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https://issues.apache.org/jira/browse/HBASE-4241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lars Hofhansl updated HBASE-4241:
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Attachment: 4241.txt
Here's a sketch for a patch.
Basically the KVs of the memstore's snapshot are wrapped in a scanner and then
passed for a new StoreScanner.
So we use the same logic as in compactions here, which is good.
The reasoning why this is correct goes as follows:
If maxVersion=N and we find more than N versions in the memstore we safely
avoid writing all further versions.
Same for minVersions, if minversions=N and we find at least N versions in the
memstore we can avoid writing all further expired versions.
> 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: Sub-task
> Components: regionserver
> Affects Versions: 0.92.0
> Reporter: Lars Hofhansl
> Priority: Minor
> Attachments: 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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