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https://issues.apache.org/jira/browse/HBASE-10244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13863526#comment-13863526
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Enis Soztutar commented on HBASE-10244:
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Yes, we are storing mvcc numbers in hfiles, but since the mvcc numbers
lifecycle , and a region scanner's lifecycle is bound by the RS lifetime we are
just using the lowest mvcc read number of all the open scanners to manage the
low watermark. I agree that we can implement a timeout based low watermark
tracking. The client-side open scanners will receive the mvcc number. They
would have to connect to the next region in an absolute time-bound (like 30
min), otherwise they will fail the scan completely. The RS then can manage a
time window for mvcc numbers to expire the mvcc read numbers since any scanner
not connecting for the last 30 min will be rejected.
> store mvcc in store files per KV for longer time, discard during compactions
> based on scanner timeout
> -----------------------------------------------------------------------------------------------------
>
> Key: HBASE-10244
> URL: https://issues.apache.org/jira/browse/HBASE-10244
> Project: HBase
> Issue Type: Sub-task
> Components: Compaction, regionserver
> Reporter: Sergey Shelukhin
> Priority: Minor
>
> -Initially, we can store via KV tag. For perf reasons, it might make sense to
> make it a first-class member of KV, but that would require HFileV4-
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