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https://issues.apache.org/jira/browse/CASSANDRA-6078?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Oleg Anastasyev updated CASSANDRA-6078:
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Description:
Memtable.getLiveSize does not honours liveRatio the correct way:
allocator.get**Size() return sizes allocated only by name and columns data
(i.e. no liveRatio applied); but conditions, which cap estimated size, compare
it with estimatedSize, already multiplied by liveRatio.
If liveRatio is big enough (i've seen >11 on our dataset), this leads to huge
estimation errors and even to OutOfMemory, because MeteredFlusher
underestimates memtables sizes.
was:
Memtable.getLiveSize does not honours liveRatio the correct way:
allocator.get**Size() return sizes allocated only by name and columns data
(i.e. no liveRatio applied); but conditions, which cap estimated size, compare
it with estimatedSize, already multiplied by liveRatio.
If liveRatio is big enough (i've seen >11 on our dataset), this leads to huge
estimation errors and even to OutOfMemory, because MeteredFlusher is
underestimates memtables sizes.
> Wrong memtable size estimation: liveRatio is not honored in edge cases
> ----------------------------------------------------------------------
>
> Key: CASSANDRA-6078
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6078
> Project: Cassandra
> Issue Type: Bug
> Reporter: Oleg Anastasyev
> Attachments: Memtable-getLiveSize.diff
>
>
> Memtable.getLiveSize does not honours liveRatio the correct way:
> allocator.get**Size() return sizes allocated only by name and columns data
> (i.e. no liveRatio applied); but conditions, which cap estimated size,
> compare it with estimatedSize, already multiplied by liveRatio.
> If liveRatio is big enough (i've seen >11 on our dataset), this leads to huge
> estimation errors and even to OutOfMemory, because MeteredFlusher
> underestimates memtables sizes.
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