Re: How to handle large, frequent SQL*Loads?

On 31 Dec 1996 08:25:14 GMT, N Prabhakar <prabhs_at_po.pacific.net.sg> wrote:

>4. Create the table with a very large initial extent, so that you can
>prevent row chaining and migration, set PCTINCREASE to 0 (zero)

A large initial extent has nothing to do with chaining and migration. This is caused by updating an existing row, causing it to expand beyond the free space in the data block. This causes the rest of the row to be: continued elsewhere, leaving the rowid of the sequel ;-) in the initial block (chaining); or transfer of the row to a new location, also leaving the rowid of the new location in the initial block (migrating).
In my opinion this cannot be done in an import session. To prevent chaining and/or migrating (during normal use), set the pctfree higher thus leaving enough space in each extent for the row to grow. There is no recomended size, as this must be determined on a case-to-case basis.
Pctincrease doesn't have any effect on an import either, because it sets the increament factor for next extents. The goal of this parameter is to reserve enough (contiguous) space in the datase, thus avoiding fragmentation.

Since import imports each table after each other, you can't have fragmentation, nor chaining or migration. My $0,02 Received on Sun Jan 05 1997 - 00:00:00 CST