ANBOB™

This latch comes into play when user processes are attempting to access or update the cached data dictionary values.

ORA-00600: internal error code, arguments: [ORA-00600: internal error code, arguments: [qkssao2s1], [], [], [], [], [], [], []

sql中如果使用了parallel hint 或是force parallel query 想并行查询的特性，如果那样做了就一定能保证 query optimizer选择并行的执行计划么？知道那样做实际上产生什么样的影响么？

ITL(Interested Transaction List ),The Oracle database engine locks the data modified by a transaction at the row level. To implement this feature every data block contains a list of all transactions that are modifying it. This list is commonly called interested transaction list (ITL).

Trail files are generated by both the original extract and the Data Pump (extract) process. Trail files are read by the Data Pump (extract) and Replicat (replicat) processes

Technically there is no schema level flashback feature […]

Every once in awhile it is useful to find out which ses […]

创建索引可以方便的给DB带来查询上的性能提升，但是DML时index的维护代价也是昂贵的。合理的创建索引，删除不必要的索引。

You can get the correct size of PGA using V$PGA_TARGET_ADVICE, dynamic performance view.

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 BULK COLLECT and Oracle FORALL are the new featu […]

I use goldengate(for oracle) to do a SCHEMA synchronize […]

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。

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 […]

1) Export the snapshots and then do a manual purge To p […]

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