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https://issues.apache.org/jira/browse/HBASE-15016?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15150727#comment-15150727
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stack commented on HBASE-15016:
-------------------------------
[~eshcar] Thanks. My fault for not getting to this sooner.
Patch LGTM. Only odd thing is calling through to Stores every time we up the
size of the memstore:
Changing....
2885 long newSize = this.addAndGetGlobalMemstoreSize(addedSize);
2886 if (isFlushSize(newSize)) {
2887 requestFlush();
2888 }
to
2901 this.addAndGetGlobalMemstoreSize(addedSize);
2902 requestFlushIfNeeded();
Add least pass the value returned by addAndGetGlobalMemstoreSize to
requestFlushIfNeeded so we don't need to get it again (avoid the extra volatile
read)
Shouldn't RegionServicesForStores be an Interface (The HRegion does the
implementation, at least at first?)
There is only one sequenceid in the system so no need of the WAL qualifier here
getWalSequenceId (in fact sequenceid comes from mvcc even when it comes up out
of WAL).
We should not have getSequenceId as a public method on Region. It is too
dangerous exposing it so. We can not guarantee at the Region level that the
sequenceid we give out at that level has all writes with less sequenceids acked
and persisted to the WAL.
Otherwise, the patch is great.
> StoreServices facility in Region
> --------------------------------
>
> Key: HBASE-15016
> URL: https://issues.apache.org/jira/browse/HBASE-15016
> Project: HBase
> Issue Type: Sub-task
> Reporter: Eshcar Hillel
> Assignee: Eshcar Hillel
> Attachments: HBASE-15016-V01.patch, HBASE-15016-V02.patch,
> HBASE-15016-V03.patch, HBASE-15016-V04.patch, Regioncounters.pdf,
> suggestion.patch
>
>
> The default implementation of a memstore ensures that between two flushes the
> memstore size increases monotonically. Supporting new memstores that store
> data in different formats (specifically, compressed), or that allows to
> eliminate data redundancies in memory (e.g., via compaction), means that the
> size of the data stored in memory can decrease even between two flushes. This
> requires memstores to have access to facilities that manipulate region
> counters and synchronization.
> This subtasks introduces a new region interface -- StoreServices, through
> which store components can access these facilities.
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