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From "Anoop Sam John (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-14826) Small improvement in KVHeap seek() API
Date Fri, 20 Nov 2015 11:21:11 GMT

    [ https://issues.apache.org/jira/browse/HBASE-14826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15015620#comment-15015620
] 

Anoop Sam John commented on HBASE-14826:
----------------------------------------

Ya  in real scan case we do seek but then also it is actually fwd only.  I was just asking
in generic as we have seek back support as such here.

> Small improvement in KVHeap seek() API
> --------------------------------------
>
>                 Key: HBASE-14826
>                 URL: https://issues.apache.org/jira/browse/HBASE-14826
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: ramkrishna.s.vasudevan
>            Assignee: ramkrishna.s.vasudevan
>            Priority: Minor
>         Attachments: HBASE-14826.patch
>
>
> Currently in seek/reseek() APIs we tend to do lot of priorityqueue related operations.
We initially add the current scanner to the heap, then poll and again add the scanner back
if the seekKey is greater than the topkey in that scanner. Since the KVs are always going
to be in increasing order and in ideal scan flow every seek/reseek is followed by a next()
call it should be ok if we start with checking the current scanner and then do a poll to get
the next scanner. Just avoid the initial PQ.add(current) call. This could save some comparisons.




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