【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较

1  BLOG文档结构图

【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

2  前言部分

2.1  导读和注意事项

各位技术爱好者,看完本文后,你可以掌握如下的技能,也可以学到一些其它你所不知道的知识,~O(∩_∩)O~:

① 系统和会话级别的REDO和UNDO量的查询

② NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较(重点)

  Tips:

① 本文在itpub()、博客园()和微信公众号(xiaomaimiaolhr)有同步更新。

② 文章中用到的所有代码,相关软件,相关资料请前往小麦苗的云盘下载()。

③ 若网页文章代码格式有错乱,推荐使用360浏览器,也可以下载pdf格式的文档来查看,pdf文档下载地址:,另外itpub格式显示有问题,也可以去博客园地址阅读。

④ 本篇BLOG中命令的输出部分需要特别关注的地方我都用,thread 2的最大归档日志号为43是需要特别关注的地方;而命令一般使用黄色背景和红色字体标注;对代码或代码输出部分的注释一般采用蓝色字体表示。

List of Archived Logs in backup set 11

Thrd Seq     Low SCN    Low Time            Next SCN   Next Time

---- ------- ---------- ------------------- ---------- ---------

1    32      1621589    2015-05-29 11:09:52 1625242    2015-05-29 11:15:48

1    33      1625242    2015-05-29 11:15:48 1625293    2015-05-29 11:15:58

2    42      1613951    2015-05-29 10:41:18 1625245    2015-05-29 11:15:49

2    43      1625245    2015-05-29 11:15:49 1625253    2015-05-29 11:15:53

[ZHLHRDB1:root]:/>lsvg -o

T_XLHRD_APP1_vg

rootvg

[ZHLHRDB1:root]:/>

00:27:22 SQL> alter tablespace idxtbs read write;

====》2097152*512/1024/1024/1024=1G

 

本文如有错误或不完善的地方请大家多多指正,ITPUB留言或QQ皆可,您的批评指正是我写作的最大动力。

3  REDOUNDO生成量的查询

说明:反映UNDO、REDO占用量的统计指标是:

UNDO:undo change vector size

REDO:redo size

1、查看全局数据库REDO生成量,可以通过V$SYSSTAT视图查询

SELECT NAME,

VALUE

FROM   V$SYSSTAT

WHERE  NAME = 'redo size';

【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

2、查看当前会话的REDO生成量,可以通过V$MYSTAT或V$SESSTAT视图查询

create or replace view redo_size as

SELECT VALUE

FROM   v$mystat   my,

v$statname  st

WHERE  my.statistic# =st.STATISTIC#

AND    st.name = 'redo size';

----下边的实验将用到这个视图

CREATE OR REPLACE VIEW VW_REDO_UNDO_LHR AS

SELECT (SELECT NB.VALUE

FROM V$MYSTAT NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'redo size') REDO,

(SELECT NB.VALUE

FROM V$MYSTAT NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'undo change vector size') UNDO

FROM DUAL;

 

或:

CREATE OR REPLACE VIEW VW_REDO_UNDO_LHR AS

SELECT (SELECT NB.VALUE

FROM v$sesstat NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'redo size'

AND NB.SID=USERENV('SID')) REDO,

(SELECT NB.VALUE

FROM v$sesstat NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'undo change vector size'

AND NB.SID=USERENV('SID')) UNDO

FROM DUAL;

 

 

4  实验过程

4.1  实验环境准备

--记录REDO和UNDO量的视图

CREATE OR REPLACE VIEW VW_REDO_UNDO_LHR AS

SELECT (SELECT NB.VALUE

FROM V$MYSTAT NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'redo size') REDO,

(SELECT NB.VALUE

FROM V$MYSTAT NB, V$STATNAME ST

WHERE NB.STATISTIC# = ST.STATISTIC#

AND ST.NAME = 'undo change vector size') UNDO

FROM DUAL;

--准备中间表,T_A为500W,T_B为500W的数据量,T_A表删掉少量数据

DROP TABLE   T_A PURGE;

