We are always in search of ways to optimize query performance. At the heart of achieving these goals within SQL Server is the Query Optimizer, a sophisticated component of the SQL Server Database Engine. Its primary role is to evaluate various potential execution plans for a given query and select the most efficient path forward. This process is necessary for minimizing resource consumption and execution time, while enhancing the overall performance and scalability of database operations.
Category: Internals
SQL Server 2022 Enhancement for Accelerated Database Recovery
With its debut in SQL Server 2019, Accelerated Database Recovery (ADR) represents a paradigm shift in database recovery and performance enhancement. The primary objective of ADR is to drastically cut down the time databases require to recover from crashes, failures, or restarts. This is particularly important in environments where long-running transactions are common, ensuring that databases remain available and performant, even in the face of unexpected disruptions.
Optimizing SQL Server Performance with SQL Plan Guides
In SQL Server performance tuning, the inability to directly modify query text—often due to restrictions in application code or the use of legacy SQL Server versions that lack modern features like Query Store—poses a significant challenge. However, SQL Plan Guides offer a powerful alternative, providing a means to influence query execution plans and optimize performance without altering the queries themselves. This post delves into the concept of SQL Plan Guides, illustrating their utility and guiding through their creation and application.
Navigating Asynchronous Statistics Updates in SQL Server 2022
Keeping database statistics updated is crucial for the smooth functioning of your queries. The database engine is pretty smart; it automatically refreshes these statistics to stay in sync with changes in your data. This is key for the query optimizer, the brain behind the scenes, to churn out the most efficient plans for your queries. While up-to-date statistics often improve query plan quality, the extra time added to some query executions due to statistics update may be undesirable, particularly in transactional workloads with short queries, where updating statistics may take longer than query execution itself. For this reason, the SQL Server database engine also supports an option to update statistics asynchronously.
Understanding the Intricacies of SQL Server Virtual Log Files
We as SQL Server DBAs often overlook the importance of the transaction log. It plays a pivotal role in ensuring data integrity and recoverability. To manage this effectively, SQL Server employs a system of segmentation known as Virtual Log Files, or VLFs. The intricacies of VLFs and their management are fundamental to the seamless performance of SQL Server databases.
Mastering SQL Server Extended Events for Proactive Database Troubleshooting
SQL Server Extended Events (XE) are an essential tool for modern database professionals, offering a lightweight, efficient solution for monitoring and diagnosing SQL Server. Outperforming older methods like SQL Trace, Extended Events provide a detailed view of database operations with minimal impact on performance. They are integral for identifying, analyzing, and resolving complex database performance issues and are built directly into the SQL Server engine for maximum scalability and precision.
The Power of Snapshots: Exploring Copy-On-Write in SQL Server
“Copy-On-Write” (COW) is a resource management technique used in computer programming and operating systems. Its application in SQL Server, particularly in relation to snapshot technologies, is a fundamental concept behind the functioning of database snapshots and certain types of backups. Let’s delve into the detailed workings of Copy-On-Write in the context of SQL Server:
In-Memory OLTP in SQL Server: Leveraging In-Memory Tables for Performance
In the relentless pursuit of performance, database administrators and developers continually seek strategies to make applications faster and more efficient. SQL Server’s In-Memory Online Transaction Processing (In-Memory OLTP) feature is a significant stride in this quest. This blog post will dive into the world of In-Memory OLTP, exploring what it is, its benefits, how to get started, best practices, and conclude with some final thoughts.
Balancing Workloads in SQL Server with Resource Governor
Today’s database landscape requires strategies for ensuring optimal performance and resource allocation for your workloads. SQL Server’s Resource Governor is a feature that often flies under the radar but can be essential for fine-tuning the performance of your SQL Server environment. This blog post aims to demystify the Resource Governor, explaining its functionality, utility, and walking you through a practical example of setting it up for different user groups.
A Faster Future: SQL Server 2022’s Parallel Buffer Scan
The new parallel buffer scan feature in SQL Server 2022 improves the performance of Buffer Pool scan operations on large-memory machines by utilizing multiple CPU cores. Customers running SQL Server on large-memory machines (e.g. TBs of memory) can see up to 4 ~ 20 times faster executions on some scenarios which has been slow due to Buffer Pool scan. Those scenarios include creating a new database, backup/restore operations, AlwaysOn failover, file drop, and DBCC check operations. Internal operations (e.g. checkpoint) that requires Buffer Pool scan will also get the benefits. The parallel scan feature also improves the Buffer Pool scan performance of small databases residing on large-memory machines.