Link to MyCAT

MyCAT is an open-source distributed database system. Its core function is to split a large table into multiple small tables and store them in the backend MySQL or other databases. Table 1 lists the parameters for a MyCAT link.

**Table 1** MyCAT link parameters
Parameter	Description	Example Value
Name	Link name, which should be defined based on the data source type, so it is easier to remember what the link is for	mycat_link
Database Server	IP address or domain name of the database to connect Click Select next to the text box and select a DWS or RDS DB instance in the displayed dialog box.	192.168.0.1
Port	Port of the database to connect	3306
Database Name	Name of the database to connect	dbname
Username	Username used for accessing the database This account must have the permissions required to read and write data tables and metadata.	cdm
Password	Password of the username	-
Use Local API	(Optional) Whether to use the local API of the database for acceleration. When you create a link, CDM automatically enables the local_infile system variable of the MySQL database to enable the LOAD DATA function, which accelerates data import to the MySQL database. If CDM fails to enable this function, contact the database administrator to enable the local_infile system variable. Alternatively, set Use Local API to No to disable API acceleration.	Yes
Create Backend Links	Whether to create backend links	Yes
managerUsername	MyCAT management username	root
managerPassword	MyCAT management password	123456
managerPort	MyCAT management port	9066
Backend Data Source	Type of the MyCAT backend database	MySQL
backendUsername	Username of the MyCAT backend database	cdm
backendPassword	Password of the MyCAT backend database	-
Fetch Size	(Optional) Displayed when you click Show Advanced Attributes. Number of rows obtained by each request. Set this parameter based on the data source and the job's data size. If the value is either too large or too small, the job may run for a long time.	1000
Link Attributes	(Optional) Click Add to add the JDBC connector attributes of multiple specified data sources. For details, see the JDBC connector document of the corresponding database.	sslmode=require
Reference Sign	(Optional) Delimiter between the names of the referenced tables or columns. For details, see the product documentation of the corresponding database.	'