DROP TABLE   T_B PURGE;

CREATE TABLE T_A AS SELECT * FROM DBA_OBJECTS;

CREATE TABLE T_B AS SELECT * FROM DBA_OBJECTS;

INSERT INTO T_A SELECT * FROM T_A;

INSERT INTO T_A SELECT * FROM T_A;

INSERT INTO T_A SELECT * FROM T_A;

INSERT INTO T_A SELECT * FROM T_A;

INSERT INTO T_A SELECT * FROM T_A;

INSERT INTO T_A SELECT * FROM T_A;

COMMIT;

INSERT INTO T_B SELECT * FROM T_A;

DELETE FROM T_A WHERE OBJECT_ID>=90000;

COMMIT;

SELECT COUNT(1) FROM T_A;      --5548800

SELECT COUNT(1) FROM T_B;      --5668976

--记录测试结果

DROP TABLE T_RU_160929_LHR;

CREATE TABLE T_RU_160929_LHR (

ID NUMBER PRIMARY KEY,

SQL_TYPES VARCHAR2(255),

SQL1 VARCHAR2(255),

SQL2 VARCHAR2(255),

SQL3 VARCHAR2(4000),

IS_DIRECT VARCHAR2(20),

IS_NOLOGGING VARCHAR2(20),

IS_PARALLEL VARCHAR2(20),

ARCH_REDO NUMBER,

ARCH_UNDO NUMBER,

NOARCH_REDO NUMBER,

NOARCH_UNDO NUMBER,

ARCH_USE_TIME NUMBER,

NOARCH_USE_TIME NUMBER,

SQL_EXPLAIN CLOB,

COMMENTS VARCHAR2(255)

);

