Re: Oracle Myths

Joe E O wrote:

> Niall,
> I have been doing Oracle Database Administration for about two years
> (transitioning from Sybase and MS SQL) and have found that these items are
> more prevalent and pervasive than myth - they have become truth and accepted
> as "best practices" by IT management and many DBAs.
>
> I have had my competence question on the "Store Segments in one Extent"
> issue - I wasn't spending time sizing each object to fit in one extent. I am
> currently interviewing and "failed" the technical part of an interview
> because my responses relating to the "high buffer cache hit ratios are
> always better" and "set Pct increase to 1% to avoid tablespace
> fragmentation" and the "separate tables and indexes for better performance
> reasons"
>
> Very frustrating...
>
> Joe O'Brien
>
> "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message
> news:3ce21b71$0$8510$ed9e5944_at_reading.news.pipex.net...
> > Suggested list to be added to, deleted from etc
> >
> > Store your segments in one extent for optimum performance.
> > Space in an index is never reused.
> > Full table scans are always bad: use the index.
> > Seperate tables and indexes for performance reasons.
> > You should always backup the online redo logs to avoid data loss.
> > Buffer cache hit ratio should be as high as possible preferably greater
> than
> > 90%.(from the java tool we use developed in house)
> > Library Cache hit ratio should be greater than 99% if it isn't increase
> the
> > size of the shared pool.(ditto!)
> > Smallest table should be the driving table for hash joins.
> > PCTIncrease should be as small as possible but non-zero to minimize
> > tablespace fragmentation.1% is a good value (from my OCP course notes
> though
> > not necessarily given by the tutor!)
> >
> > --
> > Niall Litchfield
> > Oracle DBA
> > Audit Commission UK
> > *****************************************
> > Please include version and platform
> > and SQL where applicable
> > It makes life easier and increases the
> > likelihood of a good answer
> >
> > ******************************************
> >
> >

I can understand this and no doubt others here can too. I have had more than a few interviews where I found myself correcting the information that the interviewers believed to be true. The only saving grace, as I teach Oracle, is that they perceive me as knowing more than they do. Without that ... I am sure I'd have been excused and never contacted again.

Daniel Morgan Received on Wed May 15 2002 - 11:10:25 CDT