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https://issues.apache.org/jira/browse/HBASE-19095?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16224169#comment-16224169
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Eshcar Hillel commented on HBASE-19095:
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Basic mode does not use StoreScanner. Basic applies two kinds of steps - a
flattening step and a merge step.
A merge step creates a MemStoreMergerSegmentsIterator. This iterator manages a
KeyValueHeap it uses it to merge the index of several segments, and does not
drop any cell.
A flattening step simply uses a segment scanner to create a flat index, and
does not drop any cell.
I would not open these to CP hooks.
Other modes (like Eager, and Adaptive which I am about to commit to trunk) may
apply a compact step which imitates disk data compaction in-memory.
A compact step creates a MemStoreCompactorSegmentsIterator which uses a
StoreScanner as described above.
Here, I agree there is room to give the user control on the number of versions
to keep, TTL etc.
> Add CP hooks in RegionObserver for in memory compaction
> -------------------------------------------------------
>
> Key: HBASE-19095
> URL: https://issues.apache.org/jira/browse/HBASE-19095
> Project: HBase
> Issue Type: Sub-task
> Components: Coprocessors
> Reporter: Duo Zhang
> Fix For: 2.0.0-beta-1
>
>
> This is a hole in our CP hooks.
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