--插入要执行的SQL语句

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (1, 'CTAS', NULL, NULL, 'CREATE TABLE T_RU_CTAS_LHR AS SELECT * FROM T_B', 'Y', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (2, 'CTAS', NULL, NULL, 'CREATE TABLE T_RU_CTAS_LHR NOLOGGING AS SELECT * FROM T_B', 'Y', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (3, 'CTAS', NULL, NULL, 'CREATE TABLE T_RU_CTAS_LHR NOLOGGING PARALLEL 4 AS SELECT * FROM T_B', 'Y', 'Y', 'Y');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (4, 'CI', NULL, NULL, 'CREATE INDEX IND_TA_LHR ON T_A(OBJECT_ID)', 'N', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (5, 'CI', NULL, NULL, 'CREATE INDEX IND_TA_LHR ON T_A(OBJECT_ID) NOLOGGING', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (6, 'CI', NULL, NULL, 'CREATE INDEX IND_TA_LHR ON T_A(OBJECT_ID) NOLOGGING PARALLEL 4', 'N', 'Y', 'Y');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (7, 'MOVE', NULL, NULL, 'ALTER TABLE T_A MOVE', 'N', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (8, 'MOVE', NULL, NULL, 'ALTER TABLE T_A MOVE NOLOGGING', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (9, 'MOVE', NULL, NULL, 'ALTER TABLE T_A MOVE NOLOGGING PARALLEL 4', 'N', 'Y', 'Y');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (10, 'INSERT', NULL, NULL, 'INSERT INTO T_A SELECT * FROM T_B', 'N', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (11, 'INSERT', 'ALTER TABLE T_A NOLOGGING', NULL, 'INSERT INTO T_A SELECT * FROM T_B', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (12, 'INSERT', NULL, NULL, 'INSERT /*+ APPEND */ INTO T_A SELECT * FROM T_B', 'Y', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (13, 'INSERT', 'ALTER TABLE T_A NOLOGGING', NULL, 'INSERT /*+ APPEND */ INTO T_A SELECT * FROM T_B', 'Y', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (14, 'INSERT', 'ALTER TABLE T_A NOLOGGING', NULL, 'INSERT /*+ PARALLEL(4) APPEND */ INTO T_A SELECT * FROM T_B', 'Y', 'Y', 'Y');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (15, 'INSERT', 'ALTER TABLE T_A NOLOGGING', 'ALTER SESSION ENABLE PARALLEL DML', 'INSERT /*+ PARALLEL(4) APPEND */ INTO T_A SELECT * FROM T_B', 'Y', 'Y', 'Y(PDML)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (16, 'UPDATE', NULL, NULL, 'UPDATE  T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (17, 'UPDATE', NULL, NULL, 'UPDATE /*+ PARALLEL(4) */ T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'N', 'Y(Queries)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (18, 'UPDATE', 'ALTER TABLE T_A NOLOGGING', NULL, 'UPDATE  T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (19, 'UPDATE', 'ALTER TABLE T_A NOLOGGING', NULL, 'UPDATE  /*+ PARALLEL(4) */ T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'Y', 'Y(Queries)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (20, 'UPDATE', 'ALTER SESSION ENABLE PARALLEL DML', NULL, 'UPDATE /*+ PARALLEL(4) */ T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'N', 'Y(PDML)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (21, 'UPDATE', 'ALTER TABLE T_A NOLOGGING', 'ALTER SESSION ENABLE PARALLEL DML', 'UPDATE /*+ PARALLEL(4) */ T_A T SET T.DATA_OBJECT_ID =(SELECT TB.DATA_OBJECT_ID FROM T_B TB WHERE TB.OBJECT_ID = T.OBJECT_ID AND ROWNUM=1) WHERE T.OBJECT_ID <= 1000', 'N', 'Y', 'Y(PDML)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (22, 'MERGE', 'ALTER TABLE T_A NOLOGGING', NULL, 'MERGE  INTO T_A T USING (SELECT TA.ROWID ROWIDS, MAX(TB.DATA_OBJECT_ID) DATA_OBJECT_ID FROM T_B TB, T_A TA WHERE TB.OBJECT_ID = TA.OBJECT_ID AND TA.OBJECT_ID <= 1000  GROUP BY TA.ROWID) T1 ON (T.ROWID = T1.ROWIDS)WHEN MATCHED THEN UPDATE SET T.DATA_OBJECT_ID = T1.DATA_OBJECT_ID', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (23, 'MERGE', 'ALTER TABLE T_A NOLOGGING', NULL, 'MERGE /*+ PARALLEL(4) */ INTO T_A T USING (SELECT TA.ROWID ROWIDS, MAX(TB.DATA_OBJECT_ID) DATA_OBJECT_ID FROM T_B TB, T_A TA WHERE TB.OBJECT_ID = TA.OBJECT_ID AND TA.OBJECT_ID <= 1000  GROUP BY TA.ROWID) T1 ON (T.ROWID = T1.ROWIDS)WHEN MATCHED THEN UPDATE SET T.DATA_OBJECT_ID = T1.DATA_OBJECT_ID', 'N', 'Y', 'Y(Queries)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (24, 'MERGE', 'ALTER TABLE T_A NOLOGGING', 'ALTER SESSION ENABLE PARALLEL DML', 'MERGE /*+ PARALLEL(4) */ INTO T_A T USING (SELECT TA.ROWID ROWIDS, MAX(TB.DATA_OBJECT_ID) DATA_OBJECT_ID FROM T_B TB, T_A TA WHERE TB.OBJECT_ID = TA.OBJECT_ID AND TA.OBJECT_ID <= 1000  GROUP BY TA.ROWID) T1 ON (T.ROWID = T1.ROWIDS)WHEN MATCHED THEN UPDATE SET T.DATA_OBJECT_ID = T1.DATA_OBJECT_ID', 'N', 'Y', 'Y(PDML)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (25, 'DELETE', NULL, NULL, 'DELETE FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'N', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (26, 'DELETE', NULL, NULL, 'DELETE /*+ PARALLEL(4) */ FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'N', 'Y(Queries)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (27, 'DELETE', 'ALTER TABLE T_A NOLOGGING', NULL, 'DELETE FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'Y', 'N');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (28, 'DELETE', 'ALTER TABLE T_A NOLOGGING', NULL, 'DELETE /*+ PARALLEL(4) */ FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'Y', 'Y(Queries)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (29, 'DELETE', 'ALTER SESSION ENABLE PARALLEL DML', NULL, 'DELETE /*+ PARALLEL(4) */ FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'N', 'Y(PDML)');

