InfluxDB line protocol reference

InfluxDB line protocol is a text-based format for writing points to InfluxDB.

Line protocol syntax

<measurement>[,<tag_key>=<tag_value>[,<tag_key>=<tag_value>]] <field_key>=<field_value>[,<field_key>=<field_value>] [<timestamp>]

Line protocol accepts the newline character \n and is whitespace-sensitive.

Note Line protocol does not support the newline character \n in tag values or field values.

Syntax description

InfluxDB line protocol informs InfluxDB of the data’s measurement, tag set, field set, and timestamp.

Performance tips:

• Before sending data to InfluxDB, sort by tag key to match the results from the Go bytes.Compare function.
• To significantly improve compression, use the coarsest precision possible for timestamps.
• Use the Network Time Protocol (NTP) to synchronize time between hosts. InfluxDB uses a host’s local time in UTC to assign timestamps to data. If a host’s clock isn’t synchronized with NTP, the data that the host writes to InfluxDB may have inaccurate timestamps.

Data types

Boolean syntax for writes and queries

Acceptable Boolean syntax differs for data writes and data queries. For more information, see Frequently asked questions.

Field type discrepancies

In a measurement, a field’s type cannot differ in a shard, but can differ across shards.

To learn how field value type discrepancies can affect SELECT * queries, see How does InfluxDB handle field type discrepancies across shards?.

Examples

Write the field value -1.234456e+78 as a float to InfluxDB

> INSERT mymeas value=-1.234456e+78

InfluxDB supports field values specified in scientific notation.

Write a field value 1.0 as a float to InfluxDB

> INSERT mymeas value=1.0

Write the field value 1 as a float to InfluxDB

> INSERT mymeas value=1

Write the field value 1 as an integer to InfluxDB

> INSERT mymeas value=1i

Write the field value stringing along as a string to InfluxDB

> INSERT mymeas value="stringing along"

Always double quote string field values. More on quoting below.

Write the field value true as a Boolean to InfluxDB

> INSERT mymeas value=true

Do not quote Boolean field values. The following statement writes true as a string field value to InfluxDB:

> INSERT mymeas value="true"

Attempt to write a string to a field that previously accepted floats

If the timestamps on the float and string are stored in the same shard:

> INSERT mymeas value=3 1465934559000000000
> INSERT mymeas value="stringing along" 1465934559000000001
ERR: {"error":"field type conflict: input field \"value\" on measurement \"mymeas\" is type string, already exists as type float"}

If the timestamps on the float and string are not stored in the same shard:

> INSERT mymeas value=3 1465934559000000000
> INSERT mymeas value="stringing along" 1466625759000000000
>

Quoting, special characters, and additional naming guidelines

Quoting

* InfluxDB line protocol allows users to double and single quote measurement names, tag keys, tag values, and field keys. It will, however, assume that the double or single quotes are part of the name, key, or value. This can complicate query syntax (see the example below).

Examples

Invalid line protocol - Double quote the timestamp

> INSERT mymeas value=9 "1466625759000000000"
ERR: {"error":"unable to parse 'mymeas value=9 \"1466625759000000000\"': bad timestamp"}

Double quoting (or single quoting) the timestamp yields a bad timestamp error.

Semantic error - Double quote a Boolean field value

> INSERT mymeas value="true"
> SHOW FIELD KEYS FROM "mymeas"
name: mymeas
------------
fieldKey     fieldType
value           string

InfluxDB assumes that all double quoted field values are strings.

Semantic error - Double quote a measurement name

> INSERT "mymeas" value=200
> SHOW MEASUREMENTS
name: measurements
------------------
name
"mymeas"
> SELECT * FROM mymeas
> SELECT * FROM "mymeas"
> SELECT * FROM "\"mymeas\""
name: "mymeas"
--------------
time                                        value
2016-06-14T20:36:21.836131014Z     200

If you double quote a measurement in line protocol, any queries on that measurement require both double quotes and escaped (\) double quotes in the FROM clause.

Special characters

You must use a backslash character \ to escape the following special characters:

• In string field values, you must escape:

  • double quotes

  • backslash character

For example, \" escapes double quote.

Note on backslashes:

• If you use multiple backslashes, they must be escaped. Influx interprets backslashes as follows:
  • \ or \\ interpreted as \
  • \\\ or \\\\ interpreted as \\
  • \\\\\ or \\\\\\ interpreted as \\\, and so on

• In tag keys, tag values, and field keys, you must escape:
  • commas
  • equal signs
  • spaces

For example, \, escapes a comma.

• In measurements, you must escape:

  • commas

  • spaces

You do not need to escape other special characters.

Examples

Write a point with special characters

> INSERT "measurement\ with\ quo⚡️es\ and\ emoji",tag\ key\ with\ sp🚀ces=tag\,value\,with"commas" field_k\ey="string field value, only \" need be esc🍭ped"

The system writes a point where the measurement is "measurement with quo⚡️es and emoji", the tag key is tag key with sp🚀ces, the tag value is tag,value,with"commas", the field key is field_k\ey and the field value is string field value, only " need be esc🍭ped.

Additional naming guidelines

# at the beginning of the line is a valid comment character for line protocol. InfluxDB will ignore all subsequent characters until the next newline \n.

Measurement names, tag keys, tag values, field keys, and field values are case sensitive.

InfluxDB line protocol accepts InfluxQL keywords as identifier names. In general, we recommend avoiding using InfluxQL keywords in your schema as it can cause confusion when querying the data.

Note: Avoid using the reserved keys _field and _measurement. If these keys are included as a tag or field key, the associated point is discarded.

The keyword time is a special case. time can be a continuous query name, database name, measurement name, retention policy name, subscription name, and user name. In those cases, time does not require double quotes in queries. time cannot be a field key or tag key; InfluxDB rejects writes with time as a field key or tag key and returns an error. See Frequently Asked Questions for more information.

InfluxDB line protocol in practice

To learn how to write line protocol to the database, see Tools.

Duplicate points

A point is uniquely identified by the measurement name, tag set, field set, and timestamp

If you write a point to a series with a timestamp that matches an existing point, the field set becomes a union of the old and new field set, and conflicts favor the new field set.

For a complete example of this behavior and how to avoid it, see How does InfluxDB handle duplicate points?

Duplicate keys

If you have a tag key and field key with the same name in a measurement, one of the keys will return appended with a _1 in query results (and as a column header in Chronograf). For example, location and location_1. To query a duplicate key, drop the _1 and use the InfluxQL ::tag or ::field syntax in your query, for example:

  SELECT "location"::tag, "location"::field FROM "database_name"."retention_policy"."measurement"