PolarDB for MySQL to PolarDb for MySQL

BladePipe supports data replication from PolarDB for MySQL to PolarDb for MySQL. View supported migration, sync, verification, and connector capabilities.

Target DataSource：

PolarDb for MySQL

Connection

Basic Functions

Function	Description
Schema Migration	If the target schema does not exist, BladePipe will automatically generate and execute CREATE statements based on the source metadata and the mapping rule.
Full Data Migration	Migrate data by sequentially scanning data in tables and writing it in batches to the target database.
Incremental Data Sync	Sync of common DML like INSERT, UPDATE, DELETE is supported.
Data Verification and Correction	Verify all existing data. Optionally, you can correct the inconsistent data based on verification results. Scheduled DataTasks are supported. For more information, see Create Verification and Correction DataJob.
Subscription Modification	Add, delete, or modify the subscribed tables with support for historical data migration. For more information, see Modify Subscription.
Position Resetting	Reset positions by file position or timestamp. Allow re-consumption of incremental data logs in a past period or since a specific Binlog file and position.
Table Name Mapping	Support the mapping rules, namely, keeping the name the same as that in Source, converting the text to lowercase, converting the text to uppercase, truncating the name by "_digit" suffix.
DDL Synchronization	ALTER TABLE ADD COLUMN, DROP COLUMN, MODIFY COLUMN, CHANGE COLUMN ADD INDEX RENAME TABLE CREATE TABLE (whole database sync) Table partitioning Other compatible DDL
Metadata Retrieval	Retrieve the target metadata with filtering conditions or target primary keys set from the source table.

Advanced Functions

Function	Description
Incremental Data Write Conflict Resolution Rule	IGNORE: Ignore conflicts (skip writing), REPLACE: Replace the entire row in case of conflicts.
Handling of Zero Value for Time	Allow setting zero value for time to different data types to prevent errors when writing to the Target.
Online DDL Compatibility	Support GH-OST, PT-OSC, Aliyun DMS Online DDL.
Scheduled Full Data Migration	For more information, see Create Scheduled Full Data DataJob.
Custom Code	For more information, see Custom Code Processing, Debug Custom Code and Logging in Custom Code.
Data Filtering Conditions	Support data filtering using WHERE conditions, with SQL-92 as the SQL language. For more information, see Data Filtering.
Setting Target Primary Key	Change the primary key to another field to facilitate data aggregation and other operations.

Limits

Limit	Description
Character Set	Support utf8, utf8mb4, latin1. Other encodings have not been tested.

FAQ

How to handle MySQL DataJob latency?
What to do when binary Log cannot be found in MySQL Source?
What to do when access to schema in MySQL Source is denied?
Tips: MySQL source-related FAQs are also applicable to MySQL-compatible data sources.

Source

Prerequisites

Prerequisite	Description
Permissions for Account	A privileged account or a normal account with read and write permissions of PolarDbMySQL.
Enable Binlog	In the PolarDbMySQL instance, click Details > Configuration and Management > Parameter Configuration > Set the value of loose_polar_log_bin to true.
Character Set	Support utf8, utf8mb4, latin1. Other encodings have not been tested.

Parameters

Parameter	Description
parseBinlogParallel	Number of threads for parallel parsing of Binlog in Incremental DataJobs.
parseBinlogBufferSize	Size of the circular buffer for parsing Binlog in Incremental DataJobs.
maxTransactionSize	Maximum number of data rows per transaction. If exceeded, the transaction will be split and flushed in parts.
limitThroughputMb	Limit the throughput of incremental Binlogs.
extraDDL	Support synchronization of additional DDL, including PT, GHOST, ALI_DMS, and PT_GHOST.
needJsonEscape	Escape special characters in JSON to be written to the target database.

Tips: To modify the general parameters, see General Parameters and Functions.

Target

Prerequisites

Prerequisite	Description
Permissions for Account	A privileged account or a normal account with read and write permissions of PolarDbMySQL.
Port Preparation	Allow the migration and sync node (Worker) to connect to the PolarDbMySQL port (e.g., 3306).

Parameters

Parameter	Description
keyConflictStrategy	Strategy for handling primary key conflicts during write in Incremental DataTask: IGNORE: Ignore conflicts (default) REPLACE: Replace conflicts (optional)
dstWholeReplace	Convert INSERT and UPDATE operations into full row replacement in the Target.
mergeMaxInsertSize	When the parallel strategy mergeMaxInsertSize is set to TABLE_IMPORT_OPTIMIZE, it defines the maximum number of rows to merge per batch for the same table (improve parallelism).

Parameter

Description

keyConflictStrategy

Strategy for handling primary key conflicts during write in Incremental DataTask:

IGNORE: Ignore conflicts (default)
REPLACE: Replace conflicts (optional)

dstWholeReplace

Convert INSERT and UPDATE operations into full row replacement in the Target.

mergeMaxInsertSize

When the parallel strategy mergeMaxInsertSize is set to TABLE_IMPORT_OPTIMIZE, it defines the maximum number of rows to merge per batch for the same table (improve parallelism).

Tips: To modify the general parameters, see General Parameters and Functions.