PolarDB:Migration evaluation

Create an evaluation task

Start the evaluation from any of these entry points:

• Clusters page: Click Migrate/Upgrade Evaluation in the upper-left corner of the Clusters page.

• Migration/Upgrade page: Click Migration/Upgrade Evaluation in the upper-left corner of the Migration/Upgrade page.

• PolarDB buy page: Select Migrate from RDS, set Source RDS Version, Database Engine, and Database Edition, then click Migration Evaluation.

Configure the evaluation

Fill in the parameters and click Next.

Review results and fix issues

PolarDB evaluates your source instance and migration plan across the four categories. Review each result and fix all issues before proceeding.

DTS does not support event synchronization. If the event check result shows Existing, manually synchronize the events to the destination PolarDB cluster after migration.

After fixing all issues, click Continue to Buy or Buy to proceed to the PolarDB buy page. For the full migration procedure, see Upgrade an ApsaraDB RDS for MySQL instance to a PolarDB for MySQL cluster.

Event check (informational)

DTS does not support event synchronization. If the source RDS instance has events, manually synchronize them to the destination PolarDB cluster after migration. This finding does not block migration.

Basic Information Verification

Source Instance Running Status

The source ApsaraDB RDS instance must be in the Running state.

Source Instance Read/Write Status

The source ApsaraDB RDS instance must be in the Running state and in Read/Write mode.

Source Instance Account Mode

If Database Proxy (Safe Mode) is enabled for the ApsaraDB RDS for MySQL instance, create a privileged account or switch the network connection mode to high-performance mode. For details, see Create an account and RDS network link upgrade.

Service-linked Role for PolarDB

Create the service-linked role for PolarDB. For details, see Precheck whether the service-linked role for PolarDB is created. You can also create the role by calling the CreateServiceLinkedRole API.

Migration Task Dependency Verification

DTS Permissions

Grant your Alibaba Cloud account permissions to access cloud resources through DTS. For details, see Authorize DTS to access Alibaba Cloud resources.

Whether Source Instance is Empty

Create at least one database in the source ApsaraDB RDS instance before migration. For details, see Create a database.

Source Instance Table Engine Verification

The table storage engine must be InnoDB or X-Engine. Tables using other engines are not supported for migration.

Source Instance Trigger Verification

Delete all triggers from the source ApsaraDB RDS instance before migration — triggers interrupt the migration process. Run the following statements to list and delete triggers:

-- List all triggers in the source instance
SHOW TRIGGERS;
-- Delete a specific trigger
DROP TRIGGER trigger_name;

After migration completes, recreate the triggers on the destination PolarDB cluster.

Verification for Non-primary-key Tables in Source Instance

Tables without primary keys may result in duplicate data in the destination PolarDB cluster after synchronization. Run the following SQL statement to identify tables without primary keys:

SELECT t1.table_schema, t1.table_name
FROM information_schema.TABLES t1 LEFT OUTER
    JOIN information_schema.TABLE_CONSTRAINTS t2
    ON t1.table_schema = t2.TABLE_SCHEMA AND t1.table_name = t2.TABLE_NAME AND t2.CONSTRAINT_NAME
    IN ("PRIMARY")
WHERE t2.table_name IS NULL AND t1.table_type = "BASE TABLE" AND t1.TABLE_SCHEMA NOT IN ("information_schema", "performance_schema", "mysql", "sys")

Add primary keys to those tables. If duplicate data is acceptable for your use case, ignore this result and select Continue when prompted during the upgrade procedure.

Key Information Verification

Source Instance Root Account Verification

The root and aliyun_root accounts must not coexist in the source ApsaraDB RDS instance. If both accounts exist, system accounts in the destination PolarDB cluster may be overwritten during migration. For details, see Remove redundant system accounts from the source ApsaraDB RDS instance.