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https://issues.apache.org/jira/browse/HBASE-6312?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13407348#comment-13407348
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Jean-Daniel Cryans commented on HBASE-6312:
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bq. According to your suggestion, shall we need to make that gap (between the
minimum and acceptable factor) configurable at least?
We can, I just don't know how useful that's gonna be. It can hardly be worse
than it is right now tho :)
bq. Maybe We should evict only after cache size is large than
hfile.block.cache.size, and allow ~15% burstiness before blocking.
It seems to me that we'd just have the reverse problem.
The real problem here is that LruBlockCache won't let us use exactly the amount
of memory we want, it's like driving a car and the best you can do is steering
all the way left or all the way right because keeping it centered would require
too much effort.
Right now I'd be in favor of setting the acceptable factor to 99% and the
minimum at 95% since it's really hard to overflow and there's no blocking. We
can make the minimum configurable so that if someone sees that it's evicting
too often they can tune it down.
> Make BlockCache eviction thresholds configurable
> ------------------------------------------------
>
> Key: HBASE-6312
> URL: https://issues.apache.org/jira/browse/HBASE-6312
> Project: HBase
> Issue Type: Improvement
> Components: io
> Affects Versions: 0.94.0
> Reporter: Jie Huang
> Priority: Minor
> Attachments: hbase-6312.patch
>
>
> Some of our customers found that tuning the BlockCache eviction thresholds
> made test results different in their test environment. However, those
> thresholds are not configurable in the current implementation. The only way
> to change those values is to re-compile the HBase source code. We wonder if
> it is possible to make them configurable.
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