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https://issues.apache.org/jira/browse/HBASE-14906?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15039630#comment-15039630
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Yu Li commented on HBASE-14906:
-------------------------------
{quote}
So there is no exact lower bound in global config?
{quote}
Yes, there's only a "minimum lower bound" in global config, or say the default
value for lower bound would be "dynamic" and table-specific now instead of any
fixed value, unless the auto computed one is smaller than the minimum config.
After the change there's no way for user to specify a _uniform small_ lower
bound for *all* tables any more, which is also unnecessary IMHO. Expert user
who wants to specify a smaller lower bound for any specified table could still
achieve the goal by setting
{{hbase.hregion.percolumnfamilyflush.size.lower.bound}} in table descriptor
Feel free to let me know if any concern here. Thanks.
> Improvements on FlushLargeStoresPolicy
> --------------------------------------
>
> Key: HBASE-14906
> URL: https://issues.apache.org/jira/browse/HBASE-14906
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 2.0.0
> Reporter: Yu Li
> Assignee: Yu Li
> Fix For: 2.0.0
>
> Attachments: HBASE-14906.patch, HBASE-14906.v2.patch,
> HBASE-14906.v3.patch, HBASE-14906.v4.patch, HBASE-14906.v4.patch
>
>
> When checking FlushLargeStoragePolicy, found below possible improving points:
> 1. Currently in selectStoresToFlush, we will do the selection no matter how
> many actual families, which is not necessary for one single family
> 2. Default value for hbase.hregion.percolumnfamilyflush.size.lower.bound
> could not fit in all cases, and requires user to know details of the
> implementation to properly set it. We propose to use
> "hbase.hregion.memstore.flush.size/column_family_number" instead:
> {noformat}
> <property>
> <name>hbase.hregion.percolumnfamilyflush.size.lower.bound</name>
> <value>16777216</value>
> <description>
> If FlushLargeStoresPolicy is used and there are multiple column families,
> then every time that we hit the total memstore limit, we find out all the
> column families whose memstores exceed a "lower bound" and only flush them
> while retaining the others in memory. The "lower bound" will be
> "hbase.hregion.memstore.flush.size / column_family_number" by default
> unless value of this property is larger than that. If none of the families
> have their memstore size more than lower bound, all the memstores will be
> flushed (just as usual).
> </description>
> </property>
> {noformat}
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