Performance issue on Select ...like

Question

Hi all,
we have Oracle 9206, and when starting the following SQL statement, we have a important runtime, and we have a index on those fields, but when we use LIKE, we have a full table scan. My question is about the second SQL statement BETWEEN (or >= <= operators) if we can use it instead of LIKE, please advise. I've already export/import the table and the statistics are OK, and I've setup the Histogram on involved fields on the select but with out success, the runtime for the SELECT using LIKE is about 30/40 seconds it's not normal and the table include more than 1 million of entries.
1. Select Partner from tab1 where field1 like 'VAN%' and field2 like 'K%';
2. Select Partner from tab1 where field1 >= 'VAN' and field2 >='K';
Regards,
Aziz K.

Answer 1

Why not test yourself ?
SQL> create table p_tbl (partner varchar2(10), field1 varchar2(10), field2 varchar2(10));
Table created.
SQL>
SQL> begin
  2  for i in 1..1000000 loop
  3      insert into p_tbl values (trunc(i/100),dbms_random.string('U',10),dbms_random.string('U',10));
  4  end loop;
  5  end;
  6  /
PL/SQL procedure successfully completed.
SQL>
SQL> create index idx_p_tbl on p_tbl (field1,field2);
Index created.
SQL>
SQL> exec dbms_stats.gather_table_stats(user,'P_TBL', cascade=>true)
PL/SQL procedure successfully completed.
SQL>
SQL> set timi on
SQL> select partner, field1, field2
  2  from p_tbl
3 where field1 like 'VAN%'
4 and field2 like 'K%';
PARTNER    FIELD1     FIELD2
7453       VANMKBIEZC KYDQHLZQHM
1694       VANNBPJNQQ KTVUNNUGUR
3408       VANQNSYBQP KSSYLCQKZE
4324       VANSUKOECK KAJAYLSMLG
Elapsed: 00:00:00.04
SQL>
SQL> select partner, field1, field2
  2  from p_tbl
3 where field1 between 'VAN' and 'VANZZZZZZZ'
4 and field2 between 'K' and 'KZZZZZZZZZ';
PARTNER    FIELD1     FIELD2
7453       VANMKBIEZC KYDQHLZQHM
1694       VANNBPJNQQ KTVUNNUGUR
3408       VANQNSYBQP KSSYLCQKZE
4324       VANSUKOECK KAJAYLSMLG
Elapsed: 00:00:00.03
SQL> set timi off
SQL> explain plan for select partner, field1, field2
  2  from p_tbl
  3  where field1 like 'VAN%'
  4  and field2 like 'K%';
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
Plan hash value: 500196574
| Id  | Operation                   | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
PLAN_TABLE_OUTPUT
|   0 | SELECT STATEMENT            |           |     1 |    26 |     4   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| P_TBL     |     1 |    26 |     4   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IDX_P_TBL |     1 |       |     3   (0)| 00:00:01 |
PLAN_TABLE_OUTPUT
Predicate Information (identified by operation id):
   2 - access("FIELD1" LIKE 'VAN%' AND "FIELD2" LIKE 'K%')
       filter("FIELD1" LIKE 'VAN%' AND "FIELD2" LIKE 'K%')
15 rows selected.
SQL> explain plan for select partner, field1, field2  
  2  from p_tbl
  3  where field1 between 'VAN' and 'VANZZZZZZZ' 
  4  and field2 between 'K' and 'KZZZZZZZZZ';
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
Plan hash value: 500196574
| Id  | Operation                   | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
PLAN_TABLE_OUTPUT
|   0 | SELECT STATEMENT            |           |     1 |    26 |     4   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| P_TBL     |     1 |    26 |     4   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN          | IDX_P_TBL |     1 |       |     3   (0)| 00:00:01 |
PLAN_TABLE_OUTPUT
Predicate Information (identified by operation id):
   2 - access("FIELD1">='VAN' AND "FIELD2">='K' AND "FIELD1"<='VANZZZZZZZ' AND
              "FIELD2"<='KZZZZZZZZZ')
       filter("FIELD2"<='KZZZZZZZZZ' AND "FIELD2">='K')
16 rows selected.Conclusion ? LIKE or BETWEEN seems to be same in my case.
Nicolas.