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https://issues.apache.org/jira/browse/HBASE-6032?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13283122#comment-13283122
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Zhihong Yu commented on HBASE-6032:
-----------------------------------

Can someone review the port please ?
                
> Port HFileBlockIndex improvement from HBASE-5987
> ------------------------------------------------
>
>                 Key: HBASE-6032
>                 URL: https://issues.apache.org/jira/browse/HBASE-6032
>             Project: HBase
>          Issue Type: Task
>            Reporter: Zhihong Yu
>            Assignee: Zhihong Yu
>             Fix For: 0.96.0
>
>         Attachments: 6032-ports-5987.txt
>
>
> Excerpt from HBASE-5987:
> First, we propose to lookahead for one more block index so that the 
> HFileScanner would know the start key value of next data block. So if the 
> target key value for the scan(reSeekTo) is "smaller" than that start kv of 
> next data block, it means the target key value has a very high possibility in 
> the current data block (if not in current data block, then the start kv of 
> next data block should be returned. +Indexing on the start key has some 
> defects here+) and it shall NOT query the HFileBlockIndex in this case. On 
> the contrary, if the target key value is "bigger", then it shall query the 
> HFileBlockIndex. This improvement shall help to reduce the hotness of 
> HFileBlockIndex and avoid some unnecessary IdLock Contention or Index Block 
> Cache lookup.
> This JIRA is to port the fix to HBase trunk, etc.

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