Best First算法

Oracle SGA调优规则 在进行Oracle的SGA调优时，遵循一些重要规则至关重要： 确定合适的SGA大小：根据数据库的工作负载动态调整SGA的大小。 优化各个组件：合理配置数据库缓冲区、共享池和大池，以提高性能。 监控使用情况：定期检查SGA的使用情况，及时调整设置以适应变化的需求。 通过以上方法，我们可以有效地提升Oracle SGA的性能，确保系统的稳定运行。

第一章：创建数据库CREATE DATABASE database_name;使用数据库USE database_name;创建表CRATE TABLE table_name ( col2 VAR_TYPE, col1 VAR_TYPE NOT NULL DEFAULT xxx, );删除表DROP TABLE table_name;显示表DESC table_name; DESCRIBE table_name;插入数据INSERT INTO table_name (col1, col2) VALUES (col1_val, col2_val)，还有其他插入数据的方法，不一一详述。

ORACLE学习书籍，英文版的，看书名就知道是关于PL/SQL练习的书，可以尝试一下。

Garbage-First是一种面向多处理器和大内存的服务器风格垃圾收集器，以高概率实现软实时目标，并实现高吞吐量。全堆操作如全局标记与变异并发执行，以防止与堆或活跃数据大小成比例的中断。并发标记既提供了收集的“完整性”，又确定了适合通过紧凑转移进行回收的区域。这种转移在多处理器上并行执行，以提高吞吐量。

Julia Lerman与Rowan Miller合著的关于Code First的权威指南，详尽阐述了其实施原理和代码实现，是程序员必备的学习资源。

资源描述：这份资源将深入介绍在MATLAB中如何有效地操作和应用数组，从基本操作到高级技巧。通过详细的解释和示例代码，您将学习如何在MATLAB中处理各种类型的数据，进行数据分析和解决实际问题。内容概要：该资源首先介绍MATLAB中的数组基础，包括如何创建、访问、修改和操作数组。随后，资源将深入探讨高级数组操作，如多维数组操作、向量化计算和矩阵运算。接着，通过实际示例，演示如何将数组操作应用于数据分析、信号处理、图像处理等领域。适用人群：适用于具备一定数学、工程和编程基础的学习者和开发者。无论您是想学习如何在MATLAB中进行数据处理，还是希望深入了解数组在工程和科学领域的应用，这份资源都将满足您的需求。使用场景及目标：您可以将该资源用于学习如何使用MATLAB进行数据处理、分析和解决实际问题。通过示例代码，您将学会如何进行数组操作，从而在不同领域提升分析能力。

This document outlines best practices for implementing continuous data protection for MySQL databases, illustrated by a case study of the .IE registry's restore process. Best Practices: Regular Backups: Implement a robust backup strategy encompassing full, incremental, and potentially log-based backups to minimize data loss. Backup Validation: Regularly test backups to ensure their recoverability and completeness. Point-in-Time Recovery: Implement mechanisms for point-in-time recovery to restore data to a specific timestamp. Redundancy and Replication: Utilize replication technologies to maintain redundant copies of data and ensure high availability. Disaster Recovery Planning: Develop and regularly test a comprehensive disaster recovery plan that includes backup restoration procedures. .IE Continuous Restore Process: The .IE registry's restore process serves as a case study for continuous data protection. Key elements include: Automated Backups: Automated, frequent backups ensure minimal data loss. Offsite Storage: Secure offsite storage protects backups from local disasters. Regular Testing: Routine testing validates the recoverability of backups. Documented Procedures: Clearly documented procedures streamline the restore process. Benefits: Minimized Data Loss Reduced Downtime Enhanced Data Integrity Improved Disaster Recovery Posture Conclusion: Implementing continuous data protection for MySQL databases is crucial for maintaining data integrity and availability. By adhering to best practices and learning from real-world examples, organizations can significantly reduce the risks associated with data loss and ensure business continuity.

In Oracle, new plans are not used unless they have been validated. The DBA can validate plans at any time or schedule validation during the maintenance window. The optimizer checks if the new plan is equal to or better than the old one. Statement log and Plan history play key roles in the process. If the new plan is as good as or better than the old one, it is added to the plan baseline. Plans that do not perform as well are stored in plan history and marked as unaccepted. During validation, multiple baselines can be tested and the one with the lowest cost will be chosen. This process is particularly useful for volatile tables and cursor sharing scenarios. By default, the retention period for baselines is 53 weeks.

Oracle DBA is a complex system that requires precise configuration and tuning to ensure database security and performance. This article covers multiple aspects of Oracle DBA adjustment and optimization, including password management, performance tuning, log management, and storage management. 1. Password Management is a critical aspect of Oracle DBA, as the security of passwords directly impacts the overall database security. By default, database user passwords expire after 180 days. To prevent this, you can adjust the PASSWORD_LIFE_TIME parameter to control the lifespan of passwords. 1.1 Adjusting PASSWORD_LIFE_TIME: The PASSWORD_LIFE_TIME parameter controls the lifespan of passwords, which is set to 180 days by default. Adjusting this parameter ensures that passwords remain valid without causing database connection issues due to expiration. 2. Performance Tuning is key to maintaining database efficiency. Proper performance tuning can significantly improve the response time and throughput of the database. 1.2 Setting Dump File Size Limit: The size of dump files directly impacts database performance. Setting an appropriate limit for dump file size can enhance database performance. 1.3 Adjusting Default Partition Size: Default partition size adjustments can affect database performance. A reasonable partition size will help improve response time. 1.4 Disabling Automatic Undo Retention Adjustment: Disabling this feature can help optimize database performance. 1.5 Setting Parallel Process Limits: The number of parallel processes directly affects performance. Proper limits can improve database responsiveness. 1.6 Controlling the Retention Time of Control Files: Adjusting control file retention times enhances database security. 1.7 Disabling Delayed Initialization of Extents in 11g: Disabling delayed extent initialization can improve performance. 1.8 Disabling Result Cache: Turning off the result_cache improves performance by reducing resource consumption. 1.9 Disabling Login/Logout Auditing: Disabling login and logout auditing can significantly improve database performance. 1.10 Adjusting AWR Retention Time: Proper AWR retention time helps in optimizing database performance. 1.11 Disabling Adaptive Cursor Sharing: Turning off adaptive cursor sharing will reduce resource consumption and enhance performance. 1.12 Disabling Cardinality Feedback: Disabling cardinality feedback helps improve performance and reduce resource usage. 1.13 Configuring Events 28401 and 10949: Configuring these events can affect database performance and efficiency."

《Head First SQL中文版》是一本以易学易懂著称的SQL入门教材，通过图像和幽默的方式帮助读者掌握SQL数据库的基本概念和操作技能。本书适合初学者和希望通过实际项目提升SQL技能的读者。通过本书，读者可以轻松理解SQL查询语句的构建和数据库管理的基本原理。