[AccessD] Compression Interesting read - part 2

Salakhetdinov Shamil mcp2004 at mail.ru
Fri Dec 9 03:26:35 CST 2011


Hi Stuart --

Thank you for your question.

AFAIU MS SQL page compression feature substitutes all the duplicate entries in data records columns of  a DB file page by one/two/... bytes long references to "dictionary" area located on the same page.
By "duplicate entries" are meant not only full length columns' values but also their  values' leading parts...
Please read the articles/blog entries JC referred in his postings for details.

Please correct me if you'll find I'm wrong.

Thank you.

-- Shamil

P.S.  Stuart, please note I've written "using natural keys for *OLAP* systems" - I have no any intentions in re-starting "surrogate vs. natural keys" generic discussion covering OLTP systems - I'm *currently* strong advocate of using surrogate keys in OLTP systems.... 


09 декабря 2011, 03:27 от "Stuart McLachlan" <stuart at lexacorp.com.pg>:
> Sorry, you've lost me completely there.  Would you care to explain how data page
> compression has any bearing on natural v surrogate keys?
> 
> --
> Stuart
> 
> On 9 Dec 2011 at 2:54, Salakhetdinov Shamil wrote:
> 
> > Hi John --
> >
> > Yes, this PAGE compression feature makes using natural keys for OLAP
> > systems more preferable than using surrogate keys..
> >
> > Thank you.
> >
> > -- Shamil.
> >
> 
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