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Home -> Community -> Usenet -> c.d.o.misc -> Re: Large tables and Primary keys
Ian Downham wrote:
>
> Can anyone put me on the right track, please ?
>
> We have three Alphas running VMS 7.1 and ORACLE 7.3.2
> The system produces data locally as a result of recruitment operations
> (Home
> Shopping Catalog) and this is then transfered (near real time) to
> another
> Alpha for later use.
> This data is to be stored for upto two years.
> As part of the process a key is produced (enquiry_no) using a cyclic
> sequence,
> a company no.(1-8) and a nine digit sequential sequence number
>
> ie for company 4 on machine no. 2
>
> if the Alpha No. 2 sequence was 74
>
> Algorithm would use 744000000001 to produced a mod31 key of W19GEED1
>
> Alpha No. 1 - Sequences 63-69
> Alpha No. 2 - Sequences 70-76
> Alpha No. 3 - Sequences 77-83
>
> So Key ranges per machine would be 1. PXZFLJ9P - TDKMW3NR
> 2. TFVHGG4V - WYFPR1HW
> 3. X0PKCDZZ - ZGBSKZD0
>
> My problems is I don't know how indexes are built (internally) and so
> have
> no idea how find the correct value for PCTFREE when creating the Primary
> keys
> on the tables.
> Since the keys, when generated, will be in groups (as above) and will
> always
> be sequential do I have a problem with splitting index blocks if I get
> the
> PCTFREE wrong or could I just make it ZERO ?
> We will be, at some time, dumping the data to flat files then
> housekeeping /
> deleting the data (will this cause a problem with index space) ?
>
> Please put me straight, I'm totally confused.
>
> Thanks
>
> Ian (U.K)
>
> --
> to return e-mail remove nospam from address......
There is no such as thing as "updating" an index entry - it is removed and replaced...Thus PCTFREE for indexes should be very low (nearing 0)
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