前言
前段时间报表数据库上有条insert sql语句，插入的大量数据，执行非常慢，需要对其进行分析优化。
分析步骤是在：ARCHIVE与NOARCHIVE模式下进行。
测试场景: 分别对表的常规插入，表在append插入，表在append + parallel插入进行性能测试，得出结果。
环境准备
| 数据库版本 | 基础表 | nologging表 | logging表 |
|---|---|---|---|
| Oracle 11g | T1 | T2 | T3 |
#创建T1,T2,T3表
create table t1 as select * from dba_objects;
create table t2 as select * from dba_objects where 1=2;
create table t3 as select * from dba_objects where 1=2;
#往T1表插入数据
SQL> insert into t1 select * from t1;
72813 rows created.
SQL> /
145626 rows created.
SQL> /
291252 rows created.
SQL> select count(*) from t1;
COUNT(*)
----------
582504
#设置T2表为nologging属性
SQL> alter table t2 nologging;
Table altered.数据库处于ARCHIVE时
常规插入
nologging 表T2
SQL> insert into t2 select * from t1;
commit;
582824 rows created.
Execution Plan
----------------------------------------------------------
Plan hash value: 3617692013
---------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------
| 0 | INSERT STATEMENT | | 582K| 53M| 1455 (2)| 00:00:18 |
| 1 | LOAD TABLE CONVENTIONAL | T2 | | | | |
| 2 | TABLE ACCESS FULL | T1 | 582K| 53M| 1455 (2)| 00:00:18 |
---------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
3345 recursive calls
46879 db block gets
27878 consistent gets
8269 physical reads
67752144 redo size
838 bytes sent via SQL*Net to client
784 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
582824 rows processed
SQL>
Commit complete. 耗费：67752144 redo size
logging 表T3
SQL> insert into t3 select * from t1;
commit;
582824 rows created.
Execution Plan
----------------------------------------------------------
Plan hash value: 3617692013
---------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------
| 0 | INSERT STATEMENT | | 582K| 53M| 1455 (2)| 00:00:18 |
| 1 | LOAD TABLE CONVENTIONAL | T3 | | | | |
| 2 | TABLE ACCESS FULL | T1 | 582K| 53M| 1455 (2)| 00:00:18 |
---------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
2860 recursive calls
46875 db block gets
27811 consistent gets
1 physical reads
67875992 redo size
829 bytes sent via SQL*Net to client
784 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed
SQL>
Commit complete.耗费：67875992 redo size
append 插入
nologging 表T2
SQL> insert /*+ append */ into t2 select * from t1;
commit;
582824 rows created.
Execution Plan
----------------------------------------------------------
ERROR:
ORA-12838: cannot read/modify an object after modifying it in parallel
SP2-0612: Error generating AUTOTRACE EXPLAIN report
Statistics
----------------------------------------------------------
2627 recursive calls
9324 db block gets
8832 consistent gets
0 physical reads
143436 redo size
824 bytes sent via SQL*Net to client
798 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：143436 redo size
logging 表T3
SQL> insert /*+ append */ into t3 select * from t1;
582824 rows created.
Execution Plan
----------------------------------------------------------
ERROR:
ORA-12838: cannot read/modify an object after modifying it in parallel
SP2-0612: Error generating AUTOTRACE EXPLAIN report
Statistics
----------------------------------------------------------
2627 recursive calls
9327 db block gets
8832 consistent gets
0 physical reads
68384900 redo size
822 bytes sent via SQL*Net to client
797 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：68384900 redo size
parallel + append 插入
nologging 表T2
SQL> alter session enable parallel dml;
insert /*+ append parallel(2) */ into t2 select * from t1;
commit;
Session altered.
SQL>
582824 rows created.
