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通用DBMS MVCC 多版本并发控制设计实现

# -*- coding: utf-8 -*-#powered by lixoraimport ConfigParserfrom docxtpl import DocxTemplateimport timeimport sysfrom api.conn_oracle import exec_sqlfrom api.run_cmd import ssh_cmdimport osreload(sys)sys.setdefaultencoding('utf8')os.environ['N

1. import下划线的作用在Golang里，import的作用是导入其他package，但是今天在看beego框架时看到了import 下划线，不知其意，故百度而解之。　　import 下划线（如：import _ hello/imp）的作用：当导入一个包时，该包下的文件里所有init()函数都会被执行，然而，有些时候我们并不需要把整个包都导入进来，仅仅是是希望它执行init()函数而已。这个时候就可以使用 import _ 引用该包。即使用【import _ 包路径】只是引用该包，仅仅是为了.

The size of the buffers in the KEEP buffer pool is the primaryblock size (the block size defined by the DB_BLOCK_SIZEparameter).

验证view与 base table的关系的实验1@首先建一张admin_test表sql>CREATE TABLE admin_test(nameVARCHAR2(20));表已创建。2@接着insert into 一些数据SQL> insert into admin_test(name) values(123);已创建 1 行。SQL> select * from ad

了解数据库的日常操作，有助于我们提前发现可能会发生的问题1.Server-Generated AlertsAlerts are automatically generated when a problem occurs or whendata does notmatch expected values for metrics, such as the following:■ Physic

You lost the PRODSTD tablespace, which was read/write. Thetablespace was read-only when the last backup was performed. How would yourecover the tablespace?最近一次备份时，某表是处于只读状态，后来改成了读写状态。运行一段时间后，这时由

flashrecovery area 空间不够用了1、增加 DB_RECOVERY_FILE_DEST_SIZE的大小increase the value of theDB_RECOVERY_FILE_DEST_SIZEinitialization parameter2、修改保留策略increase the value of the CONTROL_FILE_RECORD_K

scenario:  database operates in ARCHIVELOG mode. User-managed consistent backups are performed every Sunday night. On Tuesday, client A drops a table at 8:00 a.m. as follows: SQL> DROP TABLE c

11gR2 新特性：OracleCluster Health Monitor(CHM)简介https://blogs.oracle.com/Database4CN/entry/11gr2_新特性_oracle_cluster_healthBy JaneZhang(张建英) on 六月 15, 2012Cluster HealthMonitor（以下简称CHM）是一个Oracle提供

使RAC环境稳定运行的首要三件事By Allen Gao on六月 15, 2012from：https://blogs.oracle.com/Database4CN/entry/使rac环境稳定运行的首要三件事确保您的核心数据库基础架构实现高可用性和可扩展性在很多时候是一个复杂的任务。然而，在世界范围内每天有成千上万的Oracle RAC系统都能够成功完成这个复杂的任务。而保证

MEMORY_TARGETPropertyDescriptionParameter typeBig integerSyntaxMEMORY_TARGET= integer[K | M | G]Default value0 (SGAautotuning is disabled for DEFERRED mode autotuningrequest

如何区分一个参数是动态的还是静态的The ISSYS_MODIFIABLE column in V$PARAMETER tells us whether theparameters are static or dynamic. Static parameters require theinstance to be restarted while dynamic parameters can

Incremental backup:增量备份：>0差量备份：>=0Makes a copy of all data blocks that have changed since apreviousbackup. The Oracle database supports two levels of incrementalbackup (0 and 1). Alevel 1 incr

如果当前系统中已有部分用户连入，这是关闭监听，对于已连接的用户而言没有任何影响，但是新用户无法连到数据库中。

undo_tablespaceProperty            DescriptionParameter type      StringSyntax             UNDO_TABLESPACE = undonameDefault value       The first available undo tablespace in the database

对于不熟悉ROWNUM用法的人可以好好的看看了。为什么SELECT * FROM T WHERE ROWNUM=1 可以查询出来数据，而SELECT * FROM T WHERE ROWNUM=2不可以查询出来数据。TOM大师给出ROWNUM计算的逻辑如下：rownum = 1for x in ( select * from A )loopif ( x satisifies the

ORACLE等待事件--《深入浅出ORACLE第八章》 (2009-12-0717:08) 等待事件的源起等待事件的概念大概是从ORACLE 7.0.12中引入的，大致有100个等待事件。在ORACLE8.0中这个数目增大到了大约150个，在ORACLE 8I中大约有220个事件，在ORACLE9IR2中大约有400个等待事件，而在最近ORACLE 10GR2中，大约有874个

1、exportDISPALY=ip:0    2、ECHO$DISPLAY进行查看确认是否设置成功   3、利用xclock尝试2.rpm Header V3 DSA signature: NOKEY 错误解决#rpm -ivh lm_sensors-2.8.8-5.i386.rpmlm_sensors-devel-2.8.8-5.i386.rpm --force --node

【STARTUP】Oracle数据库启动过程中参数文件的使用的顺序及注意事项 1.Oracle在启动数据库过程中参数文件的使用顺序描述这方面的信息在Oracle的官方文档中有比较详细的介绍，文档链接如下，请自行参考。http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/start.htm#sthref512UN

