常見dml、ddl語句使用nologging選項所生成的redo和undo大小比較

說明：反映undo、redo佔用量的統計指標是：

undo change vector size

redo size

 

DDL/DML Operations	Direct-path	nologging		parallel	noarchivelog mode		archivelog mode
					Redo	Undo	Redo	Undo
Insert into XXX select * from YYY	N	N		N	19076324	627240	18938620	612980
Alter table XXX nologging; Insert into XXX select * from YYY;	N	Y		N	19085860	631584	18935548	612912
Insert /*+ append */ into XXX select * from YYY	Y	N		N	26628	4048(only metadata)	19145656	4048
Alter table XXX nologging; Insert /*+ append */ into XXX select * from YYY	Y	Y		N	26868	4048(only metadata)	26836	4048
Create table XXX as select * from YYY	Y	N		N	77624	18500	19162220	15468
Create table XXX nologging as select * from YYY	Y	Y		N	52160	11176	52408	11248
Alter table XXX move nologging;	N	Y		N	36288	6208	36576	6208
Alter table XXX move;	N	N		N	39788	7288	19154024	5972
Create index XXX	N	N		N	21280	1864	3093616	1888
Create index XXX nologging	N	Y		N	22264	2208	22620	2232
update XXX set	N	N		N	122903212	47987880	122403692	47786680
Update /*+ parallel(5) */ XXX set	N	N	Y(Queries)		121629928	46706296	120818336	46466056
Alter table XXX nologging; update XXX set	N	Y	N		123155288	48006404	110396512	41617700
Alter table XXX nologging; update /*+ parallel(5) */ XXX set	N	Y	Y(Queries)		119748064	46152324	120205036	46261536
Alter session enable parallel dml Update /*+ parallel(5) */ XXX set	N	N	Y(DML)		59846488	24680220	59740516	24611672
Alter table XXX nologging; Alter session enable parallel dml Update /*+ parallel(5) */ XXX set	N	Y	Y(DML)		59831756	24673396	59717116	24602628
delete XXX;	N	N	N		60684720	37650208	61770472	38254648
delete /*+parallel(5) */ XXX;	N	N	Y(Queries)		60685416	37650436	61988568	38461832
Alter table XXX nologging; delete XXX;	N	Y	N		60684956	37650216	61989984	38460424
Alter table XXX nologging; delete /*+parallel(5) */ XXX;	N	Y	Y(Queries)		60685092	37650224	61986156	38459172
Alter session enable parallel dml delete /*+parallel(5) */ aabbn;	N	N	Y(DML)		65072896	40990412	61979216	38457372
Alter table XXX nologging; Alter session enable parallel dml delete /*+parallel(5) */ aabbn;	N	Y	Y(DML)		65073828	40998048	62022668	38500548

 

結論：

一、insert into：非direct方式下noarchivelog和archivelog兩種模式均產生大量undo、redo；direct方式下noarchivelog模式均產生少許undo、redo；direct+logging方式下archivelog模式產生少許undo、大量redo；direct+nologging方式下archivelog模式產生少許undo、少許redo

 

二、create table as：CTAS自己就是一種direct的操做，CTAS+logging方式下noarchivelog模式產生少許redo、少許undo；CTAS+nologging方式下noarchivelog模式產生更少許redo、更少許undo；CTAS+logging方式下archivelog模式產生少許undo、大量redo；CTAS+nologging方式下archivelog模式產生少許undo、少許redo；

 

三、alter table ... move：nologging方式下noarchivelog模式產生少許undo、少許redo；nologging方式下archivelog模式產生少許undo、少許redo；logging方式下archivelog模式產生少許undo、大量redo

 

四、create index：logging+nologging方式下noarchivelog模式產生少許undo、少許redo；logging方式下archivelog模式產生少許undo、大量redo；nologging方式下archivelog模式產生少許undo、少許redo

 

五、update：enable parallel方式下，noarchivelog+ archivelog模式生成少許undo、少許redo；非enable parallel方式下，noarchivelog+ archivelog模式生成大量undo、大量redo

 

六、delete：任何組合都會生成大量undo、大量redo