Showing posts with label Query Store. Show all posts
Showing posts with label Query Store. Show all posts

Monday, 4 March 2024

Understanding the SQL Server Query Optimiser: A Comprehensive Overview

The SQL Server Query Optimiser is a crucial component of Microsoft SQL Server, responsible for determining the most efficient way to execute a given query. The optimiser takes into consideration various factors, including the structure of the query, available indexes, statistics about the data, and the overall database schema. Here is a detailed breakdown of its functionalities, processes, and related concepts. 

1. Purpose of the Query Optimiser

The primary goals of the Query Optimiser include:

  • Generating Execution Plans: The optimiser creates a roadmap that describes how SQL Server will access the data required by the query.
  • Maximising Efficiency: By evaluating different potential execution paths, the optimiser selects the one that minimises resource utilisation, such as CPU, memory, and disk I/O.
  • Improving Response Times: A well-optimised query results in faster execution, contributing to better overall system performance.

Monday, 13 February 2023

New Features in SQL Server 2022 for Developers

SQL Server 2022 brings a comprehensive suite of features designed to enhance the development experience, improve performance, and strengthen security. By leveraging these capabilities, developers can create more efficient, scalable, and secure applications, positioning their organisations to effectively handle modern data challenges and requirements. The focus on intelligent processing, machine learning, data integration, and robust security aligns with the evolving landscape of application development and data management.

Here’s a detailed overview of the new features in SQL Server 2022 tailored for developers.

1. Intelligent Query Processing Enhancements

Overview: SQL Server 2022 continues to build on the Intelligent Query Processing (IQP) capabilities introduced in previous versions. The aim is to enhance query performance automatically without requiring significant code changes. This means that developers can achieve better performance for their applications without extensive rewrites.

Key Feature:

  • Parameter Sensitive Plan Optimisation: This feature allows SQL Server to create and maintain multiple execution plans for the same query based on different parameter values. It identifies the most efficient plan based on runtime parameter values rather than relying solely on the static plan generated during compilation.

Example Scenario: Consider a financial application that retrieves transaction records based on different filters, such as dates and account numbers. With parameter-sensitive plan optimization, SQL Server will adaptively select the best execution plan based on the most commonly accessed account numbers or date ranges, leading to reduced execution times and better resource utilisation.

2. Built-in Machine Learning Services

Overview: SQL Server 2022 provides built-in support for machine learning services directly within the database engine. This integration allows developers to run R and Python scripts without the need for external tools.

Key Features:

  • Direct Data Access: R and Python scripts can access SQL Server data directly, allowing for real-time analysis without the need to export data to another platform.
  • Model Deployment: Developers can train and deploy machine learning models directly within SQL Server, making it easier to use these models in production applications.
  • Scalability: Since machine learning is performed on the SQL Server instance, it can take advantage of the existing hardware resources, which may lead to improved performance for large datasets.

Example Scenario: A marketing department might use machine learning to predict customer churn. By training a model directly within SQL Server, they can continuously feed it fresh data from their transactional systems, enabling real-time predictions that can drive immediate business actions, such as targeted retention strategies.

3. SQL Server Ledger

Overview: SQL Server Ledger introduces a new feature that provides blockchain-like functionality, enabling developers to build applications with strong data integrity and immutability. This is particularly useful for industries that require stringent audit trails and data verification.

Key Features:

  • Immutable Ledger Tables: These tables track all transactions in a way that prevents any modifications after they are committed, creating an audit trail that can be independently verified.
  • Cryptographic Verification: Each transaction is cryptographically hashed, and the hashes are stored in the ledger, ensuring the integrity and authenticity of the data over time.
  • Integration with Existing Systems: Developers can integrate ledger functionality with existing applications seamlessly, making it easier to adopt this technology without major architectural changes.

Example Scenario: In a healthcare application, patient treatment records can be stored in a ledger table. Each update to a patient’s treatment plan is recorded in a way that cannot be altered, providing a verifiable history that meets regulatory compliance and can be audited as needed.

