一般使用iostat命令监控I/O性能1.iostat命令可用参数列表: OPTIONS -c Display the CPU utilization report. -d Display the device utilization report. -h Make the NFS report displayed by option -n easier to read by a human. -k Display statistics in kilobytes per second inste…
该特性主要针对 统计信息陈旧.无直方图或虽然有直方图但仍基数计算不准确的情况, Cardinality基数的计算直接影响到后续的JOIN COST等重要的成本计算评估,造成CBO选择不当的执行计划 Oracle Database - Enterprise Edition - Version 11.2.0.1 and laterInformation in this document applies to any platform. PURPOSE This document records a…
101.Identify two situations in which you can use Data Recovery Advisor for recovery. (Choose two.) A. The user has dropped an important table that needs to be recovered. B. The database files are corrupted when the database is open. C. You are not ab…
前言 经常做系统分析会接触到很多有用的工具,比如 iostat,它是用来分析磁盘性能.系统 I/O 的利器. 本文将重点介绍 iostat 命令的使用,并分析容易引起误解的几个指标. iostat iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions. 上面是 man 手册关于 iostat 命令的介绍,非常简单明了.iosta…
vmstat 字段含义 Procs r: The number of processes waiting for run time. 等待执行的进程, 数字越大意味着CPU越忙, 果该数字经常大于逻辑cpu个数则CPU资源存在瓶颈 b: The number of processes in uninterruptible sleep. 处在非中断睡眠状态的进程数, 即进程被阻塞, 主要是指被资源阻塞的进程对列数(比如IO资源, 页面调度等), 当这个值较大时需要根据应用程序来进行分析,比如数据库…
In this post, I will give a list of all undocumented parameters in Oracle 12.1.0.1c. Here is a query to see all the parameters (documented and undocumented) which contain the string you enter when prompted: – Enter name of the parameter when prompted…
In this post, I will give a list of all undocumented parameters in Oracle 11g. Here is a query to see all the parameters (documented and undocumented) which contain the string you enter when prompted: – Enter name of the parameter when prompted SET l…
/* This work is licensed under Creative Commons GNU LGPL License. License: http://creativecommons.org/licenses/LGPL/2.1/ Version: 0.9 Author: Stefan Goessner/2006 Web: http://goessner.net/ */ function json2xml(o, tab) { var toXml = function(v, name,…