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https://issues.apache.org/jira/browse/PHOENIX-6655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17637253#comment-17637253
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Istvan Toth commented on PHOENIX-6655:
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This is a different case than PHOENIX-4575
KEEP_DELETED_CELLS affects the data retained.
CACHE_DATA_ON_WRITE is purely a performance optimization.
I cannot imagine a realistic scenario where you wouldn't want to have this
setting for sequences.
> SYSTEM.SEQUENCE should have CACHE_DATA_ON_WRITE set to true
> -----------------------------------------------------------
>
> Key: PHOENIX-6655
> URL: https://issues.apache.org/jira/browse/PHOENIX-6655
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Geoffrey Jacoby
> Assignee: Gourab Taparia
> Priority: Major
>
> High volume use cases of Phoenix sequences need to write to the same row of
> SYSTEM.SEQUENCE very frequently, but each time we write, the block cache that
> row is in is invalidated and has to be loaded again.
> [~rushabh.shah] was looking at a case in our environment where a sequence was
> being used heavily and found lots of time spent reading the HFiles for the
> same Get of the sequence row within the SequenceRegionObserver increment
> coproc.
> [~apurtell] pointed out offline that HColumnDescriptor has a property,
> CACHE_DATA_ON_WRITE that keeps caches updated when a value is flushed. This
> should help improve contention on sequence increments.
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