Re: function index

Did you analyze the table after building the FB index? The FB index creates an invisible column in the table and unless the table is re-analyzed that column will have no statistics and the CBO will use column statistics defaults to calculate selectivity and estimated cardinality.

johan Eriksson wrote:
> Hi
>
> The database is 10.2 on RHEL 3.
>
> I have a table on which I have 2 indexes, one normal and one
> function-based.
>
> The different queries I run are
>
> select count(*) from t1 where username='user1';
> and
> select count(*) from t1 where lower(username)='user1';
>
> the index are created with
>
> create index f_t1_username on t1(lower(username));
> create index uq_t1_username on t1(username);
>

-- 
Regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com
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