Synchronize data from PolarDB-X 2.0 to Lindorm

Source database

• The source server must have at least 100 Mb/s outbound bandwidth. Lower bandwidth reduces synchronization speed.

• The source cannot be a read-only PolarDB-X 2.0 Enterprise Edition instance.

• Schema synchronization is not supported.

• Tables with uppercase letters in their names cannot be synchronized.

• Tables whose names are SQL reserved words (such as select) cannot be synchronized.

• The TABLEGROUP attribute and any database or schema that contains the Locality attribute cannot be synchronized.

• BIT type data cannot be synchronized.

• You cannot synchronize only primary key fields — tables must contain at least one non-primary key field.

• Tables must have a PRIMARY KEY or UNIQUE constraint with all fields unique. Otherwise, duplicate records may appear in the destination database.

• If you select individual tables and need to rename tables or columns in the destination, a single sync task supports at most 5,000 tables. For more than 5,000 tables, configure multiple tasks in batches or sync at the database level.

• Binary logging (binlog) is enabled by default for PolarDB-X 2.0 instances. The binlog_row_image parameter on the source must be set to full. A different value causes a precheck failure and prevents the task from starting. See Parameter settings.

• Do not run DDL operations that change table or database schemas during the full data synchronization phase. DTS queries the source during this phase, which creates metadata locks that can block DDL operations.

• If the network configuration of the PolarDB-X 2.0 instance changes, the sync task may experience latency for a period of time.

Destination database and general

• DTS can only write data to LindormTable. Other Lindorm engines are not supported.

• VARBINARY empty strings are processed as null values in DTS and Lindorm.

• If the DECIMAL field precision in the destination Lindorm instance differs from the source, the task fails. Make sure the precision matches.

• The data written to Lindorm must meet Limits on data requests.

• DTS periodically runs CREATE DATABASE IF NOT EXISTS \`test\` on the source to write heartbeat data and advance the binlog offset. If you set Whether to delete SQL operations on heartbeat tables of forward and reverse tasks to Yes, or if the source database account lacks permission to create databases, synchronization latency information may become inaccurate when no DML operations occur for a long time.

  If the task shows a long latency, run a DML operation on the source database to refresh the latency display.

• During full data synchronization, DTS consumes read and write resources on both the source and destination databases, increasing the load. Run the sync during off-peak hours — ideally when CPU usage on both sides is below 30%.

• Full data synchronization uses concurrent INSERT operations, which can cause table fragmentation. The destination database may use more storage than the source after full sync completes.

• If data is written to the destination from sources other than DTS during synchronization, data inconsistency may occur and the sync task may fail.

• If a DTS instance fails, the DTS team attempts to recover it within 8 hours. Recovery operations may include restarting the instance and adjusting DTS instance parameters (not database parameters). For a list of parameters that may be modified, see Modify instance parameters.

Step 1: Go to the Data Synchronization page

Use one of the following consoles to open the Data Synchronization page.

Step 2: Configure source and destination databases

1. Click Create Task.

2. Configure the following parameters.

1. Click Test Connectivity and Proceed.

   DTS server CIDR blocks must be allowed in the security settings of both the source and destination databases. See Add DTS server IP addresses to a whitelist.

Step 3: Select sync objects

1. In the Configure Objects step, configure the parameters below.

1. Click Next: Advanced Settings.

Step 4: Configure advanced settings

Step 5: Save settings and run the precheck

1. (Optional) To view the API parameters that correspond to your configuration, hover over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.

2. Click Next: Save Task Settings and Precheck.

   DTS runs a precheck before starting the sync task. The task can start only after all precheck items pass. If the precheck fails, click View Details next to each failed item, fix the issues, and click Precheck Again. If an item triggers an alert that you choose to ignore, click Confirm Alert Details, then click Ignore in the dialog, click OK, and run the precheck again. Ignoring an alert may cause data inconsistency.

Step 6: Purchase the instance

1. Wait until Success Rate reaches 100%, then click Next: Purchase Instance.

2. On the purchase page, configure the following parameters.

1. Read and select Data Transmission Service (Pay-as-you-go) Service Terms.

2. Click Buy and Start, then click OK in the confirmation dialog.

You can view the task progress in the task list.