關於分區表的性能問題

關於分區表的性能問題

create table test1(test_id number(9),id number(9),log_time date)
partition by range(log_time)
(partition t1_01 values less than (to_date('2004-02-01','yyyy-mm-dd')),
partition t1_02 values less than (to_date('2004-03-01','yyyy-mm-dd')),
partition t1_03 values less than (to_date('2004-04-01','yyyy-mm-dd')),
partition t1_04 values less than (to_date('2004-05-01','yyyy-mm-dd')),
partition t1_05 values less than (to_date('2004-06-01','yyyy-mm-dd')),
partition t1_06 values less than (to_date('2004-07-01','yyyy-mm-dd')),
partition t1_07 values less than (to_date('2004-08-01','yyyy-mm-dd')),
partition t1_08 values less than (to_date('2004-09-01','yyyy-mm-dd')),
partition t1_09 values less than (to_date('2004-10-01','yyyy-mm-dd')),
partition t1_10 values less than (to_date('2004-11-01','yyyy-mm-dd')),
partition t1_11 values less than (to_date('2004-12-01','yyyy-mm-dd')),
partition t1_12 values less than (to_date('2005-01-01','yyyy-mm-dd')));

create table test2(test_id number(9),id number(9),log_time date);

create sequence seq_t1;
create sequence seq_t2;

create index idx_test1_logtime on test1(log_time) local;
create index idx_test1_testid on test1(test_id) local;
create index idx_test1_id on test1(id) local;

create index idx_test2_logtime on test2(log_time);
create index idx_test2_testid on test2(test_id);
create index idx_test2_id on test2(id);

關於分區表與非分區表的測試
begin
for i in 1 .. 1000 loop
for j in 1 .. 12 loop
for k in 1 .. 28 loop
insert into test1 values(seq_t1.nextval,i,to_date('2004-'||to_char(j)||'-'||to_char(k),'yyyy-mm-dd'));
end loop;
end loop;
end loop;
end;
/
begin
for i in 1 .. 1000 loop
for j in 1 .. 12 loop
for k in 1 .. 28 loop
insert into test2 values(seq_t2.nextval,i,to_date('2004-'||to_char(j)||'-'||to_char(k),'yyyy-mm-dd'));
end loop;
end loop;
end loop;
end;
/

SQL> select count(*) from test1;

COUNT(*)
----------
336000

Elapsed: 00:00:00.02

Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
1104 consistent gets
0 physical reads
0 redo size
394 bytes sent via SQL*Net to client
508 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed

SQL> select count(*) from test2;

COUNT(*)
----------
336000

Elapsed: 00:00:00.02

Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
1067 consistent gets
0 physical reads
0 redo size
394 bytes sent via SQL*Net to client
508 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed

統計顯示,分區表在全表掃描時將比非分區表須要更多的邏輯讀

SQL> select count(*) from test1 where test_id = 1000;

COUNT(*)
----------
1

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

SQL> select count(*) from test2 where test_id = 337000;

COUNT(*)
----------
1

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

在沒有與分區字段組合查詢時,分區表須要更多的邏輯讀

SQL> select count(*) 
2 from test1 
3 where id = 1000 
4 and log_time between to_date('2004-11-01','yyyy-mm-dd') and to_date('2004-11-30 23:59:59','yyyy-mm-dd hh24:mi:ss');

COUNT(*)
----------
28

Elapsed: 00:00:00.01

Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
3 consistent gets
0 physical reads
0 redo size
393 bytes sent via SQL*Net to client
508 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)

SQL> select count(*) 
2 from test2
3 where id = 1000 
4 and log_time between to_date('2004-11-01','yyyy-mm-dd') and to_date('2004-11-30 23:59:59','yyyy-mm-dd hh24:mi:ss');

COUNT(*)
----------
28

Elapsed: 00:00:00.00

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

與分區字段組合查詢時,分區表比非分區表有更好的性能優點