MySQL GTID-Based Replication Monitoring
By Tom Nonmacher
Welcome to another post on SQLSupport.org.
There is often confusion when it comes to cross platform replication and monitoring. This post clarifies what GTID based replication in MySQL really involves, how to monitor it properly, and what tools or techniques are relevant, including some that are not.
What Is GTID Based Replication?
GTID stands for Global Transaction Identifier. It is a feature in MySQL that assigns a unique ID to every transaction committed on the primary server. This makes it easy to replicate those transactions to one or more replicas without needing to track file names or positions in the binary log.
GTID simplifies failover and consistency checks. Because each transaction is uniquely tagged, replicas can confirm that they have applied all necessary transactions just by comparing GTIDs. This is more resilient and self healing than traditional binlog file position based replication.
Can SQL Server Monitor GTIDs?
No. This is a fundamental misunderstanding.
GTID replication is specific to MySQL and MariaDB. SQL Server has its own replication models including transactional, snapshot, and merge, but it does not support GTIDs. Also, TSQL cannot query GTID status in MySQL. TSQL is a Microsoft SQL Server language and cannot natively connect to or query MySQL systems without using linked servers or external tooling.
How to Monitor GTID Based Replication in MySQL
You can monitor GTID replication in MySQL using native commands:
Useful fields include:
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Executed GTID Set: The GTIDs that have been executed on the server
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Retrieved GTID Set: GTIDs received but not yet executed
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Auto Position: Indicates whether GTID based replication is active
You can also run:
Replicating MySQL to Azure
Azure Database for MySQL Flexible Server supports GTID based data in replication. You can replicate from:
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On premises MySQL
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MySQL on virtual machines
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Cloud hosted MySQL instances
When using GTID based replication, there is no need to reference specific log files or positions. GTIDs handle that automatically. This makes replication setup and failover far simpler.
What About Replication Between MySQL and SQL Server?
This is where many teams get tripped up. GTID based replication cannot be used directly between MySQL and SQL Server. They have completely different engines and replication models.
However, replication between the two is possible, just not via GTID. Here are your options:
1. Change Data Capture Tools
Use third party tools like Oracle GoldenGate, Debezium, or CData Sync to capture changes from MySQL and apply them to SQL Server. These tools often support GTID tracking on the source side but convert it into their own change format.
2. Custom Replication Apps
You can develop an app that pulls GTID changes from MySQL and writes to SQL Server. This gives full control but requires handling consistency and conflict resolution.
3. ETL with SSIS
SQL Server Integration Services can be used to replicate data from MySQL to SQL Server on a schedule. This is not real time and does not preserve GTIDs. It is useful for periodic sync.
4. Azure Database Migration Service
If you are migrating from MySQL to Azure SQL Database or Azure SQL Managed Instance, Azure DMS offers guided migration support. Continuous sync may be supported, but again, GTIDs are not maintained in the target system.
Can GTID Metrics Be Used in AI or Observability Tools?
Yes, but only in the context of MySQL environments. You can forward GTID metrics to observability platforms like:
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Prometheus with mysqld_exporter
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Grafana for visualization
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Azure Monitor for Azure hosted MySQL
If you collect these metrics into a structured data source such as Delta Lake, you could build dashboards or apply machine learning to detect anomalies. But none of this involves SQL Server or TSQL directly.
Final Thoughts
Monitoring MySQL GTID based replication is crucial for ensuring data consistency and availability in modern distributed systems. But it is equally important to use the right tool for the job. While SQL Server is a powerful relational database platform, it does not support GTIDs and cannot be used to monitor MySQL replication directly.
If you are working with hybrid environments involving both MySQL and SQL Server, the key is to treat replication and monitoring as platform specific concerns, bridging them only through custom pipelines or third party tools.
Keep your monitoring accurate and your assumptions grounded.
Until next time,
Tom
The Data Whisperer