INSERT INTO T_RU_160929_LHR (ID, SQL_TYPES, SQL1, SQL2, SQL3, IS_DIRECT, IS_NOLOGGING, IS_PARALLEL) VALUES (30, 'DELETE', 'ALTER TABLE T_A NOLOGGING', 'ALTER SESSION ENABLE PARALLEL DML', 'DELETE /*+ PARALLEL(4) */ FROM  T_A T  WHERE T.OBJECT_ID IN  ( SELECT TB.OBJECT_ID FROM T_B TB) AND T.OBJECT_ID <= 1000', 'N', 'Y', 'Y(PDML)');

COMMIT;

插入完成后查询结果:

SELECT ID,

SQL_TYPES,

SQL1,

SQL2,

SQL3,

IS_DIRECT,

IS_NOLOGGING,

IS_PARALLEL

FROM T_RU_160929_LHR D

ORDER BY D.ID;

【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

下边的存过可以测试REDO和UNDO的量,至于该存过的算法大家自己看吧。

--创建存储过程,用来测试REDO量

CREATE OR REPLACE PROCEDURE PRO_TEST_RU_LHR AS

V_REDO       NUMBER := 0;

V_UNDO       NUMBER := 0;

V_REDO1      NUMBER := 0;

V_UNDO1      NUMBER := 0;

V_ARCH       VARCHAR2(30);

V_START_TIME NUMBER := 0;

V_END_TIME   NUMBER := 0;

BEGIN

SELECT D.LOG_MODE INTO V_ARCH FROM V$DATABASE D;

FOR CUR IN (SELECT D.ID, D.SQL1, D.SQL2, D.SQL3

FROM T_RU_160929_LHR D

ORDER BY D.ID) LOOP

BEGIN

EXECUTE IMMEDIATE CUR.SQL1;

EXCEPTION

WHEN OTHERS THEN

NULL;

END;

BEGIN

EXECUTE IMMEDIATE CUR.SQL2;

EXCEPTION

WHEN OTHERS THEN

NULL;

END;

SELECT DBMS_UTILITY.GET_TIME INTO V_START_TIME FROM DUAL;

SELECT V.REDO, V.UNDO INTO V_REDO, V_UNDO FROM VW_REDO_UNDO_LHR V;

EXECUTE IMMEDIATE CUR.SQL3;

SELECT V.REDO, V.UNDO INTO V_REDO1, V_UNDO1 FROM VW_REDO_UNDO_LHR V;

SELECT DBMS_UTILITY.GET_TIME INTO V_END_TIME FROM DUAL;

ROLLBACK;

IF V_ARCH = 'ARCHIVELOG' THEN

UPDATE T_RU_160929_LHR T

SET T.ARCH_REDO     = V_REDO1 - V_REDO,

T.ARCH_UNDO     = V_UNDO1 - V_UNDO,

T.ARCH_USE_TIME =

(V_END_TIME - V_START_TIME) / 100,

T.COMMENTS      = T.COMMENTS || 'ARCHIVELOG:' ||

(SELECT COUNT(1) FROM T_A) || '  '

WHERE T.ID = CUR.ID;

ELSE

UPDATE T_RU_160929_LHR T

SET T.NOARCH_REDO     = V_REDO1 - V_REDO,

T.NOARCH_UNDO     = V_UNDO1 - V_UNDO,

T.NOARCH_USE_TIME =

(V_END_TIME - V_START_TIME) / 100,

T.COMMENTS        = T.COMMENTS || 'NOARCHIVELOG:' ||

(SELECT COUNT(1) FROM T_A) || '  '

WHERE T.ID = CUR.ID;

