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https://issues.apache.org/jira/browse/HBASE-10291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Arjen Roodselaar updated HBASE-10291:
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Attachment: per-cf-L2-stats.patch
> Schema aware L2 BucketCache metrics
> -----------------------------------
>
> Key: HBASE-10291
> URL: https://issues.apache.org/jira/browse/HBASE-10291
> Project: HBase
> Issue Type: New Feature
> Components: regionserver
> Affects Versions: 0.89-fb
> Reporter: Arjen Roodselaar
> Assignee: Arjen Roodselaar
> Priority: Minor
> Fix For: 0.89-fb
>
> Attachments: per-cf-L2-stats.patch
>
>
> This patch adds per-column family L2 cache metrics. In order to make this
> happen the following needed to change:
> The L2 cache deals with raw block data. However, in order to keep the size
> metrics for different CF's and block types valid the cache needs to know
> about the block type. In the BlockCache this is achieved by making the
> HFileBlock implement SchemaAware and augment the HFileBlock with the
> appropriate data before adding it to the cache. In order to do the same for
> the L2 cache RawHFileBlock were added, and the BucketEntry was made to
> implement SchemaAware.
> This led to an interesting problem, as the L2 cache is possibly used by
> readers and writers who do not have the SchemaAware data. In order to work
> around this a lightweight facade wrapping CacheConfig and the L2 cache can be
> instantiated and passed down instead of the actual L2 cache object. This
> L2CacheAgent is SchemaAware and can add the schema data to the
> RawHFileBlock's before handing them over to the cache. I feel the
> L2CacheAgent is still a work in progress as it could potentially centralize
> the cache policy and allow all cache decisions to be removed from HFile- and
> block readers and writers.
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