Oracle'sRedoLogEach Oracle database has aredo log. This redo log records all changes madein datafiles.PurposeThe redo log makes it possible to replay SQLstatements.Before Oracle change

11gExternal LOBs A BFILE(binary file LOB) is an external LOB becausethe databasestores a pointer to a file in the operating system. The externaldata is read-only.A BFILEuses a directory object to

Running Health Checks with Health MonitorThis section describes the Health Monitor and includesinstructions on how to use it. The following topics arecovered:About Health MonitorRunning Hea

SecureFile LOBs and BasicFile LOBsSecureFile LOBs (SecureFiles) were introduced in Oracle Database11g Release 1 (11.1) to supplement the original BasicFile LOBsimplementation that is identified by

MERGE PurposeUse the MERGE statement to select rows from one or more sources forupdate or insertion into a table or view. You can specifyconditions to determine whether to update or insert into th

oracle中的INTERVAL 函数详解分类：oracle2010-04-30 11:32 661人阅读 评论(0)收藏 举报INTERVAL YEAR TOMONTH数据类型Oracle语法:INTERVAL 'integer [- integer]' {YEAR | MONTH} [(precision)][TO{YEAR | MONTH}]该数据类型常用来表示

pivoting insert（旋转插入）　　　　这节主要讨论使用pivoting insert 实现将非关系性表记录转换为关系型表中存储。Pivot 旋转是OLAP中的一个基本改变，提供多维度数据分析。比如一个表为sales_source_data,里面的列为　　employee_id number,week_id number,sales_mon number,sales_tuenu

oracle unlock\lock useraccount解锁:SQL>conn sys/password as sysdba;SQL>alter user hr account unlock;由于用户还处于过期状态,所以需要重设密码:SQL> password hr;Changing password for hrNew password: **Retype new p

与NULL值的使用有关:函数                                         含义NVL (expr1,expr2)                       如果expr1为null，则返回expr2NVL2 (expr1, expr2,expr3)               如果expr1不为null，则返回expr2；如果expr1为nul

Enabling Fast Incremental BackupThe minimum size for the block change tracking file is 10 MB,启用块更改追踪：ALTER DATABASE{ENABLE|DISABLE} BLOCK CHANGE TRACKING[USING FILE '...']；-----》可以不用note：You

-------->>>>from otn made by MacLean.liuSQL> create directory dir1 as 'D:\dir1'; Directory created. SQL> create directory dir2 as 'D:\dir2'; Directory created. SQL>SQL> Disconnected from Or

1.查看备份，恢复性能V$BACKUP_SYNC_IOV$BACKUP_ASYNC_IO2.? V$IR_FAILURE:List of all failures, including closed ones (result of the LISTFAILUREcommand)? V$IR_MANUAL_CHECKLIST: List of manual advice (resul

https://updates.oracle.com/Orion/Services/download/p10404530_112030_Linux-x86-64_1of7.zip?aru=14125322&patch_file=p10404530_112030_Linux-x86-64_1of7.ziphttps://updates.oracle.com/Orion/Services/do

原文地址：WITH AS 用法">（转）ORACLE WITH AS 用法作者：jingyun先举个例子吧：有两张表，分别为A、B，求得一个字段的值先在表A中寻找，如果A表中存在数据，则输出A表的值；如果A表中不存在，则在B表中寻找，若B表中有相应记录，则输出B表的值；如果B表中也不存在，则输出"norecords”字符串。 view plaincopyto clipboa

©OraInternals  Riyaj ShamsudeenSCAN,VIP,HAIP,etc.ByRiyaj ShamsudeenBlog: orainternals.wordpress.com ©OraInternals  Riyaj Shamsudeen 2Who am I?  19 years using Oracle products/DBA  OakTable

一个在win下关于配置监听端口的有趣的问题问题场景：一网友想把默认的port=1521 改为port=1523，接着又想改回来。将listener.ora的port改为1521LISTENER =  (DESCRIPTION_LIST =    (DESCRIPTION=     (ADDRESS = (PROTOCOL = TCP)(HOST = PC-20120306AAJY)

beginning with Oracle Database 11g Release 1, database passwordsare case-sensitive. (You candisable case sensitivity and return to pre–Release 11g  behavior by setting the SEC_CASE_SENSITIVE_LOGON

原文地址：452067.1  "How to Configure "kdump" on&nb">Note 452067.1  "How to Configure "kdump" on&nb作者：Hello顾问In this Document  Goal  Solution    How to Configure Kdump  ReferencesApplies to:Linux O

问题描述：环境：oracle10.2.0.5 RAC+HP-UX用analyze index validate structure这个语句可以验证索引的碎片程度，然后通过index_stats视图来查询，请问这个语句在生产库上对于比较大的索引使用这个语句，对系统的影响有多大？FYI：analyze index validate structureSQL> c

一个在win下关于配置监听端口的有趣的问题问题场景：一网友想把默认的port=1521 改为port=1523，接着又想改回来。将listener.ora的port改为1521LISTENER =  (DESCRIPTION_LIST =    (DESCRIPTION=     (ADDRESS = (PROTOCOL = TCP)(HOST = PC-20120306AAJY