SQL + AI: Get ready for a fun new experience, launching next week!
The SQL community is leveling up! We’re launching a lightweight, beginner friendly SQL + AI contest designed to spark awareness of SQL Server 2025’s new AI capabilities—from connecting to an AI model, to generating embeddings, to exploring what’s possible when natural language intelligence meets your database. Building on the momentum, each week in February unlocks a new chapter of the story - from your first steps connecting SQL to AI, to exploring embeddings, to experimenting with lightweight RAG patterns, and finally orchestrating full end-to-end workflows. This will be hands-on, guided, and fun! You don’t need to be an AI expert to participate. Each challenge builds on the last, helping you discover what’s possible when SQL’s new capabilities meet real world scenarios — all in a fun, approachable format designed to spark curiosity and get people talking. Join us for some SQL fun starting next week, February 5th! Stay tuned to this post for more details! Get ready to build, discover, and play. SQL + AI is here.
Announcing SQLCon 2026: Better Together with FabCon!
We’re thrilled to unveil SQLCon 2026, the premier Microsoft SQL Community Conference, co-located with the Microsoft Fabric Community Conference (FabCon) from March 16–20, 2026! This year, we’re bringing the best of both worlds under one roof—uniting the vibrant SQL and Fabric communities for a truly next-level experience. Whether you’re passionate about SQL Server, Azure SQL, SQL in Fabric, SQL Tools, migration and modernization, database security, or building AI-powered apps with SQL, SQLCon 2026 has you covered. Dive into 50+ breakout sessions and 4 expert-led workshops designed to help you optimize, innovate, and connect. Why are SQLCon + FabCon better together? One registration, double the value: Register for either conference and get full access to both—mix and match sessions, keynotes, and community events to fit your interests. Shared spaces, shared energy: Enjoy the same expo hall, registration desk, conference app, and community lounge. Network with peers across the data platform spectrum. Unforgettable experiences: Join us for both keynotes at the State Farm Arena and celebrate at the legendary attendee party at the Georgia Aquarium. Our goal is to reignite the SQL Community spirit—restoring the robust networks, friendships, and career-building opportunities that make this ecosystem so special. SQLCon is just the beginning of a renewed commitment to connect at conferences, user groups, online, and at regional events. Early Access Pricing Extended! Register by November 14th and save $200 with code SQLCMTY200. Register Now! Want to share your expertise? The Call for Content is open until November 20th for both conferences! Let’s build the future of data—together. See you at SQLCon + FabCon!SQL Server Management Studio (SSMS) 21 is now generally available (GA)
The SQL Tools team is thrilled to announce the general availability of SQL Server Management Studio (SSMS) 21. SSMS 21 GA brings a modern installation and update experience through the Visual Studio installer, 64-bit support, Git integration, and initial dark theme support.SQL Server 2025 is Now Generally Available
Today at Ignite, we announce the general availability of SQL Server 2025. This marks the latest milestone in the more than 30-year history of SQL Server. It is also a key part of our commitment to the one consistent SQL promise, delivering consistent experience across on-premises, cloud, and SaaS environments, with one engine and one unified platform. Built on SQL Server’s foundation of best-in-class security, performance and availability, SQL Server 2025 is the AI-ready enterprise database and it redefines what's possible for enterprise data. With built-in AI and developer-first enhancements, SQL Server 2025 empowers customers to accelerate AI innovation using the data they already have, securely and at scale, all within SQL Server using the familiar T-SQL language. SQL Server 2025 is designed to meet customers where they are, whether on-premises, in the cloud, or in hybrid environments, helping you build intelligent, secure, scalable, and consistent solutions that drive real business outcomes. SQL Server 2025 is experiencing significant momentum, as evidenced by 10,000 organizations participating in the public preview and 100,000 active SQL Server 2025 databases. Leading customers like Mediterranean Shipping Company (MSC), Infios, and Buhler are already advancing with SQL Server 2025, supported