4. Enhancements to Query Store

Overview: The Query Store feature is designed to help developers manage query performance by providing historical data on query execution, plan choices, and runtime statistics. The enhancements in SQL Server 2022 provide deeper insights and improved capabilities for tracking query performance over time.

Key Features:

  • Query Performance Insights: The enhancements include improved reporting capabilities, allowing developers to visualize query performance trends over time and quickly identify any regressions.
  • Automatic Plan Correction: SQL Server can automatically identify when a query's performance has degraded and revert to a previously optimal execution plan, reducing the need for manual intervention.
  • Improved Visibility into Query Execution: Developers can see detailed information about query execution times, resource consumption, and plan changes, making it easier to diagnose performance issues.

Example Scenario: A web application might experience slowdowns after a new feature is deployed. Developers can use the Query Store to identify which queries have started to perform poorly, understand the reason behind the changes, and either optimise the queries or revert to a better-performing plan.

5. Azure Synapse Link for SQL Server

Overview: Azure Synapse Link provides a seamless integration between on-premises SQL Server databases and Azure Synapse Analytics, enabling developers to perform analytics on operational data without the need to move data to the cloud.

Key Features:

  • Near Real-Time Analytics: Developers can run analytics on data as it is ingested, allowing for timely insights that can influence business decisions.
  • Simplified Data Pipelines: This integration allows for the creation of streamlined data pipelines, enabling developers to focus on analysis rather than data movement.
  • Enhanced Reporting: Azure Synapse provides powerful analytical capabilities that can be directly applied to operational data, enhancing reporting and decision-making.

Example Scenario: An e-commerce company can use Azure Synapse Link to analyse customer behaviour in real-time. By connecting their on-premises SQL Server to Azure Synapse, they can quickly generate reports on customer purchasing patterns, allowing for immediate marketing adjustments based on current trends.

6. Enhanced Security Features

Overview: SQL Server 2022 introduces several new security enhancements designed to protect sensitive data and improve overall database security posture.

Key Features:

  • Always Encrypted with Secure Enclaves: This enhancement allows certain operations to be performed on encrypted data without exposing it in plaintext, enhancing the security of sensitive information.
  • Dynamic Data Masking Enhancements: These improvements offer developers more options for controlling how sensitive data is presented to users, allowing for greater flexibility in displaying data according to user roles.
  • Security Monitoring Tools: New tools provide real-time alerts and recommendations for improving database security, helping developers maintain compliance with best practices.

Example Scenario: In a banking application, sensitive information such as customer account details can be protected using Always Encrypted. Developers can configure dynamic data masking to ensure that only authorised personnel can view sensitive data, thus enhancing customer trust and compliance with regulations.

7. SQL Server Management Studio (SSMS) Enhancements

Overview: The latest version of SQL Server Management Studio includes significant enhancements designed to improve the developer experience, making it easier to manage and develop SQL Server databases.

Key Features:

  • Improved IntelliSense: Enhanced IntelliSense capabilities help developers write SQL queries more efficiently by providing better auto-completion and suggestions.
  • Integrated Monitoring Tools: New monitoring features allow developers to track database performance metrics directly within SSMS, enabling faster troubleshooting and optimisation.
  • User-Friendly Interface: A more intuitive user interface makes it easier for developers to navigate complex database structures and management tasks.

Example Scenario: A developer working on a complex SQL query can rely on the improved IntelliSense features to quickly find the right syntax and suggestions, reducing errors and speeding up the query development process.

8. Support for UTF-8 Encoding

Overview: With the introduction of UTF-8 encoding support, SQL Server 2022 allows developers to store and manipulate multilingual data more effectively, which is crucial for global applications.

Key Features:

  • Flexible Data Storage: Developers can specify UTF-8 encoding when creating string columns, enabling efficient storage of various character sets.
  • Reduced Storage Requirements: By using UTF-8 encoding, developers can save space compared to UTF-16 encoding, particularly for texts primarily in English or other Latin-based languages.
That's all for now.
HELLO, I'M PERCY REYES! I've been working as a senior SQL Server Database Engineer for over 20 years; I'm a three-time Microsoft Data Platform MVP. I'm a cryptographer conducting research on cryptographic Boolean functions and their applications.