Re: Q:Table Fragmentation. How do I reduce it?

On Tue, 17 Mar 1998 17:10:45 +0800, Connor McDonald <mcdonald.connor.cs_at_bhp.com.au> wrote:

Hi Connor,
why fragmentation does not affect performance? Everybody, every book claims that fragmantation is a performance penalty.

>Rao Uppuluri wrote:
>>
>> Hi all
>>
>> Setup: Oracle 7.3.2.3 on HP-UX 10.20
>>
>> I have a table(s) with lot of extents allocated to it. These extents are
>> small extents. The extents allocated are not all next to each other.
>> Some are but not all. If I drop the table and recreate it, do I get a
>> lot of "free space fragmentation"? How do I reduce the fragmentation of
>> the table? Do I have to export and import the whole tablespace?? ( I have
>> many of these tables with lot of extents allocated to them in the tablespace)
>>
>> Thanx in ADvance
>>
>> Rao Uppuluri
>> (uppuluri_at_XidtX.net -- Please remove X's)
>
>Also worthy of note that in a normal (ie multi-user) environment then as
>a general rule, lots of extents will NOT affect performance. The
>popular belief that the performance of one extent is always better than
>many is a myth...
>
>This is not to say the exp/imp will not assist. Unloading and reloading
>the data has many benefits in terms of better packing the rows etc
>etc...But exp compress=y OR exp compress=n will give you the same
>benefits...
>--
>==========================================
>Connor McDonald
>BHP Information Technology
>Perth, Western Australia
>"These views mine not BHP..etc etc"
>
>"The only difference between me and a madman is that I am not mad."

--

Regards

Matthias Gresz    :-)

GreMa_at_T-online.de