调优目的: 1.  提高资源利用率 2.  找出性能瓶颈并缓解 3.  通过性能管理实现合理的资源分配,提升硬件性价比 调优分层及效率问题: 业务级调优  eg:1)网站使用的Apache—>业务架构 2)将原有调度器由LVS—>F5/BigIP 3)将原有的调度器由Nginx转换成Haproxy 4)购买CDN.静态页缓存等 效果最佳 应用级调优  eg:NFS.Samba.Apache.Nginx.MySQL.KVM本身调优.对于日志处理可调整日志等级或延后日志写以避免大量I/O操作. 重…

对Oracle数据库整体性能的优化,首先要关注的是在有性能问题时数据库排名前几位等待事件是哪些.Oracle等待事件众多,随着版本的升级,数量还在不断增加,可以通过v$event_name查到当前数据库版本包含的等待事件.例如我在Linux平台查11.2.0.4版本的Oracle是有1367个等待事件.SELECT name FROM V$EVENT_NAME ORDER BY name; 如此多的等待事件自然是要分类汇总,并对常见的等待事件有比较深入的认识,才能在Oracle数据库调优这条路上…

Tuning Methodology When dealing with performance problems, database professionals tend to focus on the technical aspects of the system, such as resource queues, resource utilization, and so on. However, users perceive performance problems simply as w…

A Complete Tutorial on Tree Based Modeling from Scratch (in R & Python) MACHINE LEARNING PYTHON R   SHARE      MANISH SARASWAT, APRIL 12, 2016 / 52     Introduction Tree based learning algorithms are considered to be one of the best and mostly used s…

Bruce Momjian POSTGRESQL is an object-relational database developed on the Internet by a group of developers spread across the globe. It is an open-source alternative to commercial databases like Oracle and Informix. POSTGRESQL was originally develop…

第二章 Ergonomics Ergonomics is the process by which the Java Virtual Machine (JVM) and garbage collection tuning, such as behavior-based tuning, improve application performance. The JVM provides platform-dependent default selections for the garbage col…

http://java.dzone.com/articles/performance-tuning For most typical Spring/Hibernate enterprise applications, the application performance depends almost entirely on the performance of it's persistence layer. This post will go over how to confirm that…

本文的目的不完全在于提供调优信息,而是在于告诉读者了解Linux kernel如何处理数据包,从而能够在 自己的实践中发挥Linux 内核协议栈最大的性能 The NIC ring buffer 接收环缓冲区在设备驱动程序和NIC之间共享. 网卡分配发送(TX)和接收(RX)环形缓冲区. 环形缓冲区是一个循环缓冲区,其中溢出只是覆盖现有数据. 应该注意,有两种方式将数据从NIC移动到内核,硬件中断和软件中断(也称为SoftIRQ). RX环形缓冲区用于存储传入的数据包,直到它们被设备驱动程序处理…

1.2性能调优特性和工具 Effective data collection and analysis isessential for identifying and correcting performance problems. Oracle providesa number of tools that allow a performance engineer to gather informationregarding database performance. In addition t…

老李分享: Oracle Performance Tuning Overview 翻译   poptest是国内唯一一家培养测试开发工程师的培训机构,以学员能胜任自动化测试,性能测试,测试工具开发等工作为目标.如果对课程感兴趣,请大家咨询qq:908821478,咨询电话010-84505200. 1 性能优化概述 This chapter provides an introduction toperformance tuning and contains the following secti…