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Official

ClickHouse

This destination plugin lets you sync data from a CloudQuery source to ClickHouse database

Make sure to sign up and run cloudquery login before running your first sync.

Publisher

cloudquery

Repositorygithub.com

Latest version

v4.0.6

Type

Destination

Platforms

Date Published

April 30, 2024

Price

Free

Documentation Changelog

Overview Types

Overview

ClickHouse destination plugin

This destination plugin lets you sync data from a CloudQuery source to ClickHouse database.

It supports append write mode only. Write mode selection is required through write_mode.

Supported database versions: >= 22.1.2

Configuration

Example

kind: destination
spec:
  name: "clickhouse"
  path: "cloudquery/clickhouse"
  registry: "cloudquery"
  version: "v4.0.6"
  write_mode: "append"
  spec:
    connection_string: "clickhouse://${CH_USER}:${CH_PASSWORD}@localhost:9000/${CH_DATABASE}"
    # Optional parameters
    # cluster: ""
    # ca_cert: ""
    # engine:
    #   name: MergeTree
    #   parameters: []
    #
    # batch_size: 10000
    # batch_size_bytes: 5242880 # 5 MiB
    # batch_timeout: 20s

This example configures a ClickHouse instance, located at localhost:9000. It expects CH_USER, CH_PASSWORD and CH_DATABASE environment variables to be set. The (top level) spec section is described in the Destination Spec Reference.

Make sure you use environment variable expansion in production instead of committing the credentials to the configuration file directly.

ClickHouse spec

This is the (nested) spec used by the ClickHouse destination plugin.

connection_string (string) (required)
Connection string to connect to the database. See SDK documentation for more details.
cluster (string) (optional) (default: not used)
Cluster name to be used for distributed DDL. If the value is empty, DDL operations will affect only the server the plugin is connected to.
ca_cert (string) (optional) (default: not used)
PEM-encoded certificate authorities. When set, a certificate pool will be created by appending the certificates to the system pool.
See file variable substitution for how to read this value from a file.
engine (optional, table engine settings. Default: MergeTree engine)
Engine to be used for tables. Only *MergeTree family is supported at the moment.
batch_size (integer) (optional) (default: 10000)
Maximum number of items that may be grouped together to be written in a single write.
batch_size_bytes (integer) (optional) (default: 5242880 (= 5 MiB))
Maximum size of items that may be grouped together to be written in a single write.
batch_timeout (duration) (optional) (default: 20s)
Maximum interval between batch writes.

ClickHouse table engine

This option allows to specify a custom table engine to be used.

name (string) (required)
Name of the table engine. Only *MergeTree family is supported at the moment.
parameters (array of parameters) (optional) (default: empty)
Engine parameters. Currently, no restrictions are imposed on the parameter types.

kind: destination
spec:
  name:       "clickhouse"
  path:       "cloudquery/clickhouse"
  registry:   "cloudquery"
  version:    "v4.0.6"
  write_mode: "append"

  spec:
    connection_string: "clickhouse://${CH_USER}:${CH_PASSWORD}@localhost:9000/${CH_DATABASE}"
    engine:
      name: ReplicatedMergeTree
      parameters:
      - "/clickhouse/tables/{shard}/{database}/{table}"
      - "{replica}"

Connecting to ClickHouse Cloud

To connect to ClickHouse Cloud, you need to set the secure=true parameter, username is default, and the port is 9440. Use a connection string similar to:

connection_string: "clickhouse://default:${CH_PASSWORD}@<your-server-id>.<region>.<provider>.clickhouse.cloud:9440/${CH_DATABASE}?secure=true"

See Quick Start: Using the ClickHouse Client for more details.

Verbose logging for debug

The ClickHouse destination can be run in debug mode. To achieve this pass the debug=true option to connection_string. See SDK documentation for more details.

Note: This will use SDK built-in logging and might output data and sensitive information to logs. Make sure not to use it in production environment.

kind: destination
spec:
  name:       "clickhouse"
  path:       "cloudquery/clickhouse"
  registry:   "cloudquery"
  version:    "v4.0.6"
  write_mode: "append"

  spec:
    connection_string: "clickhouse://${CH_USER}:${CH_PASSWORD}@localhost:9000/${CH_DATABASE}?debug=true"

Types

Apache Arrow type conversion

The ClickHouse destination plugin supports most of Apache Arrow types. It uses the same approach as documented in ClickHouse reference. The following table shows the supported types and how they are mapped to ClickHouse data types.

Unsupported types are always mapped to String.

Arrow Column Type	ClickHouse Type
Binary	String
Binary View	String
Boolean	Bool
Date32	Date32
Date64	DateTime
Decimal128 (Decimal)	Decimal
Decimal256	Decimal
Fixed Size Binary	FixedString
Fixed Size List	Array
Float16	Float32
Float32	Float32
Float64	Float64
Int8	Int8
Int16	Int16
Int32	Int32
Int64	Int64
Large Binary	String
Large List	Array
Large String	String
List	Array
Map	Map
String	String
String View	String
Struct	Tuple
Time32	DateTime64
Time64	DateTime64
Timestamp	DateTime64
UUID (CloudQuery extension)	UUID
Uint8	UInt8
Uint16	UInt16
Uint32	UInt32
Uint64	UInt64

Nested ClickHouse types have their values converted according to the aforementioned rules.