Re: Index Corruption ??

From: Thomas Kyte <tkyte_at_us.oracle.com>
Date: Mon, 21 Sep 1998 19:53:39 GMT
Message-ID: <360face6.24073545@192.86.155.100>

A copy of this was sent to stuco_at_mailcity.com (if that email address didn't require changing) On Mon, 21 Sep 1998 19:28:59 GMT, you wrote:

>I wanted to check the validity of something an old Oracle guru once told me.
>
>He says, "... in very large database indexing, be sure that your MAXEXTENTS
>parameter is not more than what the index tablespace will actually hold when
>full. This will corrupt your indexes based on how the b-tree indexing works"
>
> Example: 100MB Index Tablespace
> 10 MB Initial
> 5 MB Next
> 19 MAXEXTENTS (not 255 or 999)
>
>Is this true or is it just bunk?!?! If it is true, why? I'm trying to set my

bunk. also, in a 100m tablespace you won't get 100m -- there is overhead for segment management and such

SQL> create tablespace demo datafile '/user2/ora7321/oradata/o7321/demo.dbf' size 10m;

Tablespace created.

SQL>
SQL> create table demo_tbl ( x int ) tablespace users;

Table created.

SQL> create index demo_idx on demo_tbl(x)   2 storage ( initial 1m next 1m pctincrease 0 minextents 10 ) tablespace demo; create index demo_idx on demo_tbl(x)

                         *

ERROR at line 1:
ORA-01659: unable to allocate MINEXTENTS beyond 9 in tablespace DEMO

So, it created the index with 9 extents because it could not make that 10'th one in there...

>maxextents and I'm wondering how much calculation needs to go into this
>process.
>
>Thanks again, People of the Oracle Underworld!
>
>Stuart Cowen
>Paladin Consulting - Dallas
>
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Thomas Kyte
tkyte_at_us.oracle.com
Oracle Government
Herndon VA

--
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---

Opinions are mine and do not necessarily reflect those of Oracle Corporation  

Anti-Anti Spam Msg: if you want an answer emailed to you, you have to make it easy to get email to you. Any bounced email will be treated the same way i treat SPAM-- I delete it. Received on Mon Sep 21 1998 - 14:53:39 CDT