Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

CHAPTER 13 ■ PARTITIONING 599
implementation that provides for full data availability, even during the partition operations.
In that manner, we can measure the same operations using the different techniques and compare
them. Our expected outcome will be that the first approach will consume fewer database
resources and, therefore, perform “faster” but will incur a measurable period of “downtime.”
The second approach, while consuming more resources and perhaps taking longer overall,
will not incur downtime. As far as the end users are concerned, their ability to work never
ceased. They might have been processing a bit slower (since we were competing with them
for resources), but they were still processing, and they never stopped.
So, if we take the earlier example, but also create an empty FY_2005 table like FY_2004, and
a full FY_2007 table like FY_2006, we can measure the differences between the index rebuild
approaches, starting first with the “less available approach”:
exec runStats_pkg.rs_start;
alter table partitioned exchange partition fy_2004
with table fy_2004 including indexes without validation;
alter table partitioned drop partition fy_2004;
alter table partitioned add partition fy_2006
values less than ( to_date('01-jan-2007','dd-mon-yyyy') );
alter table partitioned exchange partition fy_2006
with table fy_2006 including indexes without validation;
alter index partitioned_idx_global rebuild;
exec runStats_pkg.rs_middle;
Here is the highly available UPDATE GLOBAL INDEXES approach:
alter table partitioned exchange partition fy_2005
with table fy_2005 including indexes without validation
update global indexes;
alter table partitioned drop partition fy_2005
update global indexes;
alter table partitioned add partition fy_2007
values less than ( to_date('01-jan-2008','dd-mon-yyyy') );
alter table partitioned exchange partition fy_2007
with table fy_2007 including indexes without validation
update global indexes;
exec runStats_pkg.rs_stop;