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https://issues.apache.org/jira/browse/HBASE-4241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13121594#comment-13121594
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Lars Hofhansl commented on HBASE-4241:
--------------------------------------

During memstore flush we only want to read from the snapshot. There is no 
principal reason why using memstore scanner for this wouldn't work (need to 
make sure that kvsetIt never has anything to iterate).

The memstore scanner now also mucks with readpoints (although I think that is 
new). It seemed easier to just wrap a simple scanner wrapper instance around 
the snapshot.

Wanna try using memstore scanner? If it turns out to be simpler I am happy to 
change it.
                
> Optimize flushing of the Store cache for max versions and (new) min versions
> ----------------------------------------------------------------------------
>
>                 Key: HBASE-4241
>                 URL: https://issues.apache.org/jira/browse/HBASE-4241
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>    Affects Versions: 0.92.0
>            Reporter: Lars Hofhansl
>            Assignee: Lars Hofhansl
>             Fix For: 0.92.0
>
>         Attachments: 4241-v2.txt, 4241-v8.txt, 4241.txt
>
>
> As discussed with with Jon, there is room for improvement in how the memstore 
> is flushed to disk.
> Currently only expired KVs are pruned before flushing, but we can also prune 
> versions if we find at least maxVersions versions in the memstore.
> The same holds for the new minversion feature: If we find at least minVersion 
> versions in the store we can remove all further versions that are expired.
> Generally we should use the same mechanism here that is used for Compaction. 
> I.e. StoreScanner. We only need to add a scanner to Memstore that can scan 
> along the current snapshot.

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