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It is widely known that the Oracle server uses kslgetl – Kernel Service Lock Management Get Latch function to acquire the latch,oradebug call kslgetl/kslfre can be used to acquire the latch manually. This is very useful to simulate latch related hangs and contention.
今天开发的同事问有个表上的数据为什么删不掉？我看了一下，也就不到100000条数据，表上有外键，等了5分钟hang在那里…
《Know More about Oracle AWR》 姐妹篇，oracle 10g引入，ASH 是性能诊断工具，不像sql trace总是默认打开， 保存历史上发生了什么， 提供比AWR更细粒度的数据，即使当系统负载很高时，它也工作的很好，因为使用类似memcopy的数据收集，不会有太大的额外负担，没用任何类型的数据库lock。 Active(‘Active’ == Non-idle sessions) Session History Licensed as part of the Diagnostic pack,
一段时间以来，Oracle在此领域的解决方案一直是其内置工具Statspack。Oracle数据库10g进行了重大改进：自动工作量存储库（AWR）。AWR与数据库一起安装，不仅捕获统计信息，还捕获捕获的指标。
在分页查询或top n中在oracle 之间的版本使用rownum,row_number..，从12c 提供了offset fetch 的语法，其实这个语法不是什么新鲜玩意，在DB2,MSSQL,MYSQL,PostgreSQL之前也都提供的语法。
在12c以前如果想移动表空间的数据文件首先要offline.再OS mv命令移动离线的数据文件到新路径，Recover datafile[ or tablespace or database] 再Online.从12c 开始可以移动Online 的数据文件了。
前两天对oracle数据库(single instance)进行了迁移升级从10.2.0.4 升到11.2.0.3，有一个项目迁完后第二天，cpu负载升到了130更高（16cpus）. 向用户询问后使用上没有改变，平时就几个人使用，而该用户活动会话就有100多个。最在等待CBC latch. 怀疑是执行计划发生了改变。
Database Architecture consists of
1) Container Database (CDB)
2) Pluggable Database (PDB)
# make direcory for backset file and scripts file,in my case /backup/db_bak cd /backup/db_bak mkdir scripts logs rman # the following is contents of rman_backup_sh vi /backup/db_bak/scripts/rman_backup_sh #!/bin/bash # author: anbob.com # desc: rman backup database level 0 # contact: weejar@gmail.com export ORACLE_HOME=/oracle/product/11.2.0/db_1 export ORACLE_SID=pora40 RMAN_LOG_FILE=/backup/db_bak/logs/rman_database_backup.`date +%y%m%d%H%M`.out # —————————————————————– # Initialize the log file. # … Read more
当做EXPDP 逻辑备份时常用到FULL=Y 的全库备份,但是有些schema不想每次都备份如一些自带的schemas(如APEX_030200),这时可以使用exclude很方便的排除…
log file sync wait 默认是发生在前台进程发进commits时比如用户commit,DDL,递归操作发生在dictionary table 上的DML,同时rollback 也会导致…
Oracle support request hang analysis and system state dumps when rasing SR. One 10.1 or higher versions login as sqlplus -prelim / as sysdba To do a hanganalyze oradebug setmypid; oradebug unlimit; oradebug hanganalyze 3; Wait 60 – 90 seconds and run the last command again to identify the process state changes. To get a … Read more
当需要写shell连接数据库取一些数据或备份等操作时，shell中可能包含数据库的用户密码等敏感信息，被一些不怀好意的人发现是你的灾难，出于安全的考虑需要对shell明文加密，使用shc 就可以把原shell编译为可执行程序(二进制)，这样就无法再明文打开shell。
Manually create physical standby with rman;
Primary role and Primary standby role switchover;
Converting Physical Standby to Logical Standby ;
The CTAS operation although copies column constraints such as NULL, NOT NULL from the normal table to the partitioned table during the partitioned table creation, it does not copy DEFAULT VALUEs of the columns.
[oracle@db231 ~]$ ./adr_purge
INFO: Purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purge started at Thu May 16 07:35:32 CST 2013
INFO: adrci purging diagnostic destination diag/tnslsnr/db231/listener
INFO: purging ALERT older than 90 days …
INFO: purging INCIDENT older than 30 days …
ORA-12012: error on auto execute of job 88
ORA-12034: materialized view log on “TOPBOX”.”TOPBOX_COURSESTUDY” younger than last refresh
ORA-06512: at “SYS.DBMS_SNAPSHOT”, line 2256
A few days ago a friend ask me to see a awr issue. In the TOP 5 Times Events, as you see, Obviously,database has relatively high sbtbackup wait event, Backup:sbtbackup falls under the administrative category also realted to the RMAN. These wait events will occur when there is RMAN backup running on the server. Backup: … Read more
因一次硬件原因导致了服务器异常停机，防止蝴蝶效应及时进行了数据迁移，一周发现了这个决定正确的。 申请了2小时的停机时间。因数据不大且表空间开始使用不规范决定用expdp数据泵方式迁移。 在新设备 1, raid10+安装OS 2，安装oracle 10.2.0.1(single instance)+ 3，升级oracle 10.2.0.5 4，建库, 5, 调整INSTANCE参数,调整temp tbs、redo file size、undo tbs大小 6，创建app schema、创建data\index tablespace 用时1小时左右 stop web app+挂通知 stop listener sys@TOPBOX>select object_type,count(*) cnt from dba_objects where owner=’TOPBOX’ GROUP BY OBJECT_TYPE; OBJECT_TYPE CNT ——————- ——————– SEQUENCE 802 PROCEDURE 25 DATABASE LINK 2 LOB 3 TRIGGER 3 MATERIALIZED VIEW 2 TABLE … Read more
It all started in January 2005 with Critical Patch Updates (CPU). Then Patch Set Updates (PSU) were added as cumulative patches that included priority fixes as well as security fixes.