June 2025 Recap: Azure Database for PostgreSQL
Hello Azure Community, We have introduced a range of exciting new features and updates to Azure Database for PostgreSQL in June. From general availability of PG 17 to public preview of the SSD v2 storage tier for High Availability, there have been some significant feature announcements across multiple areas in the last month. Stay tuned as we dive deeper into each of these feature updates. Before that, let’s look at POSETTE 2025 highlights. POSETTE 2025 Highlights We hosted POSETTE: An Event for Postgres 2025 in June! This year marked our 4th annual event featuring 45 speakers and a total of 42 talks. PostgreSQL developers, contributors, and community members came together to share insights on topics covering everything from AI-powered applications to deep dives into PostgreSQL internals. If you missed it, you can catch up by watching the POSETTE livestream sessions. If this conference sounds interesting to you and want to be part of it next year, don’t forget to subscribe to POSETTE news. Feature Highlights General Availability of PostgreSQL 17 with 'In-Place' upgrade support General Availability of Online Migration Migration service support for PostgreSQL 17 Public Preview of SSD v2 High Availability New Region: Indonesia Central VS Code Extension for PostgreSQL enhancements Enhanced role management Ansible collection released for latest REST API version General Availability of PostgreSQL 17 with 'In-Place' upgrade support PostgreSQL 17 is now generally available on Azure Database for PostgreSQL flexible server, bringing key community innovations to your workloads. You’ll see faster vacuum operations, richer JSON processing, smarter query planning (including better join ordering and parallel execution), dynamic logical replication controls, and enhanced security & audit-logging features—backed by Azure’s five-year support policy. You can easily upgrade to PostgreSQL 17 using the in-place major version upgrade feature available through the Azure portal and CLI, without changing server endpoints or reconfiguring applications. The process includes built-in validations and rollback safety to help ensure a smooth and reliable upgrade experience. For more details, read the PostgreSQL 17 release announcement blog. General Availability of Online Migration We're excited to announce that Online Migration is now generally available for the Migration service for Azure Database for PostgreSQL! Online migration minimizes downtime by keeping your source database operational during the migration process, with continuous data synchronization until cut over. This is particularly beneficial for mission-critical applications that require minimal downtime during migration. This milestone brings production-ready online migration capabilities supporting various source environments including on-premises PostgreSQL, Azure VMs, Amazon RDS, Amazon Aurora, and Google Cloud SQL. For detailed information about the capabilities and how to get started, visit our Migration service documentation. Migration service support for PostgreSQL 17 Building on our PostgreSQL 17 general availability announcement, the Migration service for Azure Database for PostgreSQL now fully supports PostgreSQL 17. This means you can seamlessly migrate your existing PostgreSQL instances from various source platforms to Azure Database for PostgreSQL flexible server running PostgreSQL 17. With this support, organizations can take advantage of the latest PostgreSQL 17 features and performance improvements while leveraging our online migration capabilities for minimal downtime transitions. The migration service maintains full compatibility with PostgreSQL 17's enhanced security features, improved query planning, and other community innovations. Public Preview of SSD v2 High Availability We’re excited to announce the public preview High availability (HA) support for the Premium SSD v2 storage tier in Azure Database for PostgreSQL flexible server. This support allows you to enable Zone-Redundant HA using Premium SSD v2 during server deployments. In addition to high availability on SSDv2 you now get improved resiliency and 10 second failover times when using Premium SSD v2 with zone-redundant HA, helping customers build resilient, high-performance PostgreSQL applications with minimal overhead. This feature is particularly well-suited for mission-critical workloads, including those in financial services, real-time analytics, retail, and multi-tenant SaaS platforms. Key Benefits of Premium SSD v2: Flexible disk sizing: Scale from 32 GiB to 64 TiB in 1-GiB increments Fast failovers: Planned or unplanned failovers typically around 10 seconds Independent performance configuration: Achieve up to 80,000 IOPS and 1,200 Mbps throughput without resizing your disk. Baseline performance: Free throughput of 125 MB/s and 3,000 IOPS for disks up to 399 GiB, and 500 MB/s and 12,000 IOPS for disks 400 GiB and above at no additional cost. For more details, please refer to the Premium SSD v2 HA blog. New Region: Indonesia Central New region rollout! Azure Database for PostgreSQL flexible server is now available in Indonesia Central, giving customers in and around the region lower latency and data residency options. This continues our