by a robust ecosystem of technology partners including AMD, Canonical, HPE, Lenovo, NVIDIA, Pure Storage and Red Hat. Key Innovations in SQL Server 2025 AI built-in AI is now integrated directly into the SQL Server engine, enabling advanced semantic search for deeper insights and natural language experiences across enterprise data. Model management is built into T-SQL, supporting seamless integration with Microsoft Foundry, Azure OpenAI Service, OpenAI, Ollama, and more—deployable securely anywhere, from on premises to the cloud. Developers can easily switch between models without changing code, and essential AI building blocks like vector embedding, text chunking, and DiskANN indexing are natively supported. Integration with frameworks such as LangChain and Semantic Kernel accelerates AI-powered app development. At Ivanti, our mission is to elevate human potential by managing, protecting, and automating technology to drive continuous innovation. SQL Server 2025 plays a crucial role in helping us achieve this goal. By harnessing the advanced capabilities of SQL Server 2025 and Azure OpenAI, we are building intelligent, agentic tools that empower customers to access knowledge and resolve incidents faster. Sirjad Parakkat, Vice President, AI Engineering | Ivanti Made for developers This release is the most significant for SQL developers in a decade, streamlining development and boosting productivity. Native JSON support, REST APIs,RegEx and Fuzzy string match enable richer data enrichment and validation. Change event streaming allows real-time, event-driven applications by streaming changes directly from transaction to Azure Event Hubs, reducing resource overhead compared to CDC. SQL Tooling SQL Server 2025 delivers major updates across the data platform. SQL Server Management Studio (SSMS 22) is now generally available, offering official support for SQL Server 2025, enhanced AI assistance, and ARM64 support. SSMS 22 also includes AI assistance when you install the GitHub Copilot workload, which leverages the same GitHub subscription you use with GitHub Copilot in Visual Studio or VS Code. The Microsoft Python Driver for SQL Server (mssql-python) is generally available, providing a modern, high-performance connector with Entra ID authentication. "SQL Server 2025 offers two major functionalities which are very important to us and will bring SQL Server into the future – native API calls and RAG. In the past we’ve had to use custom assemblies for making API calls, which can be a huge problem when you have to make hundreds of thousands of API calls and the remote systems are slow to respond, creating large queues and high CPU load in SQL. With RAG and vector search, we can now implement countless AI possibilities, making data searchable in ways previously impossible.” Alex Ivanov, CTO, eDynamix Best-in-class security, performance, and availability SQL Server 2025 builds on its foundation as the most secure database in the last decade, introducing modern identity and encryption practices, including Microsoft Entra managed identities for improved credential management. Optimized locking reduces lock memory consumption, minimizes blocking, and boosts concurrency. Tempdb space resource governance improves server reliability. Optional parameter plan optimization makes query performance more stable. SQL Server 2025 continues to strengthen its mission-critical capabilities with enhancements to Always On availability groups (AGs) and disaster recovery options. The focus is on faster failover, improved diagnostics, and hybrid flexibility. Preliminary benchmarks show SQL Server 2025 running on AMD EPYC processors with HPE hardware delivers measurable gains in performance and value. For performance, the 10TB workload sets a new record for SQL Server. In price-performance, SQL Server 2025 achieves a 4% improvement in the 3TB category compared to previous results. “At Infios, we are very excited about several new features in SQL Server 2025 and the vast amount of opportunities for performance improvements. We are most excited about the optimized locking feature and how that can drastically help reduce locking across our customers and all their unique workloads. Optional Parameter Plan Optimization (OPPO) could also be huge for us with SQL Server being able to reduce parameter sniffing issues. Persisted statistics on secondary replicas will also be beneficial for the rare occurrence that we have a failover event. While we’ve been pleased with all the improvements to tempdb in previous versions, resource governance to