ITPub博客

三、查询热点块和热点对象statspack报告中latch的竞争比较突出，见如下：Latch Name Requests Misses Sleeps Sleeps 1->4-------------------------- -------------- ----------- ----------- ------------cache buffers chains 105,398,981 27,571 361 27232/317/22NoWait WaiterLatch Name Where Misses Sleeps Sleeps------------------------ -------------------------- ------- ---------- --------cache buffers chains kcbrls: kslbegin 0 290 7cache buffers chains kcbgtcr: fast path 0 57 43cache buffers chains kcbgtcr:

二、Parent and Child LatchesMost internal Oracle data structures that are protected by latches are protected by only one latch. However, in some cases more than one latch may be used. For example, there may be a number of library cache latches protecting different groups of objects in the library cache, and separate cache buffers chains latches are used to protect each of the database buffer cache hash chains.[@more@]Whenever a number of latches may be used to protect different parts of a struct

一、Latch and LockLatches are the more restrictive mechanism, because they do not allow multiple processes to inspect the protected data structure at the same time—they provide for exclusive access only.[1] Locks allow for better concurrency, because they may be held in a shared mode when the data structure is simply being inspected.[1] This is a simplification. The redo copy latches can be shared, but this is hardware dependent.[@more@]Another significant difference between locks and latches i

Waits are timed if and only if the TIMED_STATISTICS parameter is set to TRUE.Let me endorse what others have said before, that the overhead of timed statistics is negligible. If you need to convince yourself, use the SET TIMING ON command in SQL*Plus to measure the elapsed time of a benchmark query. Use an otherwise idle system and take ten or more measurements with and without timed statistics. You will be hard pressed to discern any significant difference.[@more@]Without timed statistics, Orac

A lecturer was giving a lecture to his student on stress management. He raised a glass of water and asked the audience, ”How heavy do you think this glass of water is?”The students’ answers ranged from 20g to 500g.[@more@]“It does not matter on the absolute weight. It depends on how long you hold it. If I hold it for a minute, it is OK. If I hold it for an hour, I will have an ache in my right arm. If I hold it for a day, you will have to call an ambulance. It is the exact same weight, but t

It has been so bitterly cold here in Pennsylvania.I can’t remember a winter being as cold as this, but I’m sure there were colder days.Even though the daylight hours are growing longer minute by minute, it’s easy to find an excuse not to go out unless you absolutely must, but then again I often have to push myself to accomplish things.[@more@]People I speak to have been in all kinds of nasty moods. They say they’re “under the weather,” not feeling good about this time of year.As I stood ou

因一现网问题需将特定日期内的表日志数据导出供分析，我协助提供了如下的shell脚本：[@more@]#!/usr/bin/shcd /oracle#create usersqlplus -s /nolog <<EOF >/dev/nullconnect portal/portaldrop table op_log_syh;create table op_log_syh as select * from op_log where to_char(op_date,'yyyymmdd') in ('20071008','20071009','20071010','20071011');exit;EOFecho 'Geted the need data from table OP_LOG.'$ORACLE_HOME/bin/exp portal/portal file=/oracle/op_log_syh.dmp tables=op_log_syh consistent=y buffer=5000000

Export: Release 9.2.0.1.0 - Production on 星期四 10月 11 11:01:11 2007Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.连接到: Oracle9i Enterprise Edition Release 9.2.0.4.0 - ProductionWith the Partitioning, OLAP and Oracle Data Mining optionsJServer Release 9.2.0.4.0 - Production已导出 ZHS16GBK 字符集和 AL16UTF16 NCHAR 字符集[@more@]. 正在导出 pre-schema 过程对象和操作EXP-00008: 遇到 ORACLE 错误 4068ORA-04068: existing state of packages has been discardedORA-04063: package bod

1. There are some good reasons for... There are two reasons for the improvement in people's living conditions. In the first place, we have been carrying out the reform and opening-up policy. Secondly, there has been a rapid expansion of our national economy. Furthermore, the birth rate has been put under control. [@more@]2. My suggestions to deal with the problem are as follows. In the first place, ... Secondly, ... Finally, ... My suggestions to deal with the problem are as follows. In the firs

OTC是英文Over The Counter的缩写，在医药行业术语中特指非处方药。我国卫生部医政局对非处方药是这样定义的：OTC是消费者可不经过医生处方，直接从药房或药店购买的药品，而且是不在医疗专业人员的指导下就能安全使用的药品。非处方药的主要类别：饮食补充剂（包括维生素、矿物质）、皮肤用药（包括皮肤保健品）、感冒咳嗽药、止痛药、胃肠病药。[@more@]

　　从前，有位乡下青年，读了点书，嫌乡村的生活单调，决定要去城里闯世界。临走时，他向村中的村长请教，村长给了他三个字的忠告：“不要怕”。并讲好等他回来时还有另三个字相赠。三十年后，饱经风霜的青年带着满头白发决定还是回乡村生活。回来时，得知当年的村长已死，心中怅然若失，不知村长另外要赠的三字是什么？村长的儿子转交给他一个信封，说是长者临死前嘱咐交给他的。信只有三个字：“不要悔”。[@more@]　　赌博的故事　　这是则老故事。中国以前流行赌骨牌。骨牌共有 36 个数字，从 1 到 36。赌客任押其中一个数字，庄家开

