As we are just a week away from Debezium 2.6.0.Final, I am pleased to announce Debezium 2.6.0.CR1, the first release candidate for the 2.6 release stream. This release includes a number of improvements, including XML support for the Oracle OpenLogReplicator adapter, TRACE level logging support for Debezium Server, configurable partition modes for Cassandra, the new Snapshot API for MongoDB and Db2, and more.

Additionally, this release includes a variety of bug fixes and several breaking changes.

Let’s take a closer look at all these changes and improvements included in Debezium 2.6.0.CR1; as always, you can find the complete list of changes for this release in the release notes. Please remember to take special note to any breaking changes that could affect your upgrade path.

Breaking changes

While we strive to avoid breaking changes, sometimes those changes are inevitable to evolve the right direction. This release includes several breaking changes.


The MysQL driver was updated to version 8.3.0, and this driver is not compatible with MySQL 5.x. If you still need to use an older MySQL version, please downgrade the driver after installation to a version that is compatible with your database (DBZ-7652).

SQL Server

The SQL Server connector was not capturing all schemas when the connector was first deployed, and instead, was only capturing the schemas based on the tables defined in the configuration’s include list. This was a bug that could prevent users from easily adding new tables to the connector when expecting that the new table’s schema would already exist in the schema history topic. The connector now correctly honors the store.only.captured.tables.ddl configuration option (DBZ-7593).

For existing connector deployments, if you do not specifically set the store.only.captured.tables.ddl property for the schema history topic, the connector will begin capturing schema changes for all relevant tables in your database. If you want to prevent this and retain the prior behavior, you will need to adjust your connector configuration by adding with a value of true.


The Vitess connector previously used the timestamp of BEGIN message as the source timestamp. This has been changed to the usage of the COMMIT timestamp to reflect the behaviour of other connectors (DBZ-7628).

New features and improvements

Debezium 2.6.CR1 also introduces more improvements and features, lets take a look at each individually.

XML Support for OpenLogReplicator

The Debezium for Oracle connector supports connections with OpenLogReplicator, allowing Oracle users to stream changes directly from the transaction logs. The latest build of OpenLogReplicator, version 1.5.0 has added support for XML column types.

To get started streaming XML with OpenLogReplicator, please upgrade the OpenLogReplicator process to 1.5.0 and restart the replicator process. Be aware that if you want to stream binary-based XML column data, you will need to toggle this feature as enabled in the OpenLogReplicator configuration.

TRACE level logging for Debezium Server

Debezium Server is a ready-made runtime for Debezium source connectors that uses the Quarkus framework to manage the source and sink deployments. As most Debezium Server users are aware who have reached out with questions or bugs, we often ask for TRACE-level logs and this has often proven difficult as it requires a full rebuild of Debezium Server due to how minimum logging level is a build-time configuration in Quarkus.

With Debezium 2.6.0.CR1 release and later, this will no longer be required. The build time configuration has been adjusted by default to include TRACE logging levels, so moving forward users can simply set the log level to TRACE and restart Debezium Server to obtain the logs (DBZ-7369).

New Unified Snapshot Modes

The snapshot process is an integral part of each connector’s lifecycle, and it’s responsible for collecting and sending all the historical data that exists in your data store to your target systems, if desired. For Debezium users who work with multiple connector types, we understand that having differing snapshot modes across connectors can sometimes be confusing to work with. So this change is designed to address that.

For many of you who may have already tried or installed Debezium 2.6 pre-releases, you’re already using the unified snapshot SPI as it was designed to be a drop-in-replacement initially, requiring no changes. This release finishes that work for MongoDB and DB2.

Of these changes, the most notable include the following:

  • All snapshot modes are available to all connectors, excluding never which remains specific to MySQL. This means that connectors that may have previously not supported a snapshot mode, such as when_needed, can now use this mode to retake a snapshot when the connector identifies that its necessary.

  • The schema_only_recovery mode has been deprecated and replaced by recovery.

  • The schema_only mode has also been deprecated and replaced by no_data.

All deprecated modes will remain available until Debezium 3 later this year. This provides users with about six months to adjust scripts, configurations, and processes in advance.

Cassandra configurable partition modes

When a Debezium Cassandra connector read the commit logs, events are processed sequentially and added to a queue. If multiple queues exist, events become distributed between these queues based on the hash of the commit log filename. This resulted in situations where events could be emitted in non-chronological order.

With Debezium 2.6, the Cassandra connector’s hashing algorithm now uses the partition column names to resolve the queue index for insertion. This should provide a more stable insert order so that events are emitted in the correct order.

A new configuration option has been added to opt-in to this new behavior. Debezium users can add the new configuration property event.order.guarantee.mode set to partition_values to take advantage of this new mode. By default, the property retains the old behavior using a default of commitlog_file.

