组合索引,索引内过滤

oadb01:/home/oracle/sbin> sqlplus query/query

SQL*Plus: Release 11.2.0.4.0 Production on 星期二 10月 20 11:16:19 2015

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

BEGIN
DBMS_STATS.GATHER_TABLE_STATS(ownname          => 'SCOTT',
tabname          => 'DEPT',
estimate_percent => 30,
method_opt       => 'for all columns size repeat',
no_invalidate    => FALSE,
degree           => 8,
cascade          => TRUE);
END;
/

create table test(zipcode int,lastname varchar2(20),address varchar2(100),flag int);

begin
for i in  1..1000000
loop
insert into people values(i,i||'aa',i||'bb');
end loop;
end;

模拟数据:

begin
for i in  1..100
loop
insert into people values(9999,'zhao','zhongjun');
end loop;
end;

BEGIN
DBMS_STATS.GATHER_TABLE_STATS(ownname          => 'QUERY',
tabname          => 'PEOPLE',
estimate_percent => 100,
method_opt       => 'for all columns size repeat',
no_invalidate    => FALSE,
degree           => 8,
cascade          => TRUE);
END;

SQL> create index p_idx1 on people(zipcode);

Index created.

SQL> select count(*) from test;

COUNT(*)
----------
3100100

SQL>  select count(*) from test where zipcode=9999;

COUNT(*)
----------
100003

SQL> select * from test where zipcode=9999 and lastname like '%aa%';

ZIPCODE LASTNAME		ADDRESS 	 FLAG
---------- -------------------- ---------- ----------
9999 9999aa		9999bb		 9999
9999 9999aa		9999bb		 9999
9999 9999aa		9999bb		 9999
9999 144aa66		1bb55		    1
9999 244aa66		2bb55		    2
9999 344aa66		3bb55		    3
9999 444aa66		4bb55		    4
9999 544aa66		5bb55		    5
9999 644aa66		6bb55		    6
9999 744aa66		7bb55		    7
9999 844aa66		8bb55		    8

ZIPCODE LASTNAME		ADDRESS 	 FLAG
---------- -------------------- ---------- ----------
9999 944aa66		9bb55		    9
9999 1044aa66		10bb55		   10

13 rows selected.

BEGIN
DBMS_STATS.GATHER_TABLE_STATS(ownname          => 'test',
tabname          => 'test',
estimate_percent => 100,
method_opt       => 'for all columns size repeat',
no_invalidate    => FALSE,
degree           => 8,
cascade          => TRUE);
END;

SQL>  select * from test where zipcode=9999 and lastname like '%aa%';

13 rows selected.

Execution Plan
----------------------------------------------------------
Plan hash value: 4199073991

--------------------------------------------------------------------------------------
| Id  | Operation		    | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT	    |	     |	   1 |	  28 |	   7   (0)| 00:00:01 |
|*  1 |  TABLE ACCESS BY INDEX ROWID| TEST   |	   1 |	  28 |	   7   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN	    | P_IDX1 |	   3 |	     |	   3   (0)| 00:00:01 |
--------------------------------------------------------------------------------------

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

1 - filter("LASTNAME" LIKE '%aa%' AND "LASTNAME" IS NOT NULL)
2 - access("ZIPCODE"=9999)

Statistics
----------------------------------------------------------
0  recursive calls
0  db block gets
596  consistent gets
0  physical reads
0  redo size
1057  bytes sent via SQL*Net to client
519  bytes received via SQL*Net from client
2  SQL*Net roundtrips to/from client
0  sorts (memory)
0  sorts (disk)
13  rows processed

SQL>  select * from test where zipcode=9999 and lastname like '%aa%';

13 rows selected.

Execution Plan
----------------------------------------------------------
Plan hash value: 1934812006

--------------------------------------------------------------------------------------
| Id  | Operation		    | Name   | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT	    |	     |	   1 |	  28 |	   4   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| TEST   |	   1 |	  28 |	   4   (0)| 00:00:01 |
|*  2 |   INDEX RANGE SCAN	    | P_IDX2 |	   1 |	     |	   3   (0)| 00:00:01 |
--------------------------------------------------------------------------------------

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

2 - access("ZIPCODE"=9999)
filter("LASTNAME" LIKE '%aa%' AND "LASTNAME" IS NOT NULL)

Statistics
----------------------------------------------------------
0  recursive calls
0  db block gets
288  consistent gets
0  physical reads
0  redo size
1127  bytes sent via SQL*Net to client
519  bytes received via SQL*Net from client
2  SQL*Net roundtrips to/from client
0  sorts (memory)
0  sorts (disk)
13  rows processed