mission to bring Azure PostgreSQL closer to where you build and run your apps. For the full list of regions visit: Azure Database for PostgreSQL Regions. VS Code Extension for PostgreSQL enhancements The brand-new VS code extension for PostgreSQL launched in mid-May and has already garnered over 122K installs from the Visual Studio Marketplace! And the kickoff blog about this new IDE for PostgreSQL in VS Code has had over 150K views. This extension makes it easier for developers to seamlessly interact with PostgreSQL databases. We have been committed to make this experience better and have introduced several enhancements to improve reliability and compatibility updates. You can now have better control over service restarts and process terminations on supported operating systems. Additionally, we have added support for parsing additional connection-string formats in the “Create Connection” flow, making it more flexible and user-friendly. We also resolved Entra token-fetching failures for newly created accounts, ensuring a smoother onboarding experience. On the feature front, you can now leverage Entra Security Groups and guest accounts across multiple tenants when establishing new connections, streamlining permission management in complex Entra environments. Don’t forget to update to the latest version in the marketplace to take advantage of these enhancements and visit our GitHub repository to learn more about this month’s release. If you learn best by video, these 2 videos are a great way to learn more about this new VS Code extension: POSETTE 2025: Introducing Microsoft’s VS Code Extension for PostgreSQL Demo of using VS code extension for PostgreSQL Enhanced role management With the introduction of PostgreSQL 16, a strict role hierarchy structure has been implemented. As a result, GRANT statements that were functional in PostgreSQL 11-15 may no longer work in PostgreSQL 16. We have improved the administrative flexibility and addressed this limitation in Azure Database for PostgreSQL flexible server across all PostgreSQL versions. Members of ‘azure_pg_admin’ can now manage, and access objects owned by any role that is non-restricted, giving control and permission over user-defined roles. To learn more about this improvement, please refer to our documentation on roles. Ansible collection released for latest REST API version A new version of Ansible collection for Azure Database for PostgreSQL flexible server is now released. Version 3.6.0 now includes the latest GA REST API features. This update introduces several enhancements, such as support for virtual endpoints, on-demand backups, system-assigned identity, storage auto-grow, and seamless switchover of read replicas to a new site (Read Replicas - Switchover), among many other improvements. To get started with using please visit flexible server Ansible collection link. Azure Postgres Learning Bytes 🎓 Using PostgreSQL VS code extension with agent mode The VS Code extension for PostgreSQL has been trending amongst the developer community. In this month's Learning Bytes section, we want to share how to enable the extension and use GitHub Copilot to create a database in Agent Mode, add dummy data, and visualize it using the Agent Mode and VS Code extension. Step 1: Download the VS code Extension for PostgreSQL Step 2: Check GitHub Copilot and Agent mode is enabled Go to File -> Preferences -> Settings (Ctrl + ,). Search and enable "chat.agent.enabled" and "pgsql copilot.enable". Reload VS Code to apply changes. Step 3: Connect to Azure Database for PostgreSQL Use the extension to enter instance details and establish a connection. Create and view schemas under Databases -> Schemas. Step 4: Visualize and Populate Data Right-click the database to visualize schemas. Ask the agent to insert dummy data or run queries. Conclusion That's all for the June 2025 feature updates! We are dedicated to continuously improve Azure Database for PostgreSQL with every release. Stay updated with the latest updates to our features by following this link. Your feedback is important and helps us continue to improve. If you have any suggestions, ideas, or questions, we’d love to hear from you. Share your thoughts here: aka.ms/pgfeedback We look forward to bringing you even more exciting updates throughout the year, stay tuned!July 2025 Recap: Azure Database for PostgreSQL
Hello Azure Community, July delivered a wave of exciting updates to Azure Database for PostgreSQL! From Fabric mirroring support for private networking to cascading read replicas, these new features are all about scaling smarter, performing faster, and building better. This blog covers what’s new, why it matters, and how to get started. Catch Up on POSETTE 2025 In case you missed POSETTE: An Event for Postgres 2025 or couldn't watch all of the sessions live, here's a playlist with the 11 talks all about Azure Database for PostgreSQL. And, if you'd like to dive even deeper, the Ultimate Guide will help you navigate the full catalog of 42 recorded talks published on YouTube. Feature Highlights Upsert and Script activity in ADF and Azure Synapse – Generally Available Power BI Entra authentication support – Generally Available New Regions: Malaysia West & Chile Central Latest Postgres minor versions: 17.5, 16.9, 15.13, 