I have got it , Thanks a lot... 2015-11-20 10:26 GMT+08:00 hongbin ma <[email protected]>:
> the timestamp of any resource is mainly to avoid write conflict. > say user A reads a resource R and made some modifications to make it R'. > When A tries to persistent R' , it has to make sure resource R has not > been changed by another concurrent user B. > > This patch fixes potential bug when updating cube segments(especially in > 2.x branches where streaming data ingestion is enabled, more frequent cube > updating is occurring) > > the scenario is described by liyang: > > - A read content > - B write content & timestamp > - A read timestamp* (notice A did not read timestamp and content at same > time, this is the root cause)* > - A write again which overwrite B without detection > > if you're using versions prior to 2.0, it's fixing a bug that almost never > happened(in theory it can happen,but we have never seen it) > > > > -- > Regards, > > *Bin Mahone | 马洪宾* > Apache Kylin: http://kylin.io > Github: https://github.com/binmahone >
