Re: Help HASH clusters oracle 7
Date: Wed, 30 Jun 1999 10:48:50 -0300
Message-ID: <34qe3.168908$r_1.40403114_at_newscontent-02.sprint.ca>
To make good hash cluster you need to choose the column with big
selectivity.
This column will be used later as assess key to table.
Usualy the best are ID columns. This are unique.
Sample:
If you have table Streets
ID Name
------ -----------
1 Abbey 2 Aglington
.....
20000000 Yonge
The good hash key will ID
create cluster Streets_HC (ID number)
size 40 -- set average size of full row (all colums) in bytes or a little
bit more.
hashkeys 200001000 --a little bit more
hash is ID;
- add table to cluster create table Streets (id number, Name char(30)) cluster Streets_HC (ID);
Regards,
Mark
Seigmund Akinwande Johnson <asjohns_at_midway.uchicago.edu> wrote in message
news:FE3ywG.DwC_at_midway.uchicago.edu...
> All:
>
> Who has ever worked with this and what are the issues to consider,
> I have a 20 Million static record table, that requires fast access
> Any help would be fine
>
> --
> Developer Preserve Project
> BSDIS
> 773-834-2652
>
>
Received on Wed Jun 30 1999 - 15:48:50 CEST