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https://issues.apache.org/jira/browse/HBASE-27805?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zheng Wang updated HBASE-27805:
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Description:
The default size of chunk is 2MB, when we use G1, if heapRegionSize equals 4MB,
these chunks are allocated as humongous objects, exclusively allocating one
region, then the remaining 2MB become memory fragement.
Lots of memory fragement may leading to fullgc even if the percent of used heap
not high enough.
I have tested to reduce the chunk size to 2047k, there was no repeat of the
above.
was:
The default size of chunk is 2MB, when we use G1, if heapRegionSize equals 4MB,
these chunks are allocated as humongous objects, exclusively allocating one
region, then the remaining 2MB become memory fragement.
Lots of memory fragement may leading to fullgc even if the percent of used heap
not high enough.
> The chunk created by mslab may cause memory fragement and leading to fullgc
> ---------------------------------------------------------------------------
>
> Key: HBASE-27805
> URL: https://issues.apache.org/jira/browse/HBASE-27805
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Reporter: Zheng Wang
> Assignee: Zheng Wang
> Priority: Major
> Attachments: chunksize-2047k.png, chunksize-2048k-fullgc.png
>
>
> The default size of chunk is 2MB, when we use G1, if heapRegionSize equals
> 4MB, these chunks are allocated as humongous objects, exclusively allocating
> one region, then the remaining 2MB become memory fragement.
> Lots of memory fragement may leading to fullgc even if the percent of used
> heap not high enough.
> I have tested to reduce the chunk size to 2047k, there was no repeat of the
> above.
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