HAVING expression default Selectivity
In some cases the query optimizer might can not accurately estimate cardinality (e.g. group by having or like with bind variables cause etc..),therefore the Cardinality estimates are based on default seletivity of build-in oracle coredefault seletivity(5%).
oracle forall instructs must be followed by DML
Oracle BULK COLLECT and Oracle FORALL are the new featu […]
goldengate extract process abending caused by nologging DDL
I use goldengate(for oracle) to do a SCHEMA synchronize […]
US7ASCII DMP 导入 ZHS16GBK DB 一方案
exp 时注意保证三处的字符集一致，对于本例的US7ASCII(10g) DMP 导入 ZHS16GBK DB (11g),采用了修改dmp文件中的两处字符集编号，最终解决了字符集乱码问题。
The lowercase and quotes table names may not be able to audit(小写表名可能不会审计)
昨一好朋友问我开了审计，有些表但无审计记录。 下面我来还原这个问题 db_version oracle 102 […]
ORA-1688: unable to extend table SYS.WRH$_ACTIVE_SESSION_HISTORY
1) Export the snapshots and then do a manual purge To p […]
batch change read only DB in mssql 2K
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.
How TO Kill and Logout users in pts/* Linux
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.
DB File Sequential and Scattered Reads
Both “db file sequential read” and “db file scattered read” events signify time waited for I/O read requests to complete.
Changing SYS Password in RAC (修改SYS密码)
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.
Script: TOP logical read within a specific time period(指定时间逻辑读最多的对象)
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
goldengate supports sync data from no-partition table to partition table(OGG同步非分区表到分区表)
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？
How to limit program access to database(限止连接数据库使用程序)
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。
statement suspended, wait error to be cleared(二)
Oracle Database provides a means for suspending, and later resuming,
the execution of large database operations in the event of space allocation failures.
Bonding Network Interfaces on LINUX5
The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical bonded interface.
How to check and reclaim allocated unused-space for the segments(预测segment回收空间)
Now I used segment advisor performs analysis on the segments and makes recommendations on how space can be reclaimed…
Script: Oracle Table/Tablespace/DB Growth Prediction(预测表/表空间/库增长)
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.
How to config hugepage on linux
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).
Check goldengate replicate Availability (检查OGG REPLICATE)
通过检查replicate进程确认OGG REPLICATE进程是否存活shell
