In multi-user database environments, ensuring the integrity and consistency of data is essential. One common challenge is preventing multiple instances of the same stored procedure from executing at the same time, which can lead to data conflicts, race conditions, and unpredictable results. To address this, SQL Server provides a powerful tool called sp_getapplock. This post explains what sp_getapplock is, what you are actually locking when you use it, how to implement it to prevent concurrent executions of a stored procedure, and the difference between transaction-level and session-level locks.
Category: Internals
Understanding Worker Threads vs. CPU Utilization in SQL Server
When managing SQL Server performance, it’s important to understand the relationship—and the distinction—between worker threads and CPU utilization. These are two separate metrics that can behave independently. For instance, you might experience high CPU utilization while still having available worker threads, or you could have all worker threads occupied even when CPU utilization is low. This post takes a look at SQL Server worker threads and CPU utilization.
Determining When to Optimize SQL Server Workloads Versus Upgrading Hardware
When your SQL Server isn’t performing as expected, it’s tempting to think that upgrading hardware is the quick fix. More CPUs, extra memory, faster disks—they all sound like solutions that should solve the problem. But before you start investing in new equipment, it’s worth taking a step back to see if optimization can address the issues.
SSISDB Catalog and Delegation in Double-Hop Scenarios
Managing SQL Server Integration Services (SSIS) in complex, multi-server environments can present challenges, especially when it comes to credential delegation across multiple servers—a situation often referred to as the “double-hop” problem. In this post, we’ll explore how the SSISDB catalog handles delegation, the default behavior, and how to configure delegation to ensure your SSIS packages run smoothly across different servers.
Diagnosing and Resolving Last Page Insert Contention in SQL Server
In high-concurrency environments, SQL Server databases may experience performance bottlenecks due to contention issues. One common issue is Last Page Insert Contention, which occurs when multiple sessions attempt to insert records into the last page of an index simultaneously. This contention can lead to significant wait times and reduced performance, particularly in tables with ever-increasing key columns. We will look at page insert contention and give recommendations for improvement.
Testing Always Encrypted with Parameterized Queries in SQL Server
It’s more important than ever to be vigilant in protecting and securing our data. Always Encrypted is a feature in SQL Server designed to protect sensitive data, such as Social Security numbers or credit card information. In this guide, we’ll focus on testing Always Encrypted using parameterized queries to ensure data remains secure during common operations like searching, inserting, and updating.
Avoiding Recompiles in Dynamic SQL: Best Practices for SQL Server
Dynamic SQL is a powerful feature in SQL Server that allows you to build and execute SQL statements on the fly. It’s especially useful when you need flexibility in your queries based on varying conditions. However, a common issue with dynamic SQL is that it can lead to frequent recompilations of execution plans, which can hurt performance. In this post, I’ll explain why this happens, how you can avoid unnecessary recompiles, and provide scripts you can use to test these concepts yourself.
Understanding the Timeline of Query Optimization Improvements in SQL Server 2022
Intelligent Query Processing (IQP) is a suite of advanced features introduced in SQL Server 2017 and enhanced in subsequent versions, including SQL Server 2022. By upgrading to SQL Server 2022 and setting your database compatibility level to 160, you enable capabilities that dynamically optimize query performance. Understanding when these performance improvements take effect can help database administrators and developers plan and manage their optimization strategies effectively. The journey toward maximum performance improvement is gradual and influenced by factors such as workload characteristics and system configurations.
The Hidden Layers of Dynamic Data Masking in SQL Server
Dynamic Data Masking (DDM) in SQL Server is a feature that helps prevent unauthorized access to sensitive data by obfuscating it at the display level. This blog post discusses the various types of masks available, such as default, email, custom string, and random masks. We explore permissions and access control, demonstrating how users can modify masked data without viewing its actual content. Additionally, we discuss the new permission enhancements in SQL Server 2022 that allow for more granular control over unmasked data.
The Hidden Costs of Over-Indexing SQL Server Tables
Over-indexing in SQL Server can lead to hidden costs that undermine database performance, including increased storage consumption, performance overhead on data modifications, and longer maintenance windows. This article explores how excessive indexing impacts query optimization, disk I/O, and system resources. Learn why a balanced indexing strategy is critical and discover best practices for managing your indexes effectively. Avoid the pitfalls of over-indexing and optimize your SQL Server for both performance and cost-efficiency.