prevent runaway queries and consuming large amounts of disk space in SQL 2025 is a big improvement for us. ” Tim Radney, SaaS Operations Manager, Infios Cloud agility through Azure and Fabric SQL Server 2025 enhances cloud agility with support for database mirroring in Fabric, enabling near real-time analytics with zero-ETL and offloading analytical workloads. Azure Arc integration continues to provide unified management, security, and governance for SQL estates across on-premises and cloud environments, empowering organizations to scale and modernize with confidence. “With Fabric Mirroring in SQL Server 2025, ExponentHR can effortlessly mirror numerous datasets to fabric, enabling near real-time analytics. This technology has alleviated the need for expensive and complex ETL operations and enables more productivity for our customers. Thanks to SQL Server 2025’s built-in cloud connectivity, we can directly process large amounts of data efficiently and overcome traditional bottlenecks.” -- Brent Carlson, IT Manager, ExponentHR SQL Server 2025 on Linux SQL Server 2025 on Linux introduces several important enhancements. Security is strengthened with TLS 1.3 support, custom password policies, and signed container images. Platform support expands to include RHEL 10 and Ubuntu 24.04, while performance is improved through tmpfs support for tempdb and container-based deployments. Advanced analytics are enabled with generic ODBC data source support via PolyBase. Developer experience is streamlined with Visual Studio Code integration for local container deployment using the mssql extension and validated deployment patterns in partnership with Red Hat, supporting modern workloads and AI scenarios across hybrid environments. "The work we’re doing with Microsoft to optimize SQL Server on Red Hat Enterprise Linux is a powerful testament to the strength of our collaboration. With the new features in SQL Server, including support for Red Hat Enterprise Linux 10 and enabling streamlined deployment via Red Hat Ansible Automation Platform, we are making it easier than ever for customers to deploy and manage this critical workload across the hybrid cloud. This collaboration extends beyond just enabling core performance to deliver innovative, validated patterns, such as leveraging Red Hat Enterprise Linux AI with SQL Server for retrieval-augmented generation (RAG) and generative AI scenarios, and providing a more consistent experience for customers, whether they are deploying via the Azure Marketplace or on-premises. Our mutual goal is to minimize complexity, increase confidence and help enterprises harness the full potential of their data and AI investments on a trusted, open foundation." - Gunner Hellekson, Vice President and General Manager, Red Hat Enterprise Linux, Red Hat SQL Server 2025 on Azure Virtual Machines Run SQL Server 2025—any edition, Standard, Enterprise, Enterprise Developer, or the new Standard Developer Edition—on Azure Virtual Machines, using optimized VM families like Mbdsv3, Ebdsv5/6, and FXmdsv2 for high performance. Pair with Premium SSD v2 or Ultra Disk storage to achieve fast throughput, low latency, and excellent scalability. Deploy quickly from the Azure portal with features including configurable settings, flexible licensing, storage setup for data, logs, and tempdb, automated patching, and Best Practice Assessment (BPA). Get started today to leverage SQL Server 2025 and Azure’s high performance and flexibility. Preview Features & Flexibility In SQL Server 2025, customers can explore new database features using an opt-in mechanism through database-scoped configurations. Certain features, such as vector indexes, are introduced this way, allowing customers to try them in preview even while SQL Server is generally available. These features will become fully available in a future SQL Server 2025 update, at which point the database-scoped configuration will no longer be required. Our goal is to make preview features generally available within approximately 12 months, guided by customer feedback and our commitment to delivering high-quality experiences. Learn more. Product Changes SQL Server 2025 brings important changes to the product lineup. Standard edition changes: Resource limits have increased to support up to 32 cores and 256 GB of memory. Resource governor is now available in Standard edition. The newly launched Standard Developer edition offers full feature parity with the Standard edition, enabling development and testing that mirrors production environment capabilities. Power BI Report