[jira] [Commented] (HBASE-9000) Linear reseek in Memstore

["Lars Hofhansl (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-9000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13930909#comment-13930909 ] 

Lars Hofhansl commented on HBASE-9000:
--------------------------------------

HBASE-9778 is committed now. It allows a configurable optional look ahead in ExplicitColumn tracker. Hence it'll do it in both Memstore and StoreScanner. I did look into doing that in StoreFileScanner, but most of the time of a reseek is spent before we even get to StoreFileScanner (checking whether we are forward seeking, checking whether we're still on the same block, seeking every HFile forward, etc).


> Linear reseek in Memstore
> -------------------------
>
>                 Key: HBASE-9000
>                 URL: https://issues.apache.org/jira/browse/HBASE-9000
>             Project: HBase
>          Issue Type: Improvement
>          Components: Performance
>    Affects Versions: 0.89-fb
>            Reporter: Shane Hogan
>            Priority: Minor
>             Fix For: 0.89-fb
>
>         Attachments: hbase-9000-benchmark-program.patch, hbase-9000-port-fb.patch, hbase-9000.patch
>
>
> This is to address the linear reseek in MemStoreScanner. Currently reseek iterates over the kvset and the snapshot linearly by just calling next repeatedly. The new solution is to do this linear seek up to a configurable maximum amount of times then if the seek is not yet complete fall back to logarithmic seek.



--
This message was sent by Atlassian JIRA
(v6.2#6252)