14.18 and 13.21 Cascading Read Replica – Public Preview Private Endpoint and VNet support for Fabric Mirroring - Public Preview Agentic Web with NLWeb and PostgreSQL PostgreSQL for VS Code extension enhancements Improved Maintenance Workflow for Stopped Instances Upsert and Script activity in ADF and Azure Synapse – Generally Available We’re excited to announce the general availability of Upsert method and Script activity in Azure Data Factory and Azure Synapse Analytics for Azure Database for PostgreSQL. These new capabilities bring greater flexibility and performance to your data pipelines: Upsert Method: Easily merge incoming data into existing PostgreSQL tables without writing complex logic reducing overhead and improving efficiency. Script Activity: Run custom SQL scripts as part of your workflows, enabling advanced transformations, procedural logic, and fine-grained control over data operations. Together, these features streamline ETL and ELT processes, making it easier to build scalable, declarative, and robust data integration solutions using PostgreSQL as either a source or sink. Visit our documentation guide for Upsert Method and script activity to know more. Power BI Entra authentication support – Generally Available You can now use Microsoft Entra ID authentication to connect to Azure Database for PostgreSQL from Power BI Desktop. This update simplifies access management, enhances security, and helps you support your organization’s broader Entra-based authentication strategy. To learn more, please refer to our documentation. New Regions: Malaysia West & Chile Central Azure Database for PostgreSQL has now launched in Malaysia West and Chile Central. This expanded regional presence brings lower latency, enhanced performance, and data residency support, making it easier to build fast, reliable, and compliant applications, right where your users are. This continues to be our mission to bring Azure Database for PostgreSQL closer to where you build and run your apps. For the full list of regions visit: Azure Database for PostgreSQL Regions. Latest Postgres minor versions: 17.5, 16.9, 15.13, 14.18 and 13.21 PostgreSQL latest minor versions 17.5, 16.9, 15.13, 14.18 and 13.21 are now supported by Azure Database for PostgreSQL flexible server. These minor version upgrades are automatically performed as part of the monthly planned maintenance in Azure Database for PostgreSQL. This upgrade automation ensures that your databases are always running on the most secure and optimized versions without requiring manual intervention. This release fixes two security vulnerabilities and over 40 bug fixes and improvements. To learn more, please refer PostgreSQL community announcement for more details about the release. Cascading Read Replica – Public Preview Azure Database for PostgreSQL supports cascading read replica in public preview capacity. This feature allows you to scale read-intensive workloads more effectively by creating replicas not only from the primary database but also from existing read replicas, enabling two-level replication chains. With cascading read replicas, you can: Improve performance for read-heavy applications. Distribute read traffic more efficiently. Support complex deployment topologies. Data replication is asynchronous, and each replica can serve as a source for additional replicas. This setup enhances scalability and flexibility for your PostgreSQL deployments. For more details read the cascading read replicas documentation. Private Endpoint and VNET Support for Fabric Mirroring - Public Preview Microsoft Fabric now supports mirroring for Azure Database for PostgreSQL flexible server instances deployed with Virtual Network (VNET) integration or Private Endpoints. This enhancement broadens the scope of Fabric’s real-time data replication capabilities, enabling secure and seamless analytics on transactional data, even within network-isolated environments. Previously, mirroring was only available for flexible server instances with public endpoint access. With this update, organizations can now replicate data from Azure Database for PostgreSQL hosted in secure, private networks, without compromising on data security, compliance, or performance. This is particularly valuable for enterprise customers who rely on VNETs and Private Endpoints for database connectivity from isolated networks. For more details visit fabric mirroring with private networking support blog. Agentic Web with NLWeb and PostgreSQL We’re excited to announce that NLWeb (Natural Language Web), Microsoft’s open project for natural language interfaces on websites now supports PostgreSQL. With this enhancement, developers can leverage PostgreSQL and NLWeb to transform any website into an AI-powered application or Model Context Protocol (MCP) server. This integration allows organizations to utilize a familiar, robust database as the foundation for conversational AI experiences, streamlining deployment and maximizing data security and scalability. For more details, read Agentic web with NLWeb and PostgreSQL blog. PostgreSQL for VS Code extension enhancements PostgreSQL for VS Code extension is rolling out new updates to improve your experience with this extension. We are introducing key connections, authentication, and