Index and column ordinal position
Posted on 2006-07-18
I recently added a new column to an existing table using
Alter table star12 add ID_GRP_RISK char(12)
The new field appears in last position when I run a desc on the table.
Now I need to create a new PK / Unique index using both the first column and the newly created one. Should column position be a concern.
I remember from my (old ;-) ) oracle days that column position might affect performances. I don't have the slightest idea if the version I use now (9i) has changed anything reagrding this column ordering.
Would a REORG be sufficient to get decent performances (after changing the unique index / primary key)
NB : dropping/creating the table to change its stucture was not an option.
Any comments welcome (I know I could find this kind of information on the net or simply browsing the KB .. I'm not lazy but my current mission does not leave me much time)