All entries for Monday 31 January 2005

Standby Db

1. dbms_logstdby.skip and skip_error. unskip, unskip_error
skip: do not apply SQL
skip_error: what to do if SQL apply occurs error

2. The alert.log give useful information.
For instance,

LOGSTDBY stmt: SYS.JOB$ (Oper=UPDATE)

It tell the operation is a DML, schema is SYS, table is JOB$

Note:

dba_jobs view use sys.job$ table to store actural data.

dbms_job.remove should be exeucte by job owner,i.e PERFSTAT, not SYS

Hongfeng Sun : 31 Jan 2005 14:00 |  Tags: Oracle |  Comments (0) |  Close comments |  Trackbacks (1) |  Report a problem

Ten tips for DBA

I copied ten tips from eweek.com

Make backup and recovery a top priority
Without good backup and recovery systems, DBAs can be guaranteed two things: IT disasters and unemployment. DBAs need to make data recovery their primary focus.

Lock out unused Oracle accounts
When you create a database, Oracle creates a number of ancillary accounts for a variety of Oracle Enterprise Manager (OEM) functions. Remember to lock out these unused accounts to outside users. If Oracle 9i is installed manually, then the ancillary accounts could remain open and create a hole in the system.

Put the production database in archive log mode
Running the database in archive log mode allows hot backups to be performed while the database is open and available. It also allows recovery of the database in the event of a failure. To avoid loss of critical data, an archive log is absolutely necessary.

Set privileges on data files
Unless the files are encrypted, someone knowledgeable in how Oracle stores data could access the files. Only those who need access to the data should be given privileges. In Unix, Oracle data files will allow anyone read/write access, unless DBAs set specific privileges.

Update: 10gR2 restrict access the datafiles. The normal mode is 640, which means only use belongs to oinstall group can read it.

Follow a prescribed set of standards when creating and administrating the database
Often a DBA will create a database without any standards for setting objects and creating a set of schemas. A lack of standards usually lands DBAs in a mess.

Don’t use new features before they’re ready for prime time(黄金时段）
A lot of the newest database features often need time to prove themselves. A good DBA is versed in new features but knows when and when not to use them. Any bugs in the new feature could cause the loss of valuable information.

Always be on the lookout for trouble
It’s important to set up a robust proactive monitoring program. For example, DBAs need to watch how much space they have free in the database and, as that number shrinks, they need to go in and make a planned change to increase the space.

Find a mentor
This is very important for new and midlevel DBAs, because the Oracle database encompasses so much technology. Find someone who is experienced and really knows what they are doing. Look for a mentor online, in DBA forums, or find one at work.

Read everything
Educate yourself as best as possible by keeping up with the latest technology and practices. This means knowing relational database technology, online transaction processing and data warehouse technology.

Trust nothing (at the outset)
Don’t trust everything you read at first glance. No two Oracle installations are the same.

Hongfeng Sun : 31 Jan 2005 10:38 |  Tags: Article Oracle Work |  Comments (0) |  Close comments |  Report a problem