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https://issues.apache.org/jira/browse/HBASE-8763?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jeffrey Zhong updated HBASE-8763:
---------------------------------
Resolution: Fixed
Fix Version/s: 0.99.0
Hadoop Flags: Reviewed
Status: Resolved (was: Patch Available)
Thanks [[email protected]] for all the discussions & reviews! I've fixed all
the javadoc warnings & removed all references of MutableLong. I'll create
follow up JIRA shortly.
{quote}
Is there ever a time when we know the mvcc constructing a Cell such that we can
shove it in on Construction other than at deserializing or clone time?
{quote}
Since we do late-binding style sequence Id assignment, it's hard to "shove it
in on Construction" because we firstly add KVs into memstore and then append to
WAL.
> 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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