为了更好地与IBM 、惠普竞争,Sun近期宣布将在高端Unix服务器中捆绑Oracle的数据库软件,并为用户支付部分软件使用费用。 Sun的具体做法是,当用户购买4 路Sun Fire V490 或更高端、配置UltraSparc IV 或IV+ 芯片的服务器时,Oracle的企业版数据库软件将成为
为了更好地与IBM 、惠普竞争,Sun近期宣布将在高端Unix服务器中捆绑Oracle的数据库软件,并为用户支付部分软件使用费用。Sun的具体做法是,当用户购买4 路Sun Fire V490 或更高端、配置UltraSparc IV 或IV+ 芯片的服务器时,Oracle的企业版数据库软件将成为一个可选配置,Sun将为客户支持Oracle软件的许可费,客户只需支付一年的支持和维护费用。
由于Oracle软件的许可费用是按芯片数量计算的,因此不同服务器的许可费用会有相当大的差别。例如,对于配置有72个双内核芯片的Sun E25K2 服务器而言,Oracle数据库软件的许可费用为85万美元。Sun 首席执行官麦克利尼在Sun-Oracle员工会议上说,用户购买的服务器越高档,得到的津贴就越高,“甚至我们将向客户免费提供Oracle数据库软件。”
Sun 超过半数的销售收入来自低端服务器,它希望与Oracle的这一合作伙伴关系有助于提高其高端机型的业务,IBM在这一市场上势头越来越猛,并不断蚕食Sun 的地盘。“最近两年来,我们在高端领域丢失了市场,这一合作计划的目的是为了收复丢失的市场”,Sun公司一位主管战略的官员辛格说。他指出,通过这一交易,与IBM 基于Power处理器的Unix服务器或惠普基于PA-RISC处理器的Unix服务器相比,在Sun 的服务器上运行Oracle数据库的成本要低约25%。
辛格表示,这项数据库捆绑交易目前不包括Sun 的UltraSparc T1 系统或Galaxy系列x86 服务器。
据悉,Sun和Oracle的这项数据库捆绑交易计划中还包括联合营销和广告方面的动作。两家公司还宣布,Oracle将把许可Sun 的Java软件技术的时间再延长10年。埃利森表示,Oracle正在对其利用了Java技术的应用软件进行升级。而一向出言不逊的麦克利尼还赞扬了Oracle在协助开发Java方面所发挥的重要作用。
两个IT领域著名的“口水领袖”麦克利尼和埃利森能够同台演讲,是Sun和Oracle两家公司在最近数月中不断修复关系的结果。2003年,Oracle声称Linux 将成为其主要的软件开发平台,这伤害了Sun 的Solaris。到了2005年11月份,Oracle又改变了立场,声称Solaris 是64位x86 芯片的“首选开发和部署平台”。
虽然两家公司已经达成了捆绑销售的合约,但是一向爱发牢骚的麦克利尼还抱怨了Oracle的按芯片内核计算软件许可价格的价格策略。他说:“在服务器市场上,Sun 有着最为积极的多内核芯片战略,Oracle的价格策略使我们在价格方面处于不利地位。”
Sun与Oracle的“付费”交易并非是独家交易,Sun 仍然可以捆绑其他数据库软件。

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB

MySQL/InnoDB supports four transaction isolation levels: ReadUncommitted, ReadCommitted, RepeatableRead and Serializable. 1.ReadUncommitted allows reading of uncommitted data, which may cause dirty reading. 2. ReadCommitted avoids dirty reading, but non-repeatable reading may occur. 3.RepeatableRead is the default level, avoiding dirty reading and non-repeatable reading, but phantom reading may occur. 4. Serializable avoids all concurrency problems but reduces concurrency. Choosing the appropriate isolation level requires balancing data consistency and performance requirements.

MySQL is suitable for web applications and content management systems and is popular for its open source, high performance and ease of use. 1) Compared with PostgreSQL, MySQL performs better in simple queries and high concurrent read operations. 2) Compared with Oracle, MySQL is more popular among small and medium-sized enterprises because of its open source and low cost. 3) Compared with Microsoft SQL Server, MySQL is more suitable for cross-platform applications. 4) Unlike MongoDB, MySQL is more suitable for structured data and transaction processing.

MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.

The MySQL learning path includes basic knowledge, core concepts, usage examples, and optimization techniques. 1) Understand basic concepts such as tables, rows, columns, and SQL queries. 2) Learn the definition, working principles and advantages of MySQL. 3) Master basic CRUD operations and advanced usage, such as indexes and stored procedures. 4) Familiar with common error debugging and performance optimization suggestions, such as rational use of indexes and optimization queries. Through these steps, you will have a full grasp of the use and optimization of MySQL.

MySQL's real-world applications include basic database design and complex query optimization. 1) Basic usage: used to store and manage user data, such as inserting, querying, updating and deleting user information. 2) Advanced usage: Handle complex business logic, such as order and inventory management of e-commerce platforms. 3) Performance optimization: Improve performance by rationally using indexes, partition tables and query caches.


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