Server entitlement is now included for all editions except the Express edition, adding value for customers. Express edition changes: The maximum database size is now increased to 50 GB per database. The Express Advanced mode has been consolidated into a single, unified SQL Express edition, featuring all feature capabilities that were available in Express Advanced. Discontinuing Web edition in SQL Server 2025 release: SQL Server 2022 is the final version of the Web edition, with SQL Server 2022 Web edition remaining supported until January 2033 in line with Microsoft’s fixed lifecycle policy. If you've been using the Web edition for cost-effective web applications, now is a great time to consider migrating to Azure SQL. Azure SQL offers an affordable, scalable solution that is well-suited for modern web workloads. For multi-tenant apps, Azure SQL Database elastic pools provide flexible pricing and easy management—making the move to Azure SQL a smart choice for future growth. If you remain on-premises or use Azure SQL Virtual Machines, upgrade to the Standard edition. Modern Reporting and Analytics On-premises SQL Server Reporting Service (SSRS) consolidated into Power BI Report Server is now the default reporting solution, unifying paginated and interactive reports for all paid SQL Server licenses. Learn more. SQL Server Analysis Services 2025 introduces major performance enhancements, including improved MDX query efficiency, parallel DirectQuery execution, and visual DAX calculations for simplified modeling. It also adds new DAX functions, client library updates, and deprecates PowerPivot for SharePoint, while discontinuing HTTP access via msmdpump.dll by default. Learn more. SQL Server Integration Services (SSIS) now introduces support for the Microsoft SqlClient Data Provider in ADO.NET connection manager, enhancing connectivity and modernizing data integration workflows. Learn more. Partner Momentum Partners such as AMD, Intel, and HPE are collaborating on advanced performance and high availability solutions, including benchmark testing on AMD EPYC and Intel Xeon processors, with HPE achieving world record results for performance and price/performance. NVIDIA is working with SQL Server 2025 to enable streamlined deployment of GPU-optimized AI models using built-in REST APIs, supporting flexible AI workloads across environments. Pure Storage is delivering high availability and fast backup solutions through deep integration with SQL Server 2025, including metadata-aware snapshots and automation for simplified operations. Additionally, Microsoft works closely with partners like Canonical and Red Hat to ensure SQL Server is integrated seamlessly and operates effectively within the Linux ecosystem, providing customers with robust and reliable database solutions across a broader range of environments. Get Started Today SQL Server 2025 reaffirms Microsoft’s commitment to innovation, performance, and developer empowerment. We thank our customers, partners, and community for your ongoing support and feedback. We look forward to seeing what you build next with the AI-ready enterprise database. Download SQL Server 2025 today One consistent SQL: the launchpad from legacy to innovation Learn more through documentation and our Mechanics video Master SQL Server 2025 with a full learning path and claim your badge Get started with Azure SQL Share your feedback at SQL Community
SQL Server 2025: introducing tempdb space resource governance
An old problem Since the early days of SQL Server, DBAs had to contend with a common problem – running out of space in the tempdb database. It has always struck me as odd that all I need to cause an outage on an SQL Server instance is access to the server where I can create a temp table that fills up tempdb, and there is no permission to stop me. - Erland Sommarskog (website), an independent SQL Server consultant and a Data Platform MVP Because tempdb is used for a multitude of purposes, the problem can occur without any explicit user action such as creating a temporary table. For example, executing a reporting query that spills data to tempdb and fills it up can cause an outage for all workloads using that SQL Server instance. Over the years, many DBAs developed custom solutions that monitor tempdb space and take action, for example kill sessions that consume a large amount of tempdb space. But that comes with extra effort and complexity. I have spent more hours in my career than I can count building solutions to manage TempDB space. Even with immense time and effort, there