[ 
https://issues.apache.org/jira/browse/HBASE-9000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13809870#comment-13809870
 ] 

Chao Shi commented on HBASE-9000:
---------------------------------

bq. 'reseek to next row' gets slower with patch. If "linear.search.limit" is 
lowered, would the slow down be less ?

Yes, the optimal value should vary case by case. I think a default value of 5 
should not add much observable overhead.

I think a long-term solution would be implementing our own version of lock-free 
skip-list, where we can access its higher-level of next pointers (i.e. to skip) 
from the current position. This patch could be a temporary solution for now, as 
it is very simple.

> Linear reseek in Memstore
> -------------------------
>
>                 Key: HBASE-9000
>                 URL: https://issues.apache.org/jira/browse/HBASE-9000
>             Project: HBase
>          Issue Type: Improvement
>    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
>
>
> 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
(v6.1#6144)

Reply via email to