Database Reference
In-Depth Information
Figure 11-2.
Index block with
OWNER
column repeated
We could factor the repeated
OWNER
column out of this, resulting in a block that looks more like Figure
11-3
.
Figure 11-3.
Index block with
OWNER
column factored out
In Figure
11-3
, the owner name appears once on the leaf blockānot once per repeated entry. We run the
following script, passing in the number 1, to re-create the scenario whereby the index is using compression on just the
leading column:
drop index t_idx;
create index t_idx on
t(owner,object_type,object_name)
compress &1;
analyze index t_idx validate structure;
insert into idx_stats
select 'compress &1', a.*
from index_stats a;