Re: Extent Size on Table Performance Question

On Sun, 13 May 2007 17:07:21 -0500, "Dereck L. Dietz" <dietzdl_at_ameritech.net> wrote:

>I've been reading and came across a section about the impact of table extent
>size on performance.
>
>I'd like to apply what I read but before I go off and do it wrong I thought
>I'd post what I'm considering and see what observations/comments/suggestions
>anybody would like to share.
>
>Basic assumptions:
>
>1. Operating system I/O buffer size is 128K.
>2. NEXT extent size will be 128K.
>3. During table loads/reloads the table size will not grow to where it
>needs more than one more extent.
>4. The table's initial size will be 55,433 rows for a current size of
>7,737,465 bytes.
>5. Datawarehouse environment. No real data design/normalization.
>6. Oracle 10.2.03, Windows 2003 Server, 16GB memory.
>
>When I initially create the table, what would be the best option:
>
>1. Create it with an initial extent of 7,737,465 bytes allocating all the
>space it needs at once.
>
>2. Create it with an initial extent as a multiple of 128K but large
>enough to hold the initial rows.
>
>3. Just create it with an initial extent of 128K.
>

The best option would be
1 forget about this old myth
2 In a LMT: just create the table and stop worrying. Your extent clause will be recalculated in terms of tablespace extent sizes automagically anyway.
3 Consider migrating to a real operating system.

-- 
Sybrand Bakker
Senior Oracle DBA