Other fixes

In addition, there were quite a number of stability and bug fixes that made it into this release. These include the following:

  • Log Mining Processor advances SCN incorrectly if LogMiner query returns no rows DBZ-6679

  • debezium-connector-jdbc occurred java.sql.SQLException: ORA-01461: can bind a LONG value only DBZ-6900

  • Align snapshot modes for MongoDB DBZ-7304

  • Align snapshot modes for DB2 DBZ-7305

  • Align all snapshot mode on all connectors DBZ-7308

  • Oracle connector unable to find SCN after Exadata maintenance updates DBZ-7389

  • Oracle LOB requery on Primary Key change does not work for all column types DBZ-7458

  • Incorrect value of TIME(n) replicate from MySQL if the original value is negative DBZ-7594

  • Re-select Post Processor not working for complex types DBZ-7596

  • Null instead of toast placeholder written for binary types when "hex" mode configured DBZ-7599

  • Poor snapshot performance during schema snapshot DDL processing DBZ-7608

  • Remove LogMiner continuous mining configuration option DBZ-7610

  • Re-select post processor performance DBZ-7611

  • Uncaught exception during config validation in Engine DBZ-7614

  • Enhanced event timestamp precision combined with ExtractNewRecordState not working DBZ-7615

  • Incremental snapshot query doesn’t honor message.key.columns order DBZ-7617

  • Metric ScnFreezeCount never increases DBZ-7619

  • JDBC connector does not process ByteBuffer field value DBZ-7620

  • Update Quarkus Outbox to Quarkus 3.8.2 DBZ-7623

  • Upgrade Debezium Server to Quarkus 3.2.10 DBZ-7624

  • MongoDbReplicaSet and MongoDbShardedCluster should not create a new network for each builder instance by default DBZ-7626

  • Cassandra can have misaligned Jackson dependencies DBZ-7629

  • Remove forgotten lombok code from system tests DBZ-7634

  • Numerci value without mantissa cannot be parsed DBZ-7643

  • Add JDBC connector to artifact server image preparation DBZ-7644

  • Revert removal of Oracle LogMiner continuous mining DBZ-7645

  • Add documentation for MongoDB capture.mode.full.update.type property DBZ-7647

  • Missing test annotation in PostgresConnectorIT DBZ-7649

  • Fix MySQL image fetch for tests DBZ-7651

  • RedisSchemaHistoryIT continually fails DBZ-7654

  • Upgrade Quarkus Outbox Extension to Quarkus 3.8.3 DBZ-7656

  • Bump SQL Server test image to SQL Server 2022 DBZ-7657

  • Upgrade Debezium Server to Quarkus 3.2.11.Final DBZ-7662

  • Update QOSDK and Quarkus to fix vcs-url annotation CVE DBZ-7664

  • Exclude jcl-over-slf4j dependency DBZ-7665

  • MySQL connector fails to parse DDL with RETURNING keyword DBZ-7666

  • Schema history comparator doesn’t handle SERVER_ID_KEY and TIMESTAMP_KEY properly DBZ-7690

  • Duplicate envar generated in operator bundle DBZ-7703

What’s next?

We have just over a week before the Debezium 2.6 final release. If you have not given any of the latest pre-releases a try, we encourage everyone to do so and provide feedback if you face any problems or issues deploying this release candidate. Our goal is to release the 2.6.0.Final build immediately after the upcoming holiday break.

As the team begins to shift gears toward Debezium 2.7, here’s a speak peek at some upcoming highlights:

  • Standalone, Official MariaDB connector

  • User-friendly offset manipulation

  • Read-only incremental snapshots for all relational connectors

  • Sneak peek at the first PoC of the Debezium Server UI

For more details, please check out our road map for all upcoming details around Debezium 2.7 and beyond.

As always, please be sure to get in touch with us on the mailing list or Zulip chat if you have questions or feedback. We’re interested to know what you’d like to see changed in Debezium 3, so let us know!

Until next time…​

Chris Cranford

Chris is a software engineer at Red Hat. He previously was a member of the Hibernate ORM team and now works on Debezium. He lives in North Carolina just a few hours from Red Hat towers.


About Debezium

Debezium is an open source distributed platform that turns your existing databases into event streams, so applications can see and respond almost instantly to each committed row-level change in the databases. Debezium is built on top of Kafka and provides Kafka Connect compatible connectors that monitor specific database management systems. Debezium records the history of data changes in Kafka logs, so your application can be stopped and restarted at any time and can easily consume all of the events it missed while it was not running, ensuring that all events are processed correctly and completely. Debezium is open source under the Apache License, Version 2.0.

Get involved

We hope you find Debezium interesting and useful, and want to give it a try. Follow us on Twitter @debezium, chat with us on Zulip, or join our mailing list to talk with the community. All of the code is open source on GitHub, so build the code locally and help us improve ours existing connectors and add even more connectors. If you find problems or have ideas how we can improve Debezium, please let us know or log an issue.