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https://issues.apache.org/jira/browse/HBASE-9915?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13835591#comment-13835591
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Hudson commented on HBASE-9915:
-------------------------------
SUCCESS: Integrated in hbase-0.96-hadoop2 #137 (See
[https://builds.apache.org/job/hbase-0.96-hadoop2/137/])
HBASE-10058 Test for HBASE-9915 (avoid reading index blocks) (larsh: rev
1546660)
*
/hbase/branches/0.96/hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestBlocksScanned.java
> Performance: isSeeked() in EncodedScannerV2 always returns false
> ----------------------------------------------------------------
>
> Key: HBASE-9915
> URL: https://issues.apache.org/jira/browse/HBASE-9915
> Project: HBase
> Issue Type: Bug
> Components: Scanners
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Labels: performance
> Fix For: 0.98.0, 0.96.1, 0.94.14
>
> Attachments: 9915-0.94.txt, 9915-trunk-v2.txt, 9915-trunk-v2.txt,
> 9915-trunk.txt, profile.png
>
>
> While debugging why reseek is so slow I found that it is quite broken for
> encoded scanners.
> The problem is this:
> AbstractScannerV2.reseekTo(...) calls isSeeked() to check whether scanner was
> seeked or not. If it was it checks whether the KV we want to seek to is in
> the current block, if not it always consults the index blocks again.
> isSeeked checks the blockBuffer member, which is not used by EncodedScannerV2
> and thus always returns false, which in turns causes an index lookup for each
> reseek.
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