usability improvements. Here’s what we improved: SSH connections - You can now set up SSH tunneling directly in the Advanced Connection options, making it easier to securely connect to private networks without leaving VS Code. Clearer authentication setup - A new “No Password” option eliminates guesswork when setting up connections that don’t require credentials. Entra ID fixes - Improved default username handling, token refresh, and clearer error feedback for failed connections. Array and character rendering - Unicode and PostgreSQL arrays now display more reliably and consistently. Azure Portal flow - Reuses existing connection profiles to avoid duplicates when launching from the portal. Don’t forget to update to the latest version in the Marketplace to take advantage of these enhancements and visit our GitHub to learn more about this month’s release. Improved Maintenance Workflow for Stopped Instances We’ve improved how scheduled maintenance is handled for stopped or disabled PostgreSQL servers. Maintenance is now applied only when the server is restarted - either manually or through the 7-day auto-restart rather than forcing a restart during the scheduled maintenance window. This change reduces unnecessary disruptions and gives you more control over when updates are applied. You may notice a slightly longer restart time (5–8 minutes) if maintenance is pending. For more information, refer Applying Maintenance on Stopped/Disabled Instances. Azure Postgres Learning Bytes 🎓 Set Up HA Health Status Monitoring Alerts This section will talk about setting up HA health status monitoring alerts using Azure Portal. These alerts can be used to effectively monitor the HA health states for your server. To monitor the health of your High Availability (HA) setup: Navigate to Azure portal and select your Azure Database for PostgreSQL flexible server instance. Create an Alert Rule Go to Monitoring > Alerts > Create Alert Rule Scope: Select your PostgreSQL Flexible Server Condition: Choose the signal from the drop down (CPU percentage, storage percentage etc.) Logic: Define when the alert should trigger Action Group: Specify where the alert should be sent (email, webhook, etc.) Add tags Click on “Review + Create” Verify the Alert Check the Alerts tab in Azure Monitor to confirm the alert has been triggered. For deeper insight into resource health: Go to Azure Portal > Search for Service Health > Select Resource Health. Choose Azure Database for PostgreSQL Flexible Server from the dropdown. Review the health status of your server. For more information, check out the HA Health status monitoring documentation guide. Conclusion That’s a wrap for our July 2025 feature updates! Thanks for being part of our journey to make Azure Database for PostgreSQL better with every release. We’re always working to improve, and your feedback helps us do that. 💬 Got ideas, questions, or suggestions? We’d love to hear from you: https://aka.ms/pgfeedback 📢 Want to stay on top of Azure Database for PostgreSQL updates? Follow us here for the latest announcements, feature releases, and best practices: Azure Database for PostgreSQL Blog Stay tuned for more updates in our next blog!Model Context Protocol (MCP) Server for Azure Database for MySQL
We are excited to introduce a new MCP Server for integrating your AI models with data hosted in Azure Database for MySQL. By utilizing this server, you can effortlessly connect any AI application that supports MCP to your MySQL flexible server (using either MySQL password-based authentication or Microsoft Entra authentication methods), enabling you to provide your business data as meaningful context in a standardized and secure manner.Upgrade performance, availability and security with new features in Azure Database for PostgreSQL
At Microsoft Build 2025 the Postgres on Azure team is announcing an exciting set of improvements and features for Azure Database for PostgreSQL. One area we are always focused on is the enterprise. This week we are delighted to announce improvements across the enterprise pillars of Performance, Availability and Security. In addition, we're improving Integration of Postgres workloads with services like ADF and Fabric. Here's a quick tour of the enterprise enhancements to Azure Database for PostgreSQL being announced this week. Performance and scale SSD v2 with HA support - Public Preview The public preview of zone-redundant high availability (HA) support for the Premium SSD v2 storage tier with Azure Database for PostgreSQL flexible server is now available. You can now enable High Availability with zone redundancy using Azure Premium SSD v2 when deploying flexible server, helping you achieve a Recovery Point Objective (RPO) of zero for mission-critical workloads. Premium SSD v2 offers sub-millisecond latency and outstanding performance at a low cost, making it ideal for IO-intensive, enterprise-grade workloads. With this update, you can significantly boost the price-performance of your PostgreSQL deployments on Azure and improve availability with reduced downtime during HA failover. The key benefits of SSD v2 include: Flexible disk sizing from 1 GiB to 64 TiB, with 1-GiB increment support Independent performance configuration: scale up to 80,000 IOPS and 1,200 MBps throughput without