were still quirks and caveats that came up that created challenges - especially in multi-tenant environments with lots of databases and the noisy-neighbor problem. - Edward Pollack (LinkedIn), Data Architect at Transfinder and a Data Platform MVP A new solution in the SQL Server engine SQL Server 2025 brings a new solution for this old problem, built directly into the database engine. Starting with the CTP 2.0 release, you can use resource governor, a feature available since SQL Server 2008, to enforce limits on tempdb space consumption. We rely on Resource Governor to isolate workloads on our SQL Server instances by controlling CPU and memory usage. It helps us ensure that the core of our trading systems remains stable and runs with predictable performance, even when other parts of the systems share the same servers. - Ola Hallengren (website), Chief Data Platforms Engineer at Saxo Bank and a Data Platform MVP Similarly, if you have multiple workloads running on your server, each workload can have its own tempdb limit, lower than the maximum available tempdb space. This way, even if one workload hits its limit, other workloads continue running. Here's an example that limits the total tempdb space consumption by queries in the default workload group to 17 GB, using just two T-SQL statements: ALTER WORKLOAD GROUP [default] WITH (GROUP_MAX_TEMPDB_DATA_MB = 17408); ALTER RESOURCE GOVERNOR RECONFIGURE; The default group is used for all queries that aren’t classified into another workload group. You can create workload groups for specific applications, users, etc. and set limits for each group. When a query attempts to increase tempdb space consumption beyond the workload group limit, it is aborted with error 1138, severity 17, Could not allocate a new page for database 'tempdb' because that would exceed the limit set for workload group 'workload-group-name'. All other queries on the server continue to execute. Setting the limits You might be asking, “How do I know the right limits for the different workloads on my servers?” No need to guess. Tempdb space usage is tracked for each workload group at all times and reported in the sys.dm_resource_governor_workload_groups DMV. Usage is tracked even if no limits are set for the workload groups. You can establish representative usage patterns for each workload over time, then set the right limits. You can reconfigure the limits over time if workload patterns change. For example, the following query lets you see the current tempdb space usage, peak usage, and the number of times queries were aborted because they would otherwise exceed the limit per workload group: SELECT group_id, name, tempdb_data_space_kb, peak_tempdb_data_space_kb, total_tempdb_data_limit_violation_count FROM sys.dm_resource_governor_workload_groups; Peak usage and the number of query aborts (limit violations) are tracked since server restart. You can reset these and other resource governor statistics to restart tracking at any time and without restarting the server by executing ALTER RESOURCE GOVERNOR RESET STATISTICS; What about the transaction log? The limits you set for each workload group apply to space in the tempdb data files. But what about the tempdb transaction log? Couldn’t a large transaction fill up the log and cause an outage? This is where another feature in SQL Server 2025 comes in. You can now enable accelerated database recovery (ADR) in tempdb to get the benefit of aggressive log truncation, and drastically reduce the possibility of running out of log space in tempdb. For more information, see ADR improvements in SQL Server 2025. Learn more For more information about tempdb space resource governance, including examples, best practices, and the details of how it works, see Tempdb space resource governance in documentation. If you haven’t used resource governor in SQL Server before, here’s a good starting point: Tutorial: Resource governor configuration examples and best practices. Conclusion SQL Server 2025 brings a new, built-in solution for the age-old problem of tempdb space management. You can now use resource governor to set limits on tempdb usage and avoid server-wide outages because tempdb ran out of space. We are looking forward to your feedback on this and other SQL Server features during the public preview of SQL Server 2025 and beyond. You can leave comments on this blog post, email us at sql-rg-feedback@microsoft.com, or leave feedback at https://aka.ms/sqlfeedback.Writing a great session abstract for FabCon & SQLCon
