Re: function index
- From: Wolfgang Breitling <breitliw@xxxxxxxxxxxxx>
- To: johan.eriksson@xxxxxxxxxxxx
- Date: Mon, 23 Jan 2006 15:17:49 -0700
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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- From: johan Eriksson
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- » Re: function index
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
- function index
- From: johan Eriksson