Azure Database for MySQL
An Azure managed MySQL database service for app development and deployment.
Azure MySQL Flexible Server: Enable binlog_row_metadata=FULL
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Divyanshu Sharma
0
Reputation points
• Root Cause: Azure MySQL Flexible Server locks the binlog_row_metadata parameter at MINIMAL, but Microsoft Fabric EventStream (Debezium) requires FULL metadata to parse JSON columns from the binary log.
• Why It Fails: With MINIMAL metadata, Debezium receives binlog events but cannot determine the data types of columns. For JSON columns specifically, it cannot decode the binary JSON format stored in the binlog, causing a schema mismatch error: "internal schema size 256, but row size 1".
• What Works vs Fails: Initial snapshot succeeds (uses direct SQL queries), and CDC works fine for tables without JSON columns or when JSON columns contain NULL. CDC fails only when UPDATE/INSERT operations include actual JSON data in the 3 affected columns.
• Solution: Request Azure support to enable binlog_row_metadata = FULL on both primary and read replica servers.
Azure Database for MySQL
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Pilladi Padma Sai Manisha 500 Reputation points Microsoft External Staff Moderator2025-12-08T19:30:51.66+00:00 Thank you for reaching out to Microsoft QA!
It looks like you're facing an issue with the
binlog_row_metadataparameter being locked at MINIMAL for Azure MySQL Flexible Server, and this is affecting your use of Microsoft Fabric EventStream (Debezium) for handling JSON columns.Currently, Azure MySQL Flexible Server does not allow you to change the
binlog_row_metadatasetting to FULL as you're requesting. Since it is locked at MINIMAL, Debezium's inability to interpret JSON column data is leading to the schema mismatch errors you're seeing. Unfortunately, without the FULL metadata, Debezium cannot effectively read the data types, particularly for JSON.At this moment, the best course of action would be to reach out directly to Azure support, as you've mentioned in your request for enabling
binlog_row_metadata = FULLon both your primary and read replica servers. This might not be a self-service feature, and Azure support would be the right path to potentially allow this configuration.Here are a couple of things you might also consider while waiting for a response from Azure support:
Workaround with JSON Handling: If there's a possibility to modify how you manage and utilize JSON columns, perhaps revisiting how data is handled or stored might mitigate some issues until a solution is found. Monitor Updates from Azure: Keep up with Azure updates as they might provide flexibility or solutions in future releases. If you need further assistance or have more specific scenarios you’d like to discuss, here are some follow-up questions that might be helpful:
What specific version of Azure MySQL Flexible Server are you using? Are there specific configurations or use cases that you would like to achieve with the FULL metadata? Have you tested any alternative methods to replicate your data without relying on JSON processing? Hope this helps clarify your situation! If you need more assistance, feel free to ask!
References:
Azure Database for MySQL - Flexible server business continuity overview Server parameters in Azure Database for MySQL - Flexible Server
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