Important Dates FabCon/SQLCon Europe in Barcelona, runs 2026 September 28 - Oct 1, 2026 Workshop Call for Content open Feb 17, 2026 to March 23, 2026 Breakout Session Call for Content open Feb 17, 2026 to April 17, 2026 When submitting a session to a conference, consider the following: Title: The title should answer the attendee's question what's in it for me? Why should I attend this session? Is it going to make me better at my job? Will it save my company money? Will it make my reports more organized or my database faster, more secure or modern? The title needs to make sense; it needs to inform. It doesn't need to be funny or contain a dad joke. It CAN, but that's secondary. It shouldn't just be the name of a product or even "Learn [product name]" because you can't teach me everything about it in 60 minutes or less. Abstract: The abstract should contain 3 things: It should define the problem you're trying to solve. It should introduce the solution. It should briefly describe what they'll learn about the solution. In the time allotted. The problem can be that the attendee doesn’t know how to create great visuals, performance tune, connect to Lakehouse, etc. If so, consider titles like “Creating Great Visuals Using...”, “Cutting Costs by Optimizing Your...”, or “Understanding Governance in…” The abstract can introduce a new feature or concept. If so, then the problem is "there's a new thing that you don't know about yet." The solution is "this feature does X, Y & Z." Then tell them that they'll learn everything about X or a little bit about X, Y & Z. If you include an acronym, make sure you spell it out first. Not everyone is going to know what it means, and you don't want only a room full of attendees that already know everything. Avoid using many buzz words in you title or abstract. Drop it into Copilot for a final check and use prompts to help improve your work. Use "make it more precise" if it's over the character count. Tey "make it more professional" if you think it's more casual than you intended. Final check: Before you hit submit, run your abstract by a friend. Does it make sense to the technical and/or non-technical? Do the grammar & spelling check out? With allowances for English not being your 1st language, the abstract should show that you can effectively communicate the topic to an audience. Does the level assigned match the abstract? Is it in the right track? Most calls for content provide definitions on what's a good fit for content in each topic. You can find the topic definitions for FabCon/SQLCon Europe here. Can you do ALL THIS in 60 minutes? Does it fit within the character count? Lastly, a few "don'ts" Don't include your name in the abstract if you know the review is done blind. Don't add it to every category or track. Be mindful. Don't email organizers to say you've submitted a session. They know. Don't demand feedback the very day you're declined. Well, never demand it, but waiting a week to politely ask never hurts. Respect the decision if they aren’t able to offer you feedback. Remember that 800 people might be asking the same question. Don't be entitled. No one *stole* your spot. It was never yours to begin with. Don't use AI to write your entire abstract. Reviewers typically know when it's not written by a human or there are tools that help them check. If you can't convey a concept on your own in 400 characters, how can we trust that you can speak on the concept for a full hour?Announcing Public Preview of DiskANN in SQL Server 2025
We are excited to announce the public preview of DiskANN in SQL Server 2025, a significant advancement in our AI capabilities. This release comes with full vector support, enabling the storing and querying of embeddings, which are essential for modern AI applications.SQL Server 2025: introducing optimized Halloween protection
Executive summary Optimized Halloween protection, available in the public preview of SQL Server 2025 starting with the CTP 2.0 release, reduces tempdb space consumption and improves query performance by redesigning the way the database engine solves the Halloween problem. An example in the appendix shows CPU and elapsed time of a query reduced by about 50% while eliminating all tempdb space consumption. Update 2025-09-02 During public preview of SQL Server 2025, we identified a potential data integrity issue that might occur if optimized Halloween protection is enabled. While the probability of encountering this issue is low, we take data integrity seriously. Therefore, we temporarily removed optimized Halloween protection from SQL Server 2025, starting with the RC 