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weejar zhang I had an issue while dropping a mssql user today, I was unable to drop the user and it failed with the user in an read_only db. I had many db in the server(more than 200),and many read-only db,so To delete an user must setting there DB to read write status.
In Linux, PTS stands for Pseudo Terminal Slave. PTS refers to a user currently logged in to your terminal using an SSH or telnet connection.
Both “db file sequential read” and “db file scattered read” events signify time waited for I/O read requests to complete.
We know that changed a normal user password has no diffrence between a single instance database and a RAC database,we just have to perform “alter user xxx identified by xxx” and the password will be cheanged.
根据AWR的收集信息查询出指定时间段内的逻辑读最高的几个对象，script
OGG可以是否从SOURCE db 一个非分区表到TARGET db 的一个分区表的同步么？DDL/DML是否都可以？
有时出于安全考虑限制个别用户只允许特定程序连接或连接数，比如下面的例子是只允许ANBOB用户使用pl/sql dev连接此数据库。
Oracle Database provides a means for suspending, and later resuming,
the execution of large database operations in the event of space allocation failures.
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The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical bonded interface.
Now I used segment advisor performs analysis on the segments and makes recommendations on how space can be reclaimed…
Some scripts for showing the growth of tablespaces over time periods. to show the starting tablespace size and the end tablespace size, computing the tablespace growth for the time period.
内存管理是一个非常复杂的结构，在操作系统中用Virtual memory System进行内存管理，pagetable是中记录了内存的虚拟地址和物理地址的映射关系，当一个进程真正的访问数据是首先访问的是page table然后转向真实的地址，cpu中有固定的大小来缓存部份的pagetables,这块区域就是translation lookaside buffer(TLB).
通过检查replicate进程确认OGG REPLICATE进程是否存活shell
今天查看AWR时，发现有个sql占用的cpu很高而且也并不复杂，top 5 event出现了cpu,read by other sessions,而且sql中再次看到的hint index,随后从生产环境中拿到绑定变量参数值进行本地调试，发现hint index 选择了错误的索引一致读为93万，去掉hint立即降低到了36，随后服务器压力将了下来
usually,we do not want to setup an email serve,but just want to send an email from a Linux Shell script easily when got any alert or exptions.then let’s know what happend with the event on the Host,then to solve this problem.
The log file switch – checkpoint incomplete event tells you that Oracle wants to reuse a redo log file, but the current checkpoint position is still in that log file. This results in redo generation being stopped until the log switch is done.
Bing determines bandwidth on a point-to-point link by sending ICMP ECHO_REQUEST packets and measuring their roundtrip times for different packet sizes on each end of the link
经常见到select * from table(function(args))的查询方法,对pl/sql 强大功能赞不绝口,比如PIPELINED 管道函数
例子
sometimes we use ALTER SESSION statement to set or modify any of the conditions or parameters that affect your connection to the database. The statement stays in effect until you disconnect from the database. we can query current system Initialization parameter from v$parameter view,but where are able to confirm that the session-level parameter modification happened?