needing to provision larger disks To learn more about how to upgrade and best practices, visit: Premium SSDv2 PostgreSQL 17 Major Version Upgrade – Public Preview PostgreSQL version 17 brings a host of performance improvements, including a more efficient VACUUM process, faster sequential scans via streaming IO, and optimized query execution. Now, with the public preview of in-place major version upgrades to PostgreSQL 17 there is an easier path to v17 for your existing flexible server workloads. With this release, you can upgrade from earlier versions (14, 15, or 16) to PostgreSQL 17 without the need to migrate data or change server endpoints, simplifying the upgrade process and minimizing downtime. Azure’s in-place upgrade capability offers a native, low-disruption upgrade path directly from the Azure Portal or CLI. For upgrade steps and best practices, check out our detailed blog post. Availability Long-Term Backup (LTR) for Azure Database for PostgreSQL flexible server - Generally Available Long-term backups are essential for organizations with regulatory, compliance, and audit-driven requirements, especially in industries like finance and healthcare. Certifications such as HIPAA often mandate data retention periods up to 10 years, far exceeding the default 35-day retention limit provided by point-in-time restore (PITR) capabilities. Long-term backup for Azure Database for PostgreSQL flexible server, powered by Azure Backup is now generally available. With this release, you can now benefit from: Policy-driven, one-click enablement of long-term backups Resilient data retention across Azure Storage tiers Consumption-based pricing with no egress charges Support for restoring backups well beyond community-supported PostgreSQL versions This LTR capability uses a logical backup approach based on pg_dump and pg_restore, offering a flexible, open-source format that enhances portability and ensures your data can be restored across a variety of environments including Azure VMs, on-premises, or even other cloud providers. Learn more about long term retention: Backup and restore - Azure Database for PostgreSQL flexible server Azure Databases for PostgreSQL flexible server Resiliency Solution accelerator When it comes to ensuring business continuity, your database infrastructure is the most critical component. In addition to product documentation, it is important to have access to opinionated solution architecture, industry-proven recommended practices, and deployable infra-as-code that you can learn and customize to ensure an automated production-ready resilient infrastructure for your data. The Azure Database for PostgreSQL Resiliency Solution Accelerator is now available, providing a set of deployable architectures to ensure business continuity, minimize downtime, and protect data integrity during planned and unplanned events. In additional to architecture and recommended practices, a customizable Terraform deployment workflow is provided. Learn more: Azure Database for PostgreSQL Resiliency Solution Accelerator Security Automatic Customer Managed Key (CMK) version updates - Generally Available Azure Database for PostgreSQL flexible server data is fully encrypted, supporting both Service Managed and Customer Managed encryption keys (CMK). Automatic version updates for CMK (also known as “versionless keys”) is now generally available. This change simplifies the key lifecycle management by allowing PostgreSQL to automatically adopt new keys without needing manual updates. Combined with Azure Key Vault's auto-rotation feature this significantly reduces the management overhead of encryption key maintenance. Learn more about automatic CMK version updates. Azure confidential computing SKUs for flexible server - Public Preview Azure confidential computing enables secure sensitive and regulated data, preventing unwanted access of data in-use, by cloud providers, administrators, or external users. With the public preview of Azure confidential SKUs for Azure Database for PostgreSQL flexible server you can now select from a range of Confidential Computing VM sizes to run your PostgreSQL workloads in a hardware-based trusted execution environment (TEE). Azure confidential computing encrypts data in TEE, processing data in a verified environment, enabling you to securely process workloads while meeting compliance and regulatory demands. Learn more about confidential computing with the Azure Database for flexible server. Integration Entra Authentication for Azure Data Factory & Azure Synapse - Generally Available In an era of bring-your-own-device and cloud-enabled apps it is increasingly important for enterprises to maintain central control an identity-based security perimeter. With integrated Entra ID support, Azure Database for PostgreSQL flexible server allows you to bring your database workloads within this perimeter. But how do you securely connect to other services? Entra ID authentication is now supported in the Azure Data Factory and Azure Synapse connectors for Azure Database for PostgreSQL. This feature enables seamless, secure connectivity using Service Principal (key or certificate) and both User-Assigned and System-Assigned Managed Identities, streamlining access to your data pipelines and analytics workloads. Learn