All Products
Search
Document Center

Data Transmission Service:Change tracking overview

Last Updated:Jun 06, 2026

The change tracking feature of Data Transmission Service (DTS) captures real-time incremental data from your databases. You can use this data for various purposes, such as writing it to a destination system. This enables various use cases, including cache updates, asynchronous decoupling of business components, real-time synchronization between heterogeneous data sources, and complex ETL workflows.

Source database limitations

Limitation

Description

Network requirements

  • The network bandwidth must be 100 Mb/s or higher.

  • The Round-Trip Time (RTT) between the source database and the DTS service must be less than 2 ms. A higher RTT degrades the performance of the change tracking task.

    For example, if a database in the Singapore region connects to DTS in the China (Hong Kong) region through a VPN, the long physical distance can cause a high RTT, leading to task latency.

Business requirements

  • The peak log volume must be less than 1 TB, with an average hourly log volume under 50 GB and peak traffic under 15 MB/s.

    Important

    By default, DTS pulls logs from the entire database instance. High-volume data changes in objects that are not part of the change tracking task can also cause task latency.

  • Batch data updates or large-scale changes to large object (LOB) data types, such as CLOB, BLOB, or LONG, may cause task latency. To prevent this, run these operations in smaller batches or avoid them when possible.

  • Avoid frequent DELETE or UPDATE operations on tables without a primary key to prevent task latency.

  • To prevent task latency, execute no more than 10 DDL statements per second.

  • Avoid large transactions. A single transaction that generates more than 100 GB of logs may cause the task to fail.

Change tracking plans

Note

Whether you can create a cross-account change tracking task depends on the source database type and access method. When configuring the task, you must set the Replicate Data Across Alibaba Cloud Accounts parameter to Yes for the source database. For more information, see Configure a cross-account DTS task.

Source database

Supported types

Documentation

  • self-managed MySQL

    Versions 5.1, 5.5, 5.6, 5.7, 8.0, and 8.4

  • ApsaraDB RDS for MySQL

    All versions

  • data update

  • schema update

Track data changes from an ApsaraDB RDS for MySQL instance

PolarDB for MySQL

All versions

  • data update

  • schema update

Create a PolarDB for MySQL change tracking task

PolarDB-X 1.0

Important

The underlying databases for PolarDB-X must be based on ApsaraDB RDS for MySQL. DTS does not support databases created on PolarDB for MySQL.

  • data update

  • schema update

Create a PolarDB-X 1.0 change tracking task

PolarDB-X 2.0

Important

The underlying databases for PolarDB-X must be based on ApsaraDB RDS for MySQL. DTS does not support databases created on PolarDB for MySQL.

  • data update

  • schema update

Create a PolarDB-X 2.0 change tracking task

PolarDB for PostgreSQL (Compatible with Oracle)

All versions

data update

Create a change tracking task for PolarDB for PostgreSQL (Compatible with Oracle)

self-managed Oracle (non-RAC architecture)

Versions 9i, 10g, and 11g

  • data update

  • schema update

Create an Oracle change tracking task

  • ApsaraDB RDS for PostgreSQL

    Versions 9.4, 10, 11, 12, 13, 14, 15, 16, 17, and 18

  • self-managed PostgreSQL

    Versions 9.4.8 and later, 9.5, 9.6, 10.x, 11.x, 12.x, 13.x, 14.x, 15.x, 16.x, 17.x, and 18.x

data update

Create an RDS PostgreSQL change tracking task

Data Management (DMS) logical database

Important

The logical database must consist of database shards from multiple PolarDB for MySQL instances.

data update

Create a DMS logical database change tracking task

PolarDB for PostgreSQL

Versions 11, 14, 15, 16, 17, and 18

  • data update

  • schema update

Create a change tracking task for PolarDB for PostgreSQL