公司测试部一数据库无法正常启动，找到了我帮忙解决！具体故障现象如下：SQL> startupORACLE instance started.Total System Global Area 353857616 bytesFixed Size 737360 bytesVariable Size 318767104 bytesDatabase Buffers 33554432 bytesRedo Buffers 798720 bytesDatabase mounted.ORA-00368: checksum error in redo log blockORA-00353: log corruption near block 74032 change 1121332681927 time 09/25/200710:47:51ORA-00312: online log 3 thread 1: '/oracle/oradata/ora9i/redo03.log'[@more@]提示在线日志文件遭到了

昨天在建一分区表时抛了异常“ORA-14039: 分区列必须构成 UNIQUE 索引的关键字列子集”，具体过程如下：[@more@]SQL> begin2 execute immediate3 'create table MSG_STORAGE_CACHE4 (5 NAME VARCHAR2(64) not null,6 HASHKEY VARCHAR2(100) not null,7 PACKAGE VARCHAR2(3000) not null,8 CREATEDATE DATE default SYSDATE9 )10 partition by range(CREATEDATE)11 (12 partition p_'||to_char(sysdate-6,'yyyymmdd')||' values less than(to_date('''||to_char(sysdate-5,'yyyymmdd')||''',''yyyymmdd'')),13 partition p_'||to_char(s

同事反映应用中获取到的sequence的nextval值存在问题，从获取时间上来看不是递增的。一表中列SN的取值来源于序列TB_C_DATA_ALTER_LOG_SEQ，14：50插数据时SN为4081，而15：11插数据时SN反而变小了，为4062。经分析得知该序列采用了cache 20的默认选项。[@more@] 单实例的数据库倒不存在这个问题，RAC中就会出现先取的值不一定是小的，后取的值不一定会大的问题。具体原因是由于rac两节点中若序列的cache为20的话，在节点一上cache了1－20个，然后节点二上cache了20－40。当从不同的节点来进行对sequence取值的时候，会

[root@PORTAL3115 root]# export DISPLAY=10.1.19.134:0[root@PORTAL3115 root]# xterm[root@PORTAL3115 root]# gnome-session&[@more@]_

expense.current expenses、selling expenses、travelling expensesadmission.admission by ticket onlycharge.what are the charges in the hotel?cost.The cost of seeing a movie is seven dollars.fare.All fares,please.[@more@]

性能测试时发现阻塞在数据库端，测试人员找到了我。通过查询v$session_wait后发现基本上是datafile和redo文件的读写等待事件。监控时发现主机的cpu和内存还正常，loadrunner压力时发现入库操作（往表插数据阻塞）一直影响其他进程，对数据库作了statspack后发现往一张表中插入数据消耗了大量的buffer get。查看该表的存储参数后发现INITIAL_EXTENT为64K，NEXT_EXTENT为空，该表对应的表空间的ALLOCATION_TYPE为UNIFORM。在这种情况下表数据扩张时每次申请新的extent的大小为64k。由于是非常频繁插入数据，显然每次扩张64K的大小太小了，导

最近在浏览一项目的第三方软硬件汇总表时，看到了oracle数据库的报价如下：产品名称版本使用权类型用户数发货数量使用权单价使用权费用Oracle 9i enterprise edition9iFU4001￥9,932.00￥3,972,800.00Partitioning9iFU4001￥2,483.00￥993,200.00Performance Tuning Pack9iFU4001￥745.00￥298,000.00Diagnostic Pack9iFU4001￥745.00￥298,000.00Change Management Pack9iFU4001￥745.00￥298,000.001.4 数据库的售后服务　　　　　　数量产品说明单价小计1Oracle基本技术支持服务/年(系统列表价22%):￥1,289,200.00￥1,289,200.00　　　

Oracle Management Service (OMS)Oracle HTTP Server (OHS)Oracle Application Server Containers for J2EE (OC4J)Enterprise Manager (EM)Distributed Configuration Management Control (dcmctl)Oracle Process Management Notification Control (opmnctl).Oracle Management Repository (OMR)Database Configuration Assistant (DBCA)[@more@]Automatic Storage Management (ASM)Oracle HTTP Server (OHS)Distributed Configuration Management Control (dcmctl)Oracle Process Management Notification Control (opmnctl)High-water m

Base statistics represent the raw data collected. For example, counting the number of physical reads in the system since startup is a base statistic.Metrics are secondary statistics derived from base statistics. Most metrics track the rates of change of activities in the Oracle database. For example, the average physical reads in the system in the last 60 minutes is a metric. Metrics are used by internal client components forsystem health monitoring, problem detection, and self-tuning.[@more@]Fo