Sunday, December 09, 2007

Hiring DBAs based on certification

There was a question in the OTN database forum recently which said:

" Can any one advise me? I have joined a company as new senior dba.

i am not understanding what shall be done at beginning?

Can anybody advice me how to check all the database and what to do in the beginning ?

I have been reading all the stuff,documents fr. a week?"

The same poster also said:

" I have all th knowledge of oracle,I am ocp certified.

But fearing at the beginning.

how to proceede as this is my first job as a dba."

This is what can happen when a company hires someone for a position like "senior DBA" just based on some papers called certifications.

How he claims he has "all the knowledge of oracle" just by getting an OCP certification is another story.

Thursday, December 06, 2007

Consolidating oraInventories

I have always had trouble with dealing with multiple oraInventories and multiple oraInst.loc files in a server.

If there are lots of people installing products in a server or if you are handed an environment which is in such a mess it is a big trouble to get things tidied up (if the installer people used a central inventory instead of each one using their own inventories, you a re lucky).

You need to know which oraInst.loc points to which oraInventory and which products and versions are in that inventory. You need to put the right oraInst.loc in place in order to install a patchset or a patch. Or you need a way to make the central inventory know about all Oracle homes which exist but which are not in the inventory.

In such situations Oracle Universal Installer 10.2 comes to the rescue. There is a Metalink note I have just realized which is 438133.1. The note explains how to consolidate multiple Oracle homes in one central inventory. There is a new option of the installer in 10.2 which is -attachHome. Using a 10.2 installer and this option you can get all your homes included in the central inventory.

./runInstaller -silent -attachHome ORACLE_HOME=<home you want to add> ORACLE_HOME_NAME=<unique home name>

The steps are clearly explained in the note which basically are; using a 10.2 universal installer, setting oraInst.loc to point to the inventory which you want to use to consolidate everything in, setting $ORACLE_HOME to the home you want to include and running the installer with the -attachHome option.

This works for 9i and 10G.

Optimizer blog

As I have learnt from Greg Rahn's blog Structured Data, the people behind the optimizer started blogging. In their first technical post they talk about bind peeking in 11G. I think we will see lots of examples and explanations about the optimizer in there. Their blog is here.

Wednesday, December 05, 2007

Hard Disk Reference

There was a reference to a site about the hard disk a few days ago in the oracle-l list from Ranko Mosic. I have gone through half of it for now, I can say the referenced pages are a great guide for understanding the basics of the hard disk, its parts, inner workings, etc... Trying to tune I/O without knowing about the hard disk basics can lead a DBA to the wrong path easily, this site is a must read in my opinion.