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https://issues.apache.org/jira/browse/HBASE-11581?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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stack updated HBASE-11581:
--------------------------
Resolution: Invalid
Release Note: (was: Add hbase.combinedblockcache.l2.null configuration.
When set to true, BlockCache uses CombinedBlockCache where L1 is instance of
LruBlockCache carrying META blocks and L2 is null: i.e. DATA blocks are fetched
each time.)
Status: Resolved (was: Patch Available)
Resolving as won't fix. I can get the desired effect -- caching of META blocks
only and NOT caching DATA blocks -- by setting BLOCKCACHE => 'false' (since
HBASE-4683 "Always cache index and bloom blocks"). Testing I was confused by
metrics showing DATA blocks count but the number was a persist from before the
configuration change (Need to look into why metric not reset....that is another
issue).
> Add option so CombinedBlockCache L2 can be null (fscache)
> ---------------------------------------------------------
>
> Key: HBASE-11581
> URL: https://issues.apache.org/jira/browse/HBASE-11581
> Project: HBase
> Issue Type: New Feature
> Components: BlockCache
> Reporter: stack
> Assignee: stack
> Priority: Minor
> Labels: beginner, beginners
> Attachments: 11581.txt
>
>
> Add option, mostly for comparison's sake, that allows a deploy orchestrated
> by CombinedBlockCache such that its L1 is LruBlockCache for META blocks but
> DATA blocks are fetched each time (we don't try and cache them, no blockcache
> churn).
> In operation, i can see fscache coming around to cover the fetched DATA
> blocks such that if the DATA blocks fit in fscache, seeks go to zero.
> This setup for sure runs slower. Will publish numbers elsewhere. Meantime,
> here is a patch to enable this option.
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