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https://issues.apache.org/jira/browse/HBASE-11331?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14031006#comment-14031006
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Nick Dimiduk commented on HBASE-11331:
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Decompressed blocks aren't stored anywhere in the patch posted. This patch,
just as current master code, decompressed an HFileBlock into an on-heap
ByteBuffer. There's no additional cache layer for decompressed blocks as it
stands currently; they're decompressed, consumed, and thrown away.
HFileReaderV2$AbstractScannerV2 keeps a reference to the current block, so a
single GET shouldn't pay the cost of decompression multiple times, but I need
to confirm this is true.
> [blockcache] lazy block decompression
> -------------------------------------
>
> Key: HBASE-11331
> URL: https://issues.apache.org/jira/browse/HBASE-11331
> Project: HBase
> Issue Type: Improvement
> Components: regionserver
> Reporter: Nick Dimiduk
> Assignee: Nick Dimiduk
> Attachments: HBASE-11331.00.patch
>
>
> Maintaining data in its compressed form in the block cache will greatly
> increase our effective blockcache size and should show a meaning improvement
> in cache hit rates in well designed applications. The idea here is to lazily
> decompress/decrypt blocks when they're consumed, rather than as soon as
> they're pulled off of disk.
> This is related to but less invasive than HBASE-8894.
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