[jira] [Commented] (HBASE-8763) Combine MVCC and SeqId

["Hudson (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-8763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15135681#comment-15135681 ] 

Hudson commented on HBASE-8763:
-------------------------------

SUCCESS: Integrated in HBase-1.1-JDK8 #1741 (See [https://builds.apache.org/job/HBase-1.1-JDK8/1741/])
HBASE-15213 Fix increment performance regression caused by HBASE-8763 on (stack: rev 7ac940b4b06c3ac14cb6d2702e2a5db415d8a6f8)
* hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MultiVersionConsistencyControl.java


> Combine MVCC and SeqId
> ----------------------
>
>                 Key: HBASE-8763
>                 URL: https://issues.apache.org/jira/browse/HBASE-8763
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>            Reporter: Enis Soztutar
>            Assignee: Jeffrey Zhong
>            Priority: Critical
>             Fix For: 0.99.0
>
>         Attachments: HBase MVCC & LogSeqId Combined.pdf, hbase-8736-poc.patch, hbase-8763-poc-v1.patch, hbase-8763-v1.patch, hbase-8763-v2.patch, hbase-8763-v3.patch, hbase-8763-v4.patch, hbase-8763-v5.1.patch, hbase-8763-v5.2.patch, hbase-8763-v5.patch, hbase-8763_wip1.patch
>
>
> HBASE-8701 and a lot of recent issues include good discussions about mvcc + seqId semantics. It seems that having mvcc and the seqId complicates the comparator semantics a lot in regards to flush + WAL replay + compactions + delete markers and out of order puts. 
> Thinking more about it I don't think we need a MVCC write number which is different than the seqId. We can keep the MVCC semantics, read point and smallest read points intact, but combine mvcc write number and seqId. This will allow cleaner semantics + implementation + smaller data files. 
> We can do some brainstorming for 0.98. We still have to verify that this would be semantically correct, it should be so by my current understanding.



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