hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Liang Xie (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-7845) optimize hfile index key
Date Fri, 22 Mar 2013 03:11:15 GMT

    [ https://issues.apache.org/jira/browse/HBASE-7845?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13609849#comment-13609849

Liang Xie commented on HBASE-7845:

Hi [~stack], the expected blocks read number being reduced because:
Without patch, the search for row/cf1/col5 is done by looking for "row/cf1/col5/LATEST_TIMESTAMP/...",
and this will land us in previous block(col4), found mis-matched(blockseek return 1), then
advance to current block(issued a HFileScanner.next operation).

With patch, due to faked index key effect, we locate the current block(col5) directly and
blockSeek return -2, then we don't need to request HFileScanner.next, which will call readNextDataBlock

Hope it's clear, sorry for my poor english:)
> optimize hfile index key
> ------------------------
>                 Key: HBASE-7845
>                 URL: https://issues.apache.org/jira/browse/HBASE-7845
>             Project: HBase
>          Issue Type: Improvement
>          Components: HFile
>    Affects Versions: 0.96.0
>            Reporter: Liang Xie
>            Assignee: Liang Xie
>             Fix For: 0.98.0
>         Attachments: HBASE-7845.txt, HBASE-7845-v2.txt, HBASE-7845-v3.txt, HBASE-7845-v4.txt,
HBASE-7845-v5.txt, HBASE-7845-v6.txt, HBASE-7845-v7.txt, HBASE-7845-v8.txt
> Leveldb uses ByteWiseComparatorImpl::FindShortestSeparator() & FindShortSuccessor()
to reduce index key size, it would be helpful under special conditions.

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

View raw message