@Rocky We want to continuously sync incremental data from StarRocks into an OLTP database like PostgreSQL with insert/update (upsert) behavior. Is there any native StarRocks-supported approach, connector, CDC mechanism, or recommended architecture for this type of outbound synchronization?

Synchronizing data from StarRocks to an OLTP database like PostgreSQL with incremental "upsert" behavior is primarily achieved using the StarRocks Binlog feature in combination with Apache Flink. While StarRocks does not have a native "Push" button or a single SQL command to mirror a table to an external database, the following architecture is the standard and supported approach for outbound CDC (Change Data Capture). Recommended Architecture: Flink-based CDC The most robust approach for continuous outbound synchronization is: StarRocks (Binlog) → Flink (StarRocks Source) → PostgreSQL (JDBC Sink) 1. Enable Binlog in StarRocks Starting from StarRocks 3.0, you can enable the Binlog feature on a per-table basis. This allows external systems to consume a stream of changes (inserts, updates, deletes) from the table. • You must set the

binlog.enable

property to

true

when creating the table or by altering an existing table. • This is typically used with the Primary Key model to capture record-level changes effectively.

sql
-- Example: Enable binlog on an existing table
ALTER TABLE your_table SET ("binlog.enable" = "true");

2. Use the Flink StarRocks Connector as a Source The Flink-connector-starrocks (v1.2.9 or later) supports reading from StarRocks in Source mode by consuming these binlogs. • Source Config: In your Flink job, define a table using the

starrocks

connector. Flink will connect to the StarRocks FE/BE to fetch the change stream. • Sink Config: Define a second table in Flink using the standard

jdbc

connector pointing to your PostgreSQL instance. 3. Handle Upsert in PostgreSQL To achieve the "upsert" behavior in PostgreSQL: • Ensure your Flink SQL job uses an

INSERT INTO ... SELECT ...

statement between the StarRocks source and the PostgreSQL sink. • The Flink JDBC Sink handles upserts automatically for PostgreSQL if the target table has a primary key. It generates

INSERT ... ON CONFLICT (...) DO UPDATE SET ...

statements under the hood. ────────── Alternative Approaches * Third-Party Synchronization Tools: StarRocks documentation highlights several ecosystem tools that support StarRocks as a source for replication: * CloudCanal: Supports real-time incremental synchronization from StarRocks to PostgreSQL with a visual interface. * BladePipe: A data migration and synchronization tool often recommended for StarRocks ecosystem tasks. * Manual Batch Export (Non-Continuous): If real-time synchronization is not required, you can use the

EXPORT

command to save data to S3/HDFS and then load it into PostgreSQL. However, this does not support native CDC/incremental upserts out of the box. Important Limitations * External Table Writing: While StarRocks supports JDBC External Tables for PostgreSQL, these are currently read-only. You cannot use

INSERT INTO postgres_external_table SELECT ...

to sync data from StarRocks to PostgreSQL; this feature is only supported for writing from one StarRocks cluster to another. * Resource Usage: Enabling Binlog on a StarRocks table increases storage overhead (for the log files) and may have a minor impact on write performance. References • loading/Flink_cdc_load.md