RE: precalculating table size

Please don't see any sarcastic meaning in my answer, but you should read carefully the "Data blocks, extents and segments" chapter of the Oracle Concepts manual vol.1 which explains very clearly ( IMHO ) how space is allocated to objects.

Space usage will also vary with the DB_BLOCK size you set on your machine. And I'm really surprised that the setting of PCTFREE has no effect. Have a look at DBA_EXTENTS to see how many extents / blocks /bytes are allocated to your table.

If you want to know more, feel free to email me directly ( I was just about to read the aforementionned chapter, so things will be pinned in my small SGA ;-). HTH
> ----------
> From: Andreas Jung[SMTP:ajung_at_sz-sb.de]
> Reply To: ORACLE-L_at_fatcity.com
> Sent: Wednesday, May 31, 2000 13:57
> To: Multiple recipients of list ORACLE-L
> Subject: precalculating table size
>
> Regard the following table:
>
> (docnum number(10,0), contents varchar2(4000) storage(initial 4k next 4k
> pctincrease 0)
>
> I inserted 1000 rows into the table - each with a contents column of exact
> 1000 bytes.
> I expected a complete size of the table to be about 1.0 - 1.1 MB. Looking
> at the segment
> this table allocates 1.5 MB on my system. Were is Oracle wasting the space
> ?!
> Or how can reduce this wasting of space ? The table is only used for
> inserts.
> Playing with PCTFREE and PCTUSED had also no effect.
>
> Any ideas ?
>
> Andreas Jung
>
>
> --
> Author: Andreas Jung
> INET: ajung_at_sz-sb.de
>
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Received on Wed May 31 2000 - 10:03:15 CDT