Limitations and considerations

The following limitations apply:

• The following DDLs are not supported:

  • All partition DDLs
  • Drop Table
  • Rename Table

• Changes that are older than one year will not be captured.

• Using the alter table <table_name> add column <column_name> statement to add columns to the beginning or to the middle of a table is not supported. When the alter table <table_name> add column <column_name> statement is used to add a column to the middle of a table, the column will be added to the end of the table instead.
• The AR_H_USER header column is currently not supported. For information on using header columns, see Headers.
• If an Google Cloud SQL for MySQL table contains LOBs and the task's Replicate Lob columns option is disabled, the table will be replicated without the LOB columns. Note that this only applies to MEDIUMBLOB, LONGBLOB, MEDIUMTEXT and LONGTEXT columns. This limitation does not apply to BLOB, TINYBLOB, TEXT and TINYTEXT columns.
• If the Google Cloud SQL for MySQL database is stopped during Full Load, the Full Load will end successfully, but the tables on the target may have less rows than the source tables. If this should happen, either restart the task or reload the tables with the missing rows.

• A Unique Index/Primary Key created on only part of the column data is not supported. If such a Unique Index/Primary Key is encountered, it will be created on the entire target column.

  The following is an example of a statement that creates a Unique Index/Primary Key using only part of the column data:

  CREATE INDEX partial_name ON customer (name(10));

• Changes to computed (virtual) columns will not be captured.
• Replicate supports zero dates only if both the source and target MySQL-based databases are configured with the same "Strict Mode" (On or Off). If this is not the case, zero dates can be transformed to non-zero dates using the transformation feature.
• The Transaction ID of XA transactions will not be displayed in the replication ChangeTable/Audit Table transaction_id header.

• Binary log transaction compression is not supported.

• The MySQL primary-primary configuration is not supported.

• Failover of cluster nodes is not supported.

• Capturing changes from an encrypted binlog is not supported.

• Due to an issue with MySQL ODBC Driver 8.0.027 or later, empty TEXT columns may not be replicated correctly during Full Load. For example, if one table row contains a TEXT column with a value and the same column in the next row contains an empty value (but not NULL), both rows will display the value of the first row on the target.