Re: PCTFREE 1, Any advantage of using Pctfree 1

uday.v.lad_at_att.com wrote:
>
> Hi ! If you use PCTFREE = 1, SMON automatically coalsce your tablespace
> which otherwise be defragmented. Yes ! ORACLE also recommends using same.
>
> UDAY LAD
> AT&T
>
> SAM <u4immsm9_at_cpc25.usace.army.mil> wrote:
> > Is there any advantage of setting PCTFREE 1 instead of
> > using PCTFREE 0. in oracle 7.1/7.2.3
> >
> > Is it recomended by Oracle Corp. ?
> >

        I think you're mistaking PCTFREE with PCTINCREASE. If the default PCTINCREASE for a tablespace is zero, Oracle will not automatically coalesce
free space in that tablespace.

        PCTFREE determines the amount of empty space that Oracle will leave in each database block automatically. With PCTFREE 1, Oracle will remove a block
from the free list when one percent of the block is still empty; with PCTFREE 0,
Oracle will continue writing new rows to the block until it needs to insert a
row that would not fit entirely in that block.

        Keeping empty space in your data blocks is only important if you will be
doing UPDATES to the table in question. If you will be doing only inserts and
deletes to a particular table, you can progbably specify PCTFREE 0 safely.
Normally, I specify at least PCTFREE 1 -- even in Oracle 7.2. This is probably
superstitious behavior; I saw unusual behavior in Oracle 7.0 with PCTFREE 0 and
don't see any point in pushing it.

        Hope this helps.

-Brett Neumeier
neumebm_at_hpd.abbott.com Received on Wed Apr 16 1997 - 00:00:00 CDT