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https://issues.apache.org/jira/browse/HBASE-4683?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13168984#comment-13168984
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Phabricator commented on HBASE-4683:
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mbautin has commented on the revision "[jira] [HBASE-4683] Always cache index
and bloom blocks".
INLINE COMMENTS
src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderV2.java:293
Compactions mostly consist of continuous reads and should not do a lot of
seeks. But yes, this will cache index/bloom blocks even in case of compactions.
I guess I could add a unit test to make sure we really don't utilize the block
index during compactions, and we can explicitly disable them here. Or we could
leave it as it is in case compactions do use the block index in a limited way
(need to find out if that is the case).
@jdcryans: any thoughts/suggestions on this?
REVISION DETAIL
https://reviews.facebook.net/D807
> Always cache index and bloom blocks
> -----------------------------------
>
> Key: HBASE-4683
> URL: https://issues.apache.org/jira/browse/HBASE-4683
> Project: HBase
> Issue Type: New Feature
> Reporter: Lars Hofhansl
> Assignee: Mikhail Bautin
> Priority: Minor
> Fix For: 0.92.0, 0.94.0
>
> Attachments: 4683-v2.txt, 4683.txt, D807.1.patch, D807.2.patch,
> HBASE-4683-0.92-v2.patch, HBASE-4683-v3.patch
>
>
> This would add a new boolean config option: hfile.block.cache.datablocks
> Default would be true.
> Setting this to false allows HBase in a mode where only index blocks are
> cached, which is useful for analytical scenarios where a useful working set
> of the data cannot be expected to fit into the (aggregate) cache.
> This is the equivalent of setting cacheBlocks to false on all scans
> (including scans on behalf of gets).
> I would like to get a general feeling about what folks think about this.
> The change itself would be simple.
> Update (Mikhail): we probably don't need a new conf option. Instead, we will
> make index blocks cached by default.
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