Tune this "contains" query in Oracle 11g EE 11.2.0.3.0

Question

I have a query like below. It runs for ever. The size of this table is not very big, it has around 30 millions rows. The owner column is very selective, and I've added "owner' column in the "filter by" clause of the domain index against description. Do you have any recommendation how I can tune this query? Any help would be greatly appreciated.
select count(*) from items s where contains(s.description, '%111%' ) > 0 and s.owner = 1234;
Thanks.

Answer 1

You need to use SDATA to access the owner column through the index. You may also get better performance on your wildcard searches by using a wordlist with attributes as shown below. Please see the demonstration below.
SCOTT@orcl_11gR2> create table items as
  2  select object_id as owner, object_name as description
  3  from   all_objects
  4  /
Table created.
SCOTT@orcl_11gR2> insert into items values (1234, 'A111B')
  2  /
1 row created.
SCOTT@orcl_11gR2> select count(*) from items
  2  /
  COUNT(*)
     75048
1 row selected.
SCOTT@orcl_11gR2> begin
  2    ctx_ddl.create_preference('mywordlist', 'BASIC_WORDLIST');
  3    ctx_ddl.set_attribute('mywordlist','PREFIX_INDEX','TRUE');
  4    ctx_ddl.set_attribute('mywordlist','PREFIX_MIN_LENGTH', 1);
  5    ctx_ddl.set_attribute('mywordlist','SUBSTRING_INDEX', 'YES');
  6    ctx_ddl.set_attribute('mywordlist', 'wildcard_maxterms', 50000) ;
  7  end;
  8  /
PL/SQL procedure successfully completed.
SCOTT@orcl_11gR2> create index items_idx
  2  on items (description)
  3  indextype is ctxsys.context
  4  filter by owner
  5  parameters ('wordlist  mywordlist')
  6  /
Index created.
SCOTT@orcl_11gR2> set autotrace on explain
SCOTT@orcl_11gR2> select count(*) from items
  2  where  contains (description, '%111% and (sdata (owner = 1234))') > 0
  3  /
  COUNT(*)
         1
1 row selected.
Execution Plan
Plan hash value: 1238254566
| Id  | Operation        | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT |           |     1 |    29 |    12   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE  |           |     1 |    29 |            |          |
|*  2 |   DOMAIN INDEX   | ITEMS_IDX |    39 |  1131 |     4   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - access("CTXSYS"."CONTAINS"("DESCRIPTION",'%111% and (sdata
              (owner = 1234))')>0)
Note
   - dynamic sampling used for this statement (level=2)
SCOTT@orcl_11gR2>