What's changed in Oracle 9i to make it easier to manage and what effect this has on your role as a dba and the business you support. Subscribe here
Introduction
9i Self Management
Simplified Operational Management
Oracle Enterprise Manager Enhancements
Summary
Further Reading/Other resources
This is the fifth article in the series examining the enhancements that have been made to the Oracle database in release 9i and the impact these have on business and technical issues. This month the focus is on the big improvements made to the manageability of Oracle databases which for some years have been getting bigger and more complex - and that's just the Oracle software!
If you want more information about the new features see the resources section which reviews books for further reading and contains links to information on Oracle Technology Network and other places.
Smartsoft also offer excellent instructor-led Oracle courses and SQL courses for developers and dbas at very competetive rates. Furthermore all our courses can be tailored to your exact needs at no extra cost to give even better value for money. See our Oracle courses section for more details.
New subscribers can read the previous Oracle 9i New Features articles here:
http://www.smart-soft.co.uk/Oracle/oracle9i-new-features-part1.htm
http://www.smart-soft.co.uk/Oracle/oracle9i-new-features-part2.htm
http://www.smart-soft.co.uk/Oracle/oracle-9i-backup-and-recovery.htm
http://www.smart-soft.co.uk/Oracle/oracle-9i-security-enhancements.htm
See here for articles on general performance
tuning
If you have any questions send them to us and we'll do our best to answer them straight away or, if not, in a future issue.
2. Oracle 9i Manageability Enhancements
For several years Oracle databases have been perceived to be more difficult to manage and therefore more expensive than Microsoft SQL Server databases. With Oracle 9i, Oracle have gone a long way to counter this perception by :-
Those are just a few of the changes made to improve manageability. We'll be looking at these and other changes, although not in great depth, but just enough to give you an idea of what's changed and what effect this might have on your role as an oracle dba.
The new features include self-managing undo (rollback) segments. No longer does the dba have to worry about the number and size of rollback segments to create and which transactions to assign to which rollback segment. All you have to do now is create an undo tablespace and let the Oracle database worry about contention and space allocation and utilization.
Tuning the PGA in Oracle 8i was effected by setting various parameters, but it was not easy to find the right values for the various parameters which meant that memory was often wasted due to over allocation. In Oracle9i the PGA can be left to the database to manage by setting pga_aggregate_target parameter to define the target memory allocation for the PGA and setting the workarea_size_policy parameter (at the system or session level) to enable dynamic tuning of the PGA.
Even though Oracle databases are now more autonomous, it doesn't mean that there is nothing left for the dba to do, however Oracle have made life easier for the dba by simplifying day to day operational tasks.
Probably the most significant change in this area is the introduction of a binary, server-based parameter file - known as a spfile. This enables parameter changes made whilst the database is running to be preserved when the database is shut down, which is especially important for changes made by performance tuning tools.
When making changes manually using the alter system command, the scope of the changes can be set to memory (changes are lost when the instance is shutdown), spfile (changes won't take effort until the instance is restarted, they are made only in the parameter file), or both (changes take effect immediately and are preserved when the instance shuts down).
Another significant change in Oracle 9i is the introduction of resumable space allocation. This means that any transaction that gets an error such as insufficient quota, max. extents reached, or unable to extend index/table/rollback segment can be suspended instead of being rolled-back. This enables the dba to fix the problem and then the transaction can resume from the point of interruption.
Ever wondered why your Oracle database couldn't create the associated file when a new tablespace was created and similarly delete the associated file when a tablespace was dropped ? Well, wonder no more, because with Oracle 9i it can and it can also create and delete the on-line redo log files automatically.
This new feature is enabled by setting the db_create_online_log_dest_n parameter(s) for log files which will also cause the database to create a copy of the control file in each of the directories specified by these parameters (n can be between 1 and 5), if the control_files parameter is not set. The data files associated with tablespaces are managed automatically if the db_create_file_dest parameter is set.
Many enhancements have also been made to Enterprise Manager in Oracle 9i to make it easier to use and more useful. These enhancements include the introduction of guided, expert problem diagnosis and resolution and the ability to have alerts generated automatically by the database when specified conditions are met which avoids the need for continual monitoring of the database in the hope of spotting problems.
Oracle has put a lot of effort into making Oracle 9i databases easier and therefor cheaper to manage, to reduce the "total cost of ownership" and to eliminate the perception that Oracle databases are difficult to manage.
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