END IF;

COMMIT;

EXECUTE IMMEDIATE 'ALTER TABLE T_A LOGGING';

EXECUTE IMMEDIATE 'ALTER SESSION DISABLE PARALLEL DML';

EXECUTE IMMEDIATE 'ALTER SYSTEM FLUSH BUFFER_CACHE';

BEGIN

EXECUTE IMMEDIATE 'DROP INDEX IND_TA_LHR';

EXCEPTION

WHEN OTHERS THEN

NULL;

END;

BEGIN

EXECUTE IMMEDIATE 'DROP TABLE T_RU_CTAS_LHR PURGE';

EXCEPTION

WHEN OTHERS THEN

NULL;

END;

END LOOP;

END;

4.2  开始实验

4.2.1  归档模式

增加日志组的个数,避免因为日志切换导致的等待。

SYS@lhrdb> select * from v$version;

BANNER

--------------------------------------------------------------------------------

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

PL/SQL Release 11.2.0.4.0 - Production

CORE    11.2.0.4.0      Production

TNS for IBM/AIX RISC System/6000: Version 11.2.0.4.0 - Production

NLSRTL Version 11.2.0.4.0 - Production

SYS@lhrdb> select GROUP#,BYTES,STATUS from v$log;

GROUP#      BYTES STATUS

---------- ---------- ----------------

1  104857600 ACTIVE

2  104857600 ACTIVE

3  104857600 ACTIVE

4  104857600 CURRENT

5  104857600 ACTIVE

6  104857600 ACTIVE

6 rows selected.

SYS@lhrdb> archive log list;

Database log mode              Archive Mode

Automatic archival             Enabled

Archive destination            USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence     401

Next log sequence to archive   406

Current log sequence           406

SYS@lhrdb> SET TIMING ON

SYS@lhrdb> exec PRO_TEST_RU_LHR;

PL/SQL procedure successfully completed.

Elapsed: 00:12:49.83

SYS@lhrdb>

在PL/SQL DEVELOPER中查询结果:

SELECT D.*

FROM T_RU_160929_LHR D

ORDER BY D.ID;

4.2.2  非归档模式

SYS@lhrdb> shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

SYS@lhrdb> startup mount

ORACLE instance started.

Total System Global Area 1720328192 bytes

Fixed Size                  2247072 bytes

Variable Size             486540896 bytes

Database Buffers         1224736768 bytes

Redo Buffers                6803456 bytes

Database mounted.

SYS@lhrdb> alter database noarchivelog;

Database altered.

SYS@lhrdb> alter database open;

Database altered.

SYS@lhrdb> archive log list;

Database log mode              No Archive Mode

Automatic archival             Disabled

Archive destination            USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence     419

Current log sequence           424

SYS@lhrdb>

SYS@lhrdb> set timing on

SYS@lhrdb> exec PRO_TEST_RU_LHR;

PL/SQL procedure successfully completed.

Elapsed: 00:13:31.67

在PL/SQL DEVELOPER中查询结果:

SELECT D.*

FROM T_RU_160929_LHR D

ORDER BY D.ID;

以上测试过程,可以多做几次,然后取其平均值,多次测试前将结果表清空:

UPDATE T_RU_160929_LHR T

SET T.ARCH_REDO       = '',

T.ARCH_UNDO       = '',

T.ARCH_USE_TIME   = '',

T.NOARCH_REDO     = '',

T.NOARCH_UNDO     = '',

T.NOARCH_USE_TIME = '',

T.COMMENTS        = '';

COMMIT;

 

4.3  实验结果

【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

根据以上的实验可以得到一些结论:关于表日志模式(LOGGING/NOLOGGING)、插入模式(APPEND/NOAPPEND)、运行模式(归档/非归档)和并行模式下,REDO、UNDO和执行速度的情况大约如下表所示:

【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

5  结论

(一)关于效率的结论:

