MySQL CDC Connector rules and guidelines

Review the MySQL CDC Connector rules and guidelines before you begin creating connections, mappings, and mapping tasks.

•MySQL CDC connections are for sources only. Do not specify a MySQL CDC connection for a target.

•MySQL CDC Connector connects to a PowerExchange Listener on the PowerExchange system by using the Listener Location property in the MySQL CDC connection definition. On the Connector system, you do not need to create a local copy of the DBMOVER configuration file that contains a NODE statement pointing to the PowerExchange Listener.

•If you upgrade your system to a later PowerExchange version, you must stop the Secure Agent that connects to the older PowerExchange Listener before you try to connect to the upgraded PowerExchange Listener. After you edit the connection properties to specify the upgraded PowerExchange Listener, restart the Secure Agent before you try to establish the connection again. For more information, see Upgrading to a new version of PowerExchange.

•PowerExchange does not capture change data from MySQL columns that have a spatial data type. Spatial data types include geometery, point, linestring, polygon, multipoint, multilinestring, multipolygon, and geometrycollection. Any columns that have these data types will not be included in the change records that MySQL CDC Connector retrieves from PowerExchange.

Also, PowerExchange truncates column data that is longer that 98,304 bytes in columns that have any of the following data types: enum, json, longblob, longtext, mediumblob, mediumtext, set, varbinary, and varchar.

•The PowerExchange Listener can compress or encrypt the change data that it sends to the PWX CDC Reader component of MySQL CDC Connector, depending on how you set the Compression and Encryption properties for the connection.

•MySQL CDC Connector supports PowerExchange Logger group definition files. A group definition file creates a separate set of PowerExchange Logger log files for each defined group of registered MySQL source tables. When a mapping task runs, the PWX CDC Reader reads only the subset of log files for the group that contains the source table.

•If you include multiple MySQL source tables in a mapping, the PWX CDC Reader automatically uses group source processing to read change records for all of the tables in a single pass.

•The PWX CDC Metadata Adapter retrieves information for registered MySQL source tables from the PowerExchange extraction-map metadata file, CAMAPS. The Adapter retrieves information only from PowerExchange-generated extraction maps that have names beginning with "d." The extraction maps provide information, such as the incoming fields, that will be used when you create a mapping. The Adapter does not retrieve information from user-defined extraction maps that have names beginning with "u" for user-defined.

• The PowerExchange change data extraction modes, as defined in the PowerExchange CDC Guide for Linux, UNIX, and Windows, do not pertain to the MySQL CDC Connector. The PWX CDC Reader component of MySQL CDC Connector extracts change records until it reaches the end-of-log in the PowerExchange Logger log files and then stops. However, the PowerExchange configuration that the PWX CDC Reader requires is similar to the configuration for continuous extraction mode in the following ways:

- A CAPX CAPI_CONNECTION statement must exist in the PowerExchange DBMOVER configuration file.
- The capture registrations for MySQL source tables must specify Part for the Condense option.

• The maximum network buffer size that the PowerExchange Listener can use for sending data is 8 MB. If you have a mapping with an extremely large MySQL source table, this maximum buffer size might be exceeded. In this case, the mapping task fails with the following error:

PWXPC_10034 [date time] [ERROR] CDCDispatcher cannot fetch changed data from the PowerExchange Listener. Error code: [271]

•If you change the source object in a mapping that has been used for CDC processing, create a new mapping task for the mapping. If you need to retain the mapping task that is currently associated with the mapping, increment the revision number in the CDC Runtime properties for the mapping task.