COMBINE主题的文章列表，还有COMBINE的技术要点_第1页

hadoop中Combiner的作用是什么?

　　在Hadoop中，Combiner的作用是在MapReduce过程中对Mapper阶段输出的数据进行局部合并，以减少数据传输量，提高效率。Combiner通常用于一些可以局部聚合的操作，例如对Mapper输出的键值对进行计数、求和、平均值等。通过使用Combiner，可以将部分数据的处理工作从Reducer之前转移...

开发笔记 ·2024-08-14

hadoop中combiner是什么

Combiner（合并器）在Hadoop中，Combiner（合并器）是一个可选的阶段，用于优化MapReduce任务的性能。它是在Map阶段输出之后、规约（reduction）之前执行的。Combiner的作用是在Map任务的本地节点上对Map阶段的输出进行局部聚合。它接收Map任务输出的键值对，并将具有相同键的键值...

开发笔记 ·2024-01-23

ORA-26809: Capture aborted: checkpoint-free mode requires combined capture and apply mode.

文档解释ORA-26809:Captureaborted:checkpoint-freemoderequirescombinedcaptureandapplymode.Cause:Therequirementsforcombinedcaptureandapplymodewerebroken.Action:Restore...

IT技术学习 ·2023-07-26

ORA-26806: Remote database could not support combined capture and apply optimization.

文档解释ORA-26806:Remotedatabasecouldnotsupportcombinedcaptureandapplyoptimization.Cause:TheremotedatabasehasaversionlowerthanOracle11.0andhencedoesnotunderstandcom...

IT技术学习 ·2023-07-26

ORA-14165: MODIFY DEFAULT ATTRIBUTES FOR PARTITION may not be combined with other operations

文档解释ORA-14165:MODIFYDEFAULTATTRIBUTESFORPARTITIONmaynotbecombinedwithotheroperationsCause:ALTERTABLEorALTERINDEXstatementattemptedtocombineMODIFYDEFAULTATTRIBUT...

IT技术学习 ·2023-07-25

ORA-26828: XStream outbound server “string” requires combined capture and apply mode.

文档解释ORA-26828:XStreamoutboundserver“string”requirescombinedcaptureandapplymode.Cause:ThespecifiedXStreamoutboundserverwasnotincombinedcaptureandappl...

IT技术学习 ·2023-07-22

ORA-14613: Attempt to generate name from parent name string and template name string failed as the combine named would have been longer than allowed

文档解释ORA-14613:AttempttogeneratenamefromparentnamestringandtemplatenamestringfailedasthecombinenamedwouldhavebeenlongerthanallowedCause:Anynamegeneratedfromapart...

IT技术学习 ·2023-07-19

ORA-26902: string propagation sender in the combined capture and apply mode is to be suspended while apply is enabled.

文档解释ORA-26902:stringpropagationsenderinthecombinedcaptureandapplymodeistobesuspendedwhileapplyisenabled.Cause:Thecorrespondingsubscriberwasdroppedorsplit.Action...

IT技术学习 ·2023-07-18

ORA-26810: Apply “string” on database “string” is in the mode of combined capture and apply.

文档解释ORA-26810:Apply“string”ondatabase“string”isinthemodeofcombinedcaptureandapply.Cause:Thecombinedcaptureandapplyoptimizationcouldnotbe...

IT技术学习 ·2023-07-16

ORA-14141: ALTER INDEX VISIBLE|INVISIBLE may not be combined with other operations

文档解释ORA-14141:ALTERINDEXVISIBLE|INVISIBLEmaynotbecombinedwithotheroperationsCause:ALTERINDEXstatementattemptedtocombineaVISIBLE|INVISIBLEoperationwithsomeothero...

IT技术学习 ·2023-07-11

ORA-14133: ALTER TABLE MOVE cannot be combined with other operations

文档解释ORA-14133:ALTERTABLEMOVEcannotbecombinedwithotheroperationsCause:AnattemptwasmadetocombineanALTERTABLEMOVEstatementwithanotheroperation,suchasMODIFY.Action:...

IT技术学习 ·2023-07-11

ORA-14047: ALTER TABLE|INDEX RENAME may not be combined with other operations

文档解释ORA-14047:ALTERTABLE|INDEXRENAMEmaynotbecombinedwithotheroperationsCause:ALTERTABLEorALTERINDEXstatementattemptedtocombineaRENAMEoperationwithsomeotheropera...

IT技术学习 ·2023-07-11

ORA-12497: maximum combined categories exceeds string

文档解释ORA-12497:maximumcombinedcategoriesexceedsstringCause:ThemaximumnumberofdescriptivecategoriesplusreleasecategoriessupportedbytheMLSpolicywasexceeded.Action:...

IT技术学习 ·2023-07-11

ORA-14175: a subpartition maintenance operation may not be combined with other operations

文档解释ORA-14175:asubpartitionmaintenanceoperationmaynotbecombinedwithotheroperationsCause:ALTERTABLEorALTERINDEXstatementattemptedtocombineasubpartitionmaintenanc...

IT技术学习 ·2023-07-11

ORA-12987: cannot combine drop column with other operations

文档解释ORA-12987:cannotcombinedropcolumnwithotheroperationsCause:AnattemptwasmadetocombinedropcolumnwithotherALTERTABLEoperations.Action:Ensurethatdropcolumnisthes...

IT技术学习 ·2023-07-10