:
> SHOW DATABASES
name: databases
---------------
name
_internal
mydb
>
Note: The
_internal
database is created and used by InfluxDB to store internal runtime metrics. Check it out later to get an interesting look at how InfluxDB is performing under the hood.
Unlike SHOW DATABASES
, most InfluxQL statements must operate against a specific database.
You may explicitly name the database with each query,
but the CLI provides a convenience statement, USE <db-name>
,
which will automatically set the database for all future requests. For example:
> USE mydb
Using database mydb
>
Now future commands will only be run against the mydb
database.
Writing and exploring data
Now that we have a database, InfluxDB is ready to accept queries and writes.
First, a short primer on the datastore.
Data in InfluxDB is organized by “time series”,
which contain a measured value, like “cpu_load” or “temperature”.
Time series have zero to many points
, one for each discrete sample of the metric.
Points consist of time
(a timestamp), a measurement
(“cpu_load”, for example),
at least one key-value field
(the measured value itself, e.g.
“value=0.64”, or “temperature=21.2”), and zero to many key-value tags
containing any metadata about the value (e.g.
“host=server01”, “region=EMEA”, “dc=Frankfurt”).
Conceptually you can think of a measurement
as an SQL table,
where the primary index is always time.
tags
and fields
are effectively columns in the table.
tags
are indexed, and fields
are not.
The difference is that, with InfluxDB, you can have millions of measurements,
you don’t have to define schemas up-front, and null values aren’t stored.
Points are written to InfluxDB using the Line Protocol, which follows the following format:
<measurement>[,<tag-key>=<tag-value>...] <field-key>=<field-value>[,<field2-key>=<field2-value>...] [unix-nano-timestamp]
The following lines are all examples of points that can be written to InfluxDB:
cpu,host=serverA,region=us_west value=0.64
payment,device=mobile,product=Notepad,method=credit billed=33,licenses=3i 1434067467100293230
stock,symbol=AAPL bid=127.46,ask=127.48
temperature,machine=unit42,type=assembly external=25,internal=37 1434067467000000000
Note: More information on the line protocol can be found on the Write Syntax page.
To insert a single time-series datapoint into InfluxDB using the CLI, enter INSERT
followed by a point:
> INSERT cpu,host=serverA,region=us_west value=0.64
>
A point with the measurement name of cpu
and tag host
has now been written to the database, with the measured value
of 0.64
.
Now we will query for the data we just wrote:
> SELECT host, region, value FROM cpu
name: cpu
---------
time host region value
2015-10-21T19:28:07.580664347Z serverA us_west 0.64
>
Note: We did not supply a timestamp when writing our point. When no timestamp is supplied for a point, InfluxDB assigns the local current timestamp when the point is ingested. That means your timestamp will be different.
Let’s try storing another type of data, with two fields in the same measurement:
> INSERT temperature,machine=unit42,type=assembly external=25,internal=37
>
To return all fields and tags with a query, you can use the *
operator:
> SELECT * FROM temperature
name: temperature
-----------------
time external internal machine type
2015-10-21T19:28:08.385013942Z 25 37 unit42 assembly
>
InfluxQL has many features and keywords that are not covered here, including support for Go-style regex. For example:
> SELECT * FROM /.*/ LIMIT 1
--
> SELECT * FROM cpu_load_short
--
> SELECT * FROM cpu_load_short WHERE value > 0.9
This is all you need to know to write data into InfluxDB and query it back. To learn more about the InfluxDB write protocol, check out the guide on Writing Data. To further explore the query language, check out the guide on Querying Data. For more information on InfluxDB concepts, check out the Key Concepts page.