ClickHouse

ClickHouse (clickhouse)

Write events to a ClickHouse table using the HTTP interface or native endpoint.

Database Enterprise edition json

Minimal example

output:
  clickhouse:
    endpoint: ~
    table: ~

JSON

{
  "output": {
    "clickhouse": {
      "endpoint": null,
      "table": null
    }
  }
}

Contents

• Minimal example

• Fields

• Authentication

• Connection

• Payload

• Schema

• Schema

A ✓ marks a field that accepts a context variable such as {{ VARIABLE }}.

Fields

Field	Type	Required	Description
retry	Retry		How to retry failed inserts.
batch	Batch		Batch events before inserting.

Authentication

Authentication

Field	Type	Required	Description
auth	Auth		Optional authentication settings (basic auth, token, or TLS material).

Connection

Connection

Field	Type	Required	Description
endpoint	string	✅	Base endpoint (example: https://localhost:8443 or http://cluster-router:8123).
database	string		Optional database override; defaults to server-side default database.
table	string	✅	Target table for writes.
compression	Compression		Optional compression codec negotiated with the server. Allowed values: none, lz4
settings	map (string)		Additional ClickHouse setting key/value pairs (forwarded as query params).
insecure-skip-verify ✓	boolean (bool)		Skip TLS certificate verification (development only). Default: false
timezone	string		Optional timezone override used when formatting temporal data.

Payload

Payload

Field	Type	Required	Description
input-field	field (string)		Optional event field to treat as the raw payload. When omitted the entire event is used. Examples: data_field
format	Format		Insert format to use when sending data to ClickHouse. Allowed values: json-each-row, json-compact-each-row, csv, values

Schema

Schema

Field	Type	Required	Description
columns	Columns[]		Declarative column mapping; leave empty to stream JSONEachRow documents.

Schema

• Retry - Backoff Fields
• Retry Fields
• Batch Fields
• Auth Fields
• Columns Fields
• Settings Table
• Retry - Backoff - Strategy Options
• Batch - Mode Options
• Compression Options
• Format Options

Retry - Backoff Fields

Field	Type	Required	Description
strategy	Strategy		Backoff strategy to use (default exponential). Allowed values: exponential, linear, fixed
base	string		Base delay before retrying (e.g. “200ms”).
max	string		Maximum delay between retries.
jitter ✓	boolean (bool)		Whether to add jitter to retry delays. Default: false

Retry Fields

Field	Type	Required	Description
max-attempts	number (integer)		Maximum attempts before giving up. Examples: 42, 1.2e-10
forever ✓	boolean (bool)		Retry indefinitely until cancelled. Default: false
backoff	Backoff		Backoff strategy configuration.

Batch Fields

Field	Type	Required	Description
fixed-size ✓	number (integer)		maximum number of events in an output batch. Examples: 42, 1.2e-10
max-bytes ✓	number (integer)		Close the batch before adding an event that would make the serialized request payload exceed this many bytes. Examples: 42, 1.2e-10
mode	Mode	✅	If ‘document’ send on end of document generated by input. If ‘fixed’, use fixed_size. Allowed values: fixed, document
timeout	time-interval (string)	✅	interval after which the batch is sent, to keep throughput going (default 100ms). Default: 100ms Examples: 500ms, 2h
header	multiline-text (string)		put a header line before the batch.
footer	multiline-text (string)		put a header line after the last line of the batch.
use-document-marker ✓	boolean (bool)		Enrich the job metadata with a document marker (for document handling in batch mode). Default: false
wrap-as-json ✓	boolean (bool)		Format the output batch as a JSON array. Default: false

Auth Fields

Field	Type	Required	Description
username	string
password	string
access-token	string
tls-certificate	string
tls-key	string

Columns Fields

Field	Type	Required	Description
name	string	✅
field	string		Event field name (dot-notation) to pull data from.
pointer	json-pointer (string)		JSON Pointer to extract from the event (used when field is insufficient).
expression	string		Optional ClickHouse expression to compute the column.
r-type	string		Explicit ClickHouse type (e.g. DateTime64(3), Nullable(String)).
default	string		Default value used when the source field/pointer resolves to null.
codec	string		Optional codec hint (e.g. LZ4, ZSTD).

Settings Table

Setting	Value
setting.name	value

Value format: templated-text.

Retry - Backoff - Strategy Options

Value	Aliases	Name	Description
exponential		exponential
linear		linear
fixed		fixed

Batch - Mode Options

Value	Aliases	Name	Description
fixed		fixed
document		document

Compression Options

Value	Aliases	Name	Description
none		none
lz4		lz4

Format Options

Value	Aliases	Name	Description
json-each-row		json-each-row
json-compact-each-row		json-compact-each-row
csv		csv
values		values