1、INSERT INTO: 在APPEND提示的情况下,NOLOGGING或NOARCHIVELOG满足一个即产生少量的REDO和UNDO;另外PARALLEL默认是以DIRECT的方式进行加载数据的,一般在并行情况下SQL执行速度提高。

2、CTAS:CTAS本身就是一种DIRECT的操作,归档模式+NOLOGGING模式产生少量REDO;并行模式下时间大幅度减少,但生成的REDO和UNDO成倍增长。

3、ALTER TABLE ... MOVE:ARCHIVELOG+NOLOGGING模式产生少量REDO;并行模式下时间大幅度减少,但生成的REDO和UNDO成倍增长。

4、CREATE INDEX:ARCHIVELOG+NOLOGGING模式产生少量REDO;并行模式下时间大幅度减少,但生成的REDO和UNDO成倍增长。

5、UPDATE:任何组合都会生成大量UNDO、大量REDO;有关并行的性能需要查询执行计划再做定夺。

6、DELETE:任何组合都会生成大量UNDO、大量REDO;加上并行可以大幅度提高SQL的执行速度。

7、MERGE:在关联更新的情况下,MERGE语句的非关联形式的性能比UPDATE要高,若加上并行性能更好。

8、总体而言,非归档比归档模式下性能高

(二)关于属性NOLOGGING和并行度的结论:

1、对于形如: ;的SQL语句而言,创建的表或索引的并行度是4,日志模式是NOLOGGING,所以,生产库上对于重要的表和索引需要修改为LOGGING,并行度可以根据需要来修改,ALTER TABLE TT LOGGING NOPARALLEL;或ALTER INDEX IDNX11 LOGGING NOPARALLEL;

2、对于形如:;;的SQL语句而言,修改后的表的并行度依然为原来的并行度,但是索引的并行度是4,而日志模式都是NOLOGGING,所以,生产库上对于重要的表和索引需要修改为LOGGING,并行度可以根据需要来修改,ALTER TABLE TT LOGGING NOPARALLEL;或ALTER INDEX IDNX11 LOGGING NOPARALLEL;

总之一句话,若执行了上边形式的SQL语句后,最好都修改一下表或索引的并行度及其日志模式。

 

(三)APPEND使用注意事项:

1、建议不要经常使用APPEND,这样表空间会一直在高水位上,除非你这个表只插不删。

2、以APPEND方式插入记录后,要执行COMMIT,才能对表进行查询。否则会出现错误:ORA-12838: 无法在并行模式下修改之后读/修改对象。

3、APPEND对INSERT INTO ... VALUES语句不起作用,需要使用11gR2的APPEND_VALUES来提示才可以直接路径加载,注意:APPEND_VALUES对INSERT INTO ... SELECT也起作用。

4、APPEND使用HWM之上的块,减少了搜索FREELIST上块的时间。

5、在归档模式下:NOLOGGING+APPEND才会显著减少REDO数量;在非归档模式下:单独APPEND即可减少REDO数量。

6、APPEND不会减少相关表的索引上产生的REDO数量。

7、APPEND的插入操作是给表加上6级排它锁,会阻塞表上的所有DML语句。

8、每提交一次,就会取一个新的BLOCK存放,高水位就上推一个BLOCK,若在LOOP循环中,外部循环100W次,但是每循环一次只有一行符合条件的数据插入,这样,大量单条/*+APPEND*/插入,就会使得表急剧增大,除对INSERT本身造成性能影响之外,对以后的SELECT、UPDATE、DELETE更是带来更巨大的性能影响。

(四)NOLOGGING使用注意事项:

1、NOLOGGING插完后最好对表做个备份。生产上重要的表不建议设置NOLOGGING属性。

2、如果库处在FORCE LOGGING模式下,此时的NOLOGGING方式是无效的。

(五)PDML使用注意事项:

1、必须使用ALTER SESSION ENABLE PARALLEL DML;才可以启动PDML。

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【知识点整理】Oracle中NOLOGGING、APPEND、ARCHIVE和PARALLEL下,REDO、UNDO和执行速度的比较-LMLPHP

05-02 06:23