With InfluxDB open source (OSS) 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 API over port
8086 by default.
Creating a database
If you’ve installed InfluxDB locally, the
influx command should be available via the command line.
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
The output should look like this:
$ influx -precision rfc3339 Connected to http://localhost:8086 version 1.8.x InfluxDB shell 1.8.x >
- The InfluxDB API runs on port
8086by default. Therefore,
influxwill connect to port
localhostby default. If you need to alter these defaults, run
-precisionargument specifies the format/precision of any returned timestamps. In the example above,
rfc3339tells InfluxDB to return timestamps in RFC3339 format (
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
so creating one is our first task.
You can create a database with the
CREATE DATABASE <db-name> InfluxQL statement,
<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
> 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 >
_internaldatabase 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.
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,
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
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.
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 InfluxDB 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: For details on the InfluxDB line protocol, see InfluxDB line protocol syntax page.
To insert a single time series data point 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 tags
region has now been written to the database, with the measured
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
> SELECT * FROM "temperature" name: temperature ----------------- time external internal machine type 2015-10-21T19:28:08.385013942Z 25 37 unit42 assembly >
LIMITclause on a large database can cause performance issues. You can use
Ctrl+Cto cancel a query that is taking too long to respond.
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.