Execution Plan
----------------------------------------------------------
ERROR:
ORA-12838: cannot read/modify an object after modifying it in parallel
SP2-0612: Error generating AUTOTRACE EXPLAIN report
Statistics
----------------------------------------------------------
52 recursive calls
32 db block gets
19 consistent gets
0 physical reads
21916 redo size
824 bytes sent via SQL*Net to client
809 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：21916 redo size
logging 表T3
SQL> alter session enable parallel dml;
insert /*+ append parallel(2)*/ into t3 select * from t1;
commit;
Session altered.
SQL>
582824 rows created.
Execution Plan
----------------------------------------------------------
ERROR:
ORA-12838: cannot read/modify an object after modifying it in parallel
SP2-0612: Error generating AUTOTRACE EXPLAIN report
Statistics
----------------------------------------------------------
50 recursive calls
33 db block gets
20 consistent gets
0 physical reads
21308 redo size
824 bytes sent via SQL*Net to client
808 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：21308 redo size
数据库处于NOARCHIVE时
常规插入
nologging 表T2
Execution Plan
----------------------------------------------------------
Plan hash value: 3617692013
---------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------
| 0 | INSERT STATEMENT | | 582K| 53M| 1455 (2)| 00:00:18 |
| 1 | LOAD TABLE CONVENTIONAL | T2 | | | | |
| 2 | TABLE ACCESS FULL | T1 | 582K| 53M| 1455 (2)| 00:00:18 |
---------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
2538 recursive calls
46869 db block gets
27796 consistent gets
8266 physical reads
67754744 redo size
824 bytes sent via SQL*Net to client
784 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：67754744 redo size
logging 表T3
Execution Plan
----------------------------------------------------------
Plan hash value: 3617692013
---------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------------
| 0 | INSERT STATEMENT | | 582K| 53M| 1455 (2)| 00:00:18 |
| 1 | LOAD TABLE CONVENTIONAL | T3 | | | | |
| 2 | TABLE ACCESS FULL | T1 | 582K| 53M| 1455 (2)| 00:00:18 |
---------------------------------------------------------------------------------
Statistics
----------------------------------------------------------
2593 recursive calls
46873 db block gets
27800 consistent gets
1600 physical reads
67757328 redo size
824 bytes sent via SQL*Net to client
784 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
3 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：67757328 redo size
append 插入
nologging 表T2
Statistics
----------------------------------------------------------
2627 recursive calls
9324 db block gets
8832 consistent gets
2993 physical reads
143480 redo size
822 bytes sent via SQL*Net to client
798 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：143480 redo size
logging 表T3
Statistics
----------------------------------------------------------
2627 recursive calls
9327 db block gets
8832 consistent gets
0 physical reads
143420 redo size
821 bytes sent via SQL*Net to client
798 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：143420 redo size
parallel + append 插入
nologging 表T2
Statistics
----------------------------------------------------------
50 recursive calls
32 db block gets
21 consistent gets
0 physical reads
21896 redo size
823 bytes sent via SQL*Net to client
810 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：21896 redo size
logging 表T3
Statistics
----------------------------------------------------------
50 recursive calls
33 db block gets
20 consistent gets
0 physical reads
21896 redo size
821 bytes sent via SQL*Net to client
809 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
582824 rows processed耗费：21896 redo size
综合比较
| 属性 | 表名 | 常规插入产生的redo size | apppend插入产生的redo size | apppend + parallel插入产生的redo size |
|---|---|---|---|---|
| 数据库模式 | archive | |||
| nologing | t2 | 67752144 | 143436 | 21916 |
| loging | t3 | 67875992 | 68384900 | 21308 |
| 数据库模式 | noarchive | |||
| nologing | t2 | 67754744 | 143480 | 21896 |
| loging | t3 | 67757328 | 143420 | 21896 |
1）数据库处于ARCHIVE模式时，
对logging表执行append插入，是对性能没有优化的。加并行parallel才会有影响。
2）数据库处于NOARCHIVE模式时，对logging表执行append插入，可以有效的提升性能。当然加并行parallel效果会更好