Scenarios

Currently, HetuEngine supports the interconnection with the ClickHouse data source in the cluster of MRS 3.1.1 or later.
The HetuEngine cluster in security mode supports the interconnection with the ClickHouse data source in the cluster of MRS 3.1.1 or later in security mode.
The HetuEngine cluster in normal mode supports the interconnection with the ClickHouse data source in the cluster of MRS 3.1.1 or later in normal mode.
In the ClickHouse data source, tables with the same name but in different cases, for example, cktable (lowercase), CKTABLE (uppercase), and CKtable (uppercase and lowercase), cannot co-exist in the same schema or database. Otherwise, tables in the schema or database cannot be used by HetuEngine.

Prerequisites

You have created a HetuEngine administrator by referring to Creating a HetuEngine User.

Procedure

Log in to FusionInsight Manager as a HetuEngine administrator and choose Cluster > Services > HetuEngine. The HetuEngine service page is displayed.
In the Basic Information area on the Dashboard tab page, click the link next to HSConsole WebUI. The HSConsole page is displayed.
Choose Data Source.

Click Add Data Source. On the Add Data Source page that is displayed, configure parameters.

Configure parameters in the Basic Configuration area. For details about the parameters, see Table 1.

**Table 1** Basic Information
Parameter	Description	Example Value
Name	Name of the data source to be connected. The value can contain only letters, digits, and underscores (_) and must start with a letter.	clickhouse_1
Data Source Type	Type of the data source to be connected. Choose JDBC > ClickHouse.	ClickHouse
Description	Description of the data source. The value can contain only letters, digits, commas (,), periods (.), underscores (_), spaces, and line breaks.	-

Configure parameters in the ClickHouse Configuration area. For details, see Table 2.

**Table 2** ClickHouse Configuration
Parameter	Description	Example Value
Driver	The default value is clickhouse.	clickhouse
JDBC URL	JDBC URL of the ClickHouse data source. If the ClickHouse data source uses IPv4, the format is jdbc:clickhouse://<host>:<port>. If the ClickHouse data source uses IPv6, the format is jdbc:clickhouse://[<host>]:<port>. To obtain the value of <host>, log in to Manager of the cluster where the ClickHouse data source is located, choose Cluster > Services > ClickHouse > Instance, and view the ClickHouseBalancer service IP address. To obtain the value of <port>, log in to Manager of the cluster where the ClickHouse data source is located, and choose Cluster > Services > ClickHouse > Configurations > All Configurations. If the ClickHouse data source is in security mode, check the HTTPS port number of the ClickHouseBalancer instance, that is, the value of lb_https_port. If the ClickHouse data source is in normal mode, check the HTTP port number of the ClickHouseBalancer instance, that is, the value of lb_http_port.	jdbc:clickhouse://10.162.156.243:21426, jdbc:clickhouse://10.162.156.243:21425, or jdbc:clickhouse://[fec0::d916:8:5:164:200]:21426
Username	Username used for connecting to the ClickHouse data source.	Change the value based on the username being connected with the data source.
Password	User password used for connecting to the ClickHouse data source.	Change the value based on the user password for connecting to the data source.
Case-sensitive Table/Schema Name	Whether to support case-sensitive names or schemas of the data source. HetuEngine supports case-sensitive names or schemas of the data source. No: If multiple table names exist in the same schema of a data source, for example, cktable (lowercase), CKTABLE (uppercase), and CKtable (lowercase and uppercase), only cktable (lowercase) can be used by HetuEngine. Yes: Only one table name can exist in the same schema of the data source, for example, cktable (lowercase), CKTABLE (uppercase), or CKtable (lowercase and uppercase). Otherwise, all tables in the schema cannot be used by HetuEngine.	-

(Optional) Customize the configuration.

You can click Add to add custom configuration parameters. Configure custom parameters of the ClickHouse data source. For details, see Table 3.

**Table 3** Custom parameters of the ClickHouse data source
Parameter	Description	Example Value
use-connection-pool	Whether to use the JDBC connection pool.	true
jdbc.connection.pool.maxTotal	Maximum number of connections in the JDBC connection pool.	8
jdbc.connection.pool.maxIdle	Maximum number of idle connections in the JDBC connection pool.	8
jdbc.connection.pool.minIdle	Minimum number of idle connections in the JDBC connection pool.	0
jdbc.connection.pool.testOnBorrow	Whether to check the connection validity when using a connection obtained from the JDBC connection pool.	false
jdbc.pushdown-enabled	Whether to enable the pushdown function. Default value: true	true
jdbc.pushdown-module	Pushdown type. DEFAULT: No operator is pushed down. BASE_PUSHDOWN: Only operators such as Filter, Aggregation, Limit, TopN, and Projection are pushed down. FULL_PUSHDOWN: All supported operators are pushed down.	-
clickhouse.map-string-as-varchar	Whether to convert the ClickHouse data source of the String and FixedString types to the Varchar type. Default value: true	true
clickhouse.socket-timeout	Timeout interval for connecting to the ClickHouse data source. Unit: millisecond Default value: 120000	120000
case-insensitive-name-matching.cache-ttl	Timeout interval for caching case-sensitive names of schemas or tables of the data sources. Unit: minute Default value: 1	1

You can click Delete to delete custom configuration parameters.

Click OK.

Operation Guide

Table 4 lists the ClickHouse data types supported by HetuEngine.

**Table 4** ClickHouse data types supported by HetuEngine
Name	ClickHouse Data Type
ClickHouse data types supported by HetuEngine	UInt8	Decimal128(S)
	UInt16	Boolean
	UInt32	String
	UInt64	Fixedstring(N)
	Int8	UUID
	Int16	Date
	Int32	DateTime([timezone])
	Int64	Enum
	Float32	LowCardinality(data_type)
	Float64	Nullable(typename)
	Decimal(P, S)	IPv4
	Decimal32(S)	IPv6
	Decimal64(S)	-

Table 5 lists the tables and views that support the interconnection between HetuEngine and ClickHouse.

**Table 5** Supported tables and views
Name	Supported Table and View
Tables that support the interconnection between HetuEngine and ClickHouse	Local table (MergeTree)
	Replicated table (ReplicatedReplacingMergeTree)
	Distributed table
Views that support the interconnection between HetuEngine and ClickHouse	Normal view
	Materialized view

Configuring a ClickHouse Data Source

Scenarios

Prerequisites

Procedure

Operation Guide