Re: Oracle Myths

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
>
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>
>
Received on Wed May 15 2002 - 09:33:20 CDT