0 release. The fix for this issue is in progress. In the coming months, we plan to make optimized Halloween protection available in Azure SQL Database and Azure SQL Managed Instance with the always-up-to-date update policy. Enabling optimized Halloween protection in a future SQL Server 2025 update is under consideration as well. The Halloween problem The Halloween problem, named so because it was discovered on Halloween in 1976, occurs when a data modification language (DML) statement changes data in such a way that the same statement unexpectedly processes the same row more than once. Traditionally, the SQL Server database engine protects DML statements from the Halloween problem by introducing a spool operator in the query plan, or by taking advantage of another blocking operator already present in the plan, such as a sort or a hash match. If a spool operator is used, it creates a temporary copy of the data to be modified before any modifications are made to the data in the table. While the protection spool avoids the Halloween problem, it comes with downsides: The spool requires extra resources: space in tempdb, disk I/O, memory, and CPU. Statement processing by the downstream query operators is blocked until the data is fully written into the spool. The spool adds query plan complexity that can cause the query optimizer to generate a less optimal plan. Optimized Halloween protection removes these downsides by making the spool operator unnecessary. How it works When accelerated database recovery (ADR) is enabled, each statement in a transaction obtains a unique statement identifier, known as nest ID. As each row is modified by a DML statement, it is stamped with the nest ID of the statement. This is required to provide the ACID transaction semantics with ADR. During DML statement processing, when the storage engine reads the data, it skips any row that has the same nest ID as the current DML statement. This means that the query processor doesn't see the rows already processed by the statement, therefore avoiding the Halloween problem. How to use optimized Halloween protection To enable optimized Halloween protection for a database, the following prerequisites are required: ADR must be enabled on the database. The database must use compatibility level 170. The OPTIMIZED_HALLOWEEN_PROTECTION database-scoped configuration must be enabled. The OPTIMIZED_HALLOWEEN_PROTECTION database-scoped configuration is enabled by default. This means that when you enable ADR for a database using compatibility level 170, it will use optimized Halloween protection. You can ensure that a database uses optimized Halloween protection by executing the following statements: ALTER DATABASE [<database-name-placeholder>] SET ACCELERATED_DATABASE_RECOVERY = ON WITH ROLLBACK IMMEDIATE; ALTER DATABASE [<database-name-placeholder>] SET COMPATIBILITY_LEVEL = 170; ALTER DATABASE SCOPED CONFIGURATION SET OPTIMIZED_HALLOWEEN_PROTECTION = ON; You can also enable and disable optimized Halloween protection at the query level by using the ENABLE_OPTIMIZED_HALLOWEEN_PROTECTION and DISABLE_OPTIMIZED_HALLOWEEN_PROTECTION query hints, either directly in the query, or via Query Store hints. These hints work under any compatibility level and take precedence over the OPTIMIZED_HALLOWEEN_PROTECTION database-scoped configuration. When optimized Halloween protection is used for an operator in the query plan, the OptimizedHalloweenProtectionUsed property of the operator in the XML query plan is set to True. For more details, see optimized Halloween protection in documentation. Conclusion Optimized Halloween protection is another Intelligent Query Processing feature that improves query performance and reduces resource consumption when you upgrade to SQL Server 2025, without having to make any changes to your query workloads. We are looking forward to your feedback about this and other features during the public preview of SQL Server 2025 and beyond. You can leave comments on this blog post, email us at intelligentqp@microsoft.com, or leave feedback at https://aka.ms/sqlfeedback. Appendix The following script shows how optimized Halloween protection removes the protection spool in the query plan, and reduces tempdb usage, CPU time, and duration when enabled. /* Requires the WideWorldImporters sample database. SQL Server backup: https://github.com/Microsoft/sql-server-samples/releases/download/wide-world-importers-v1.0/WideWorldImporters-Full.bak Bacpac: https://github.com/Microsoft/sql-server-samples/releases/download/wide-world-importers-v1.0/WideWorldImporters-Standard.bacpac */ /* Ensure that optimized Halloween protection prerequisites are in place */ ALTER DATABASE WideWorldImporters SET ACCELERATED_DATABASE_RECOVERY = ON WITH ROLLBACK IMMEDIATE; ALTER DATABASE WideWorldImporters SET COMPATIBILITY_LEVEL = 170; ALTER DATABASE SCOPED CONFIGURATION SET OPTIMIZED_HALLOWEEN_PROTECTION = ON; GO /* Validate configuration */ SELECT d.compatibility_level, d.is_accelerated_database_recovery_on, dsc.name, dsc.value FROM sys.database_scoped_configurations AS dsc CROSS JOIN sys.databases AS d WHERE dsc.name = 'OPTIMIZED_HALLOWEEN_PROTECTION' AND d.name = DB_NAME(); GO /* Create the test table and add data */ DROP TABLE IF EXISTS dbo.OptimizedHPDemo; BEGIN TRANSACTION; SELECT * INTO dbo.OptimizedHPDemo FROM Sales.Invoices ALTER TABLE dbo.OptimizedHPDemo ADD CONSTRAINT PK_OptimizedHPDemo PRIMARY KEY CLUSTERED (InvoiceID) ON USERDATA; COMMIT; GO /* Ensure that Query Store is enabled and is capturing all queries */ ALTER DATABASE WideWorldImporters SET QUERY_STORE = ON (OPERATION_MODE = READ_WRITE, QUERY_CAPTURE_MODE = ALL); /* Empty Query Store to start with a clean slate */ ALTER DATABASE WideWorldImporters SET QUERY_STORE CLEAR; GO /* Disable optimized Halloween protection as the baseline */ ALTER DATABASE SCOPED CONFIGURATION SET OPTIMIZED_HALLOWEEN_PROTECTION = OFF; GO /* Insert data selecting from the same table. This requires Halloween protection so that the same row cannot be selected and inserted repeatedly. */ BEGIN TRANSACTION; INSERT INTO dbo.OptimizedHPDemo ( InvoiceID, CustomerID, BillToCustomerID, OrderID, DeliveryMethodID, ContactPersonID, AccountsPersonID, SalespersonPersonID, PackedByPersonID, InvoiceDate, CustomerPurchaseOrderNumber, IsCreditNote, CreditNoteReason, Comments, DeliveryInstructions, InternalComments, TotalDryItems, TotalChillerItems, DeliveryRun, RunPosition, ReturnedDeliveryData, ConfirmedDeliveryTime, ConfirmedReceivedBy, LastEditedBy, LastEditedWhen ) SELECT InvoiceID + 1000000 AS InvoiceID, CustomerID, BillToCustomerID, OrderID, DeliveryMethodID, ContactPersonID, AccountsPersonID, SalespersonPersonID, PackedByPersonID, InvoiceDate, CustomerPurchaseOrderNumber, IsCreditNote, CreditNoteReason, Comments, DeliveryInstructions, InternalComments, TotalDryItems, TotalChillerItems, DeliveryRun, RunPosition, ReturnedDeliveryData, ConfirmedDeliveryTime, ConfirmedReceivedBy, LastEditedBy, LastEditedWhen FROM dbo.OptimizedHPDemo; ROLLBACK; GO /* Enable optimized Halloween protection. Execute the following statement in its own batch. */ ALTER DATABASE SCOPED CONFIGURATION SET OPTIMIZED_HALLOWEEN_PROTECTION = ON; GO /* Execute the same query again */ BEGIN TRANSACTION; INSERT INTO dbo.OptimizedHPDemo ( InvoiceID, CustomerID, BillToCustomerID, OrderID, DeliveryMethodID, ContactPersonID, AccountsPersonID, SalespersonPersonID, PackedByPersonID, InvoiceDate, CustomerPurchaseOrderNumber, IsCreditNote, CreditNoteReason, Comments, DeliveryInstructions, InternalComments, TotalDryItems, TotalChillerItems, DeliveryRun, RunPosition, ReturnedDeliveryData, ConfirmedDeliveryTime, ConfirmedReceivedBy, LastEditedBy, LastEditedWhen ) SELECT InvoiceID + 1000000 AS InvoiceID, CustomerID, BillToCustomerID, OrderID, DeliveryMethodID, ContactPersonID, AccountsPersonID, SalespersonPersonID, PackedByPersonID, InvoiceDate, CustomerPurchaseOrderNumber, IsCreditNote, CreditNoteReason, Comments, DeliveryInstructions, InternalComments, TotalDryItems, TotalChillerItems, DeliveryRun, RunPosition, ReturnedDeliveryData, ConfirmedDeliveryTime, ConfirmedReceivedBy, LastEditedBy, LastEditedWhen FROM dbo.OptimizedHPDemo; ROLLBACK; GO /* Examine query runtime statistics and plans for the two executions of the same query. */ SELECT q.query_id, q.query_hash, qt.query_sql_text, p.plan_id, rs.count_executions, rs.avg_tempdb_space_used * 8 / 1024. AS tempdb_space_mb, FORMAT(rs.avg_cpu_time / 1000., 'N0') AS avg_cpu_time_ms, FORMAT(rs.avg_duration / 1000., 'N0') AS avg_duration_ms, TRY_CAST(p.query_plan AS xml) AS xml_query_plan FROM sys.query_store_runtime_stats AS rs INNER JOIN sys.query_store_plan AS p ON rs.plan_id = p.plan_id INNER JOIN sys.query_store_query AS q ON p.query_id = q.query_id INNER JOIN sys.query_store_query_text AS qt ON q.query_text_id = qt.query_text_id WHERE q.query_hash = 0xC6ADB023512BBCCC; /* For the second execution with optimized Halloween protection: 1. tempdb space usage is zero 2. CPU time and duration are reduced by about 50% 3. The Clustered Index Insert operator in the query plan has the OptimizedHalloweenProtection property set to True */
