Oracle NoLogging Append 方式减少批量insert的redo_size

时间：2017-09-06 14:32:13 阅读：279 评论：0 收藏：0 [点我收藏+]

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业务处理中，很多时候使用实表临时表处理中间结果，而实表的Insert操作缺省会记录redo log，针对此问题收集相关测试总结信息如下：

【转】常见dml、ddl语句使用nologging选项所生成的redo和undo大小比较

DDL/DML Operations	Direct-path	nologging	parallel	Noarchivelog Redo	Noarchivelog Undo	Archivelog Redo	Archivelog 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

结论：

1、insert into：非direct方式下noarchivelog和archivelog两种模式均产生大量undo、redo；direct方式下noarchivelog模式均产生少量undo、redo；direct+logging方式下archivelog模式产生少量undo、大量redo；direct+nologging方式下archivelog模式产生少量undo、少量redo

2、create table as：CTAS本身就是一种direct的操作，CTAS+logging方式下noarchivelog模式产生少量redo、少量undo；CTAS+nologging方式下noarchivelog模式产生更少量redo、更少量undo；CTAS+logging方式下archivelog模式产生少量undo、大量redo；CTAS+nologging方式下archivelog模式产生少量undo、少量redo；