RRC@node9 > create table a1(a varchar2(255))
  2  /

Table created.

Elapsed: 00:00:00.05
RRC@node9 > insert into a1(a) 
  2  select null from all_objects
  3  /

56295 rows created.

Elapsed: 00:00:00.44
RRC@node9 > create table a2(a varchar2(255) not null)
  2  /

Table created.

Elapsed: 00:00:00.02
RRC@node9 > insert into a2(a)         
  2  select object_name from all_objects where object_name is not null
  3  /

56296 rows created.

Elapsed: 00:00:00.39
RRC@node9 > commit
  2  /

Commit complete.

Elapsed: 00:00:00.06
RRC@node9 > create index a1_idx on a1(a)
  2  /

Index created.

Elapsed: 00:00:00.04
RRC@node9 > create index a2_idx on a2(a)
  2  /

Index created.

Elapsed: 00:00:00.51
RRC@node9 > exec
dbms_stats.gather_schema_stats(NULL,cascade=>true,granularity=>'ALL',options=>'GATHER
AUTO',estimate_percent=>dbms_stats.auto_sample_size);

PL/SQL procedure successfully completed.

Elapsed: 00:00:01.38
RRC@node9 > set autotrace traceonly explain
RRC@node9 > select count(*) from a1 where a like '%O%'
  2  /
Elapsed: 00:00:00.00

Execution Plan
----------------------------------------------------------
Plan hash value: 417082427

---------------------------------------------------------------------------
| Id  | Operation        | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------
|   0 | SELECT STATEMENT |        |     1 |   129 |     0   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE  |        |     1 |   129 |            |          |
|*  2 |   INDEX FULL SCAN| A1_IDX |     1 |   129 |     0   (0)| 00:00:01 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("A" IS NOT NULL AND "A" LIKE '%O%')

RRC@node9 > select count(*) from a2 where a like '%O%'
  2  /
Elapsed: 00:00:00.00

Execution Plan
----------------------------------------------------------
Plan hash value: 3851220615

---------------------------------------------------------------------------
| Id  | Operation          | Name | Rows  | Bytes | Cost (%CPU)| Time     |
---------------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |     1 |    26 |    68   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |      |     1 |    26 |            |          |
|*  2 |   TABLE ACCESS FULL| A2   |  2815 | 73190 |    68   (0)| 00:00:01 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("A" LIKE '%O%')

RRC@node9 > select count(*) from a1
  2  /
Elapsed: 00:00:00.00

Execution Plan
----------------------------------------------------------
Plan hash value: 2855827631

-------------------------------------------------------------------
| Id  | Operation          | Name | Rows  | Cost (%CPU)| Time     |
-------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |     1 |    25   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |      |     1 |            |          |
|   2 |   TABLE ACCESS FULL| A1   | 56295 |    25   (0)| 00:00:01 |
-------------------------------------------------------------------

RRC@node9 > select count(*) from a2
  2  /
Elapsed: 00:00:00.00

Execution Plan
----------------------------------------------------------
Plan hash value: 3851220615

-------------------------------------------------------------------
| Id  | Operation          | Name | Rows  | Cost (%CPU)| Time     |
-------------------------------------------------------------------
|   0 | SELECT STATEMENT   |      |     1 |    68   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE    |      |     1 |            |          |
|   2 |   TABLE ACCESS FULL| A2   | 56296 |    68   (0)| 00:00:01 |
-------------------------------------------------------------------

RRC@node9 >