more about How to Connect from Azure Data Factory and Synapse Analytics to Azure Database for PostgreSQL. Fabric Data Factory – Upsert Method & Script Activity - Generally Available The Microsoft Fabric has become to go-to data analytics platform with services and tools for every data lifecycle state. To improve customization and fine-grained control over processing of PostgreSQL data, the Upsert Method and custom Script Activity are now generally available in Fabric Data Factory when using Azure Database for PostgreSQL as a source or sink. Upsert Method enables intelligent insert-or-update logic for PostgreSQL, making it easier to handle incremental data loads and change data capture (CDC) scenarios without complex workarounds. Script Activity allows you to embed and execute your own SQL scripts directly within pipelines—ideal for advanced transformations, procedural logic, and fine-grained control over data operations. These capabilities offer enhanced flexibility for building robust, enterprise-grade data workflows, simplifying your ETL processes. Connect to VS Code from the Azure Portal - Public Preview With the exciting announcement of a revamped VS Code PostgreSQL extension preview this week, we're adding a new connection option to the Azure Portal to connect to your flexible server with VS Code, creating a more unified and efficient developer experience. Here's why it matters: One Click Connectivity: No manual connection strings or configuration needed. Faster Onboarding: Go from provisioning a database in Azure to exploring and managing it in VS Code within seconds. Integrated Workflow: Manage infrastructure and development from a single, cohesive environment. Productivity: Connect directly from the Portal to leverage VS Code extension features like query editing, result views, and schema browsing. Where to learn more The Build 2025 announcements this week are just the latest in a compelling set of features delivered by the Azure Database for PostgreSQL team and build on our latest set of monthly feature updates (see: April 2025 Recap: Azure Database for PostgreSQL Flexible Server). Follow the Azure Database for PostgreSQL Blog where you'll see many of the latest updates from Build, including What's New with PostgreSQL @Build, and New Generative AI Features in Azure Database for PostgreSQL.
Ignite 2024: New innovations in Azure Database for MySQL
We're thrilled to unveil a suite of new Azure Database for MySQL features and innovations that are designed to empower both developers and enterprise organizations with the ability to get more out of their data with robust performance and efficiency, advanced security, and greater scalability for their applications. Whether you're looking to leverage cutting-edge innovations, accelerate the development of intelligent applications, or streamline your migration processes, these updates provide you with the tools you need to achieve your goals. Dive in to discover how these enhancements can enhance your projects and simplify your workflows!
Best practices for safely performing schema changes in Azure Database for MySQL
Azure Database for MySQL - Flexible Server is built on the open-source MySQL database engine, and the service supports MySQL 8.0 and newer versions. This means that users can take advantage of the flexibility and advanced capabilities of MySQL’s latest features while benefitting from a fully managed database service. While newer versions and features can provide a lot of value, the recent issues identified with MySQL versions 8.0+ makes it important to be aware of potential risks that can occur during certain operations, particularly if you are making online schema changes. Issues with data loss and duplicate keys with Online DDL Online Data Definition Language (DDL) operations are a powerful feature in MySQL, enabling schema changes like ALTER TABLE or OPTIMIZE TABLE with minimal impact on table availability. These operations are designed to reduce downtime by allowing concurrent reads and writes during schema modifications, making them an essential tool for managing active databases efficiently. However, a recent post on the Percona blog, Who Ate My MySQL Table Rows? highlights critical risks associated with MySQL 8.0.x versions after 8.0.27 and all versions beyond 8.4.y. Specifically, the open-source INPLACE algorithm, commonly used for online schema changes, can lead to data loss and duplicate key errors under certain conditions. These issues arise from constraints in the INPLACE algorithm, particularly during ALTER TABLE and OPTIMIZE TABLE operations, exposing vulnerabilities that compromise data integrity and system reliability. These risks are called out in the following bug reports: Bug #115511: Data loss during online ALTER operations with concurrent DML Bug #115608: Duplicate key errors caused by online ALTER operations Documented issues related to the INPLACE algorithm (used for online DDL) can cause: Data Loss: Rows may be accidentally deleted or become inaccessible. Duplicate Keys: Indexes can end up with duplicate entries, leading to data consistency issues and potential replication errors. Problems arise when INPLACE operations, such as ALTER TABLE or OPTIMIZE TABLE, run concurrently with: DML operations (INSERT, UPDATE, DELETE): Modifications to table data during the rebuild. A purge activity: Background cleanup operations for old row versions in InnoDB. These scenarios can lead to anomalies resulting from race conditions and incomplete synchronization between concurrent activities. Impact on Azure Database for MySQL - Flexible Server Customers For Azure Database for MySQL Flexible Server customers using MySQL 8.0+ and all versions after 8.4.y, this issue is particularly critical as it affects: Data Integrity: During schema changes such as ALTER TABLE or OPTIMIZE TABLE run using the INPLACE algorithm, data rows may be lost or duplicated if these operations run concurrently with a DML activity (e.g., INSERT, UPDATE, or DELETE) or background purge tasks. This can compromise the accuracy and reliability of the database, potentially leading to incorrect query results or the loss of critical business data. Replication Instability: Duplicate keys or missing rows can interrupt replication processes, which rely on a consistent data stream across the primary and replica servers. These issues can arise when there are concurrent insertions into the table during schema changes, leading to data inconsistencies between the primary and replicas. Such inconsistencies may result in replication lag, errors, or even a complete breakdown of high-availability setups, requiring manual intervention to restore synchronization. Operational Downtime: Resolving these issues often involves manually syncing data or restoring backups. These recovery efforts can be time-consuming and disruptive, leading to extended downtime for applications and potential business impact. Recommendations for safe schema changes on Azure Database for MySQL flexible servers To minimize the risks of data loss and duplicate keys while making schema changes, follow these best practices: Set old_alter_table=ON to Default to COPY Algorithm Enable the server parameter old_alter_table system variable so that ALTER TABLE operations without a specified ALGORITHM default to using the COPY algorithm instead of INPLACE. This reduces the risk for users who do not explicitly specify the ALGORITHM in their commands. Learn more on how configure server parameters in Azure Database for MySQL. Avoid using ALGORITHM=INPLACE Do not explicitly use ALGORITHM=INPLACE for ALTER TABLE commands, as it increases the risk of data loss or duplicate keys. Back up your data before schema changes Always perform a full on-demand backup of your server before executing schema changes. This precaution ensures data recoverability in case of unexpected issues. Learn more on how to take full on-demand backups for your server. Avoid Concurrent DML during schema changes Schedule schema changes like ALTER TABLE and OPTIMIZE TABLE during application maintenance windows when no concurrent writes activities occur. This minimizes race conditions and synchronization conflicts. Use External Tools for Safer Online Schema Changes Consider using external tools like pt-online-schema-change to modify table definitions without blocking concurrent changes. These tools enable you to make schema changes with minimal impact on availability and performance. Learn more about pt-online-schema-change. Disclaimer: The pt-online-schema-change tool is not managed or supported by Microsoft; use it at your discretion. Mitigation plans To address these risks, we’re actively working to integrate the necessary fixes to ensure a more robust and reliable experience for our customers. New Servers Fully Secured by End of February 2025 All new Azure Database for MySQL Flexible Server instances created after 1 st March 2025, will include the latest fixes, ensuring that schema changes are safeguarded against data loss and duplicate key risks. Rollout for Existing Servers For existing servers, we will roll out patches during upcoming maintenance windows by end of Q1 of Calendar Year 2025 We recommend monitoring your Azure portal for scheduled maintenance windows and Release notes for announcements about critical updates and patches. Priority updates available upon request If you require an urgent update outside of the scheduled maintenance windows, you can contact Azure Support. Provide the necessary server details and an appropriate maintenance window, and our team will work with you to prioritize the patching process. Note that priority patching will be available by February 2025. We recommend monitoring Release notes for announcements about critical updates and patches. Conclusion Safely managing schema changes on MySQL servers requires understanding the risks associated with online DDL operations, such as potential data loss and duplicate keys. To help safeguard data integrity and maintain server stability, implement best practices, for example enabling the COPY algorithm, using offline operations if feasible, or scheduling changes during low activity periods. Fixes are expected by the end of February 2025, and new Azure Database for MySQL flexible servers will be fully protected against these bugs. We will apply updates to existing servers during maintenance windows in Q1 2025. Following the recommendations above will help ensure that you can confidently make schema changes while preserving the reliability and performance of your server.
