[jira] [Commented] (SPARK-7251) Perform sequential scan when iterating over entries in BytesToBytesMap

["Chen Song (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-7251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14522977#comment-14522977 ] 

Chen Song commented on SPARK-7251:
----------------------------------

Can the key could be empty? If we allow the key could be zero, it's impossible to deal the useless memory of the end page. Because I don't know if it's at the end of the page or just the key is empty. Of couse I have to setMemory to zero. 

> Perform sequential scan when iterating over entries in BytesToBytesMap
> ----------------------------------------------------------------------
>
>                 Key: SPARK-7251
>                 URL: https://issues.apache.org/jira/browse/SPARK-7251
>             Project: Spark
>          Issue Type: Improvement
>          Components: Spark Core
>            Reporter: Josh Rosen
>
> In BytesToBytesMap, {{iterator()}} iterates in order of set bits in the bitmap, but it would be faster to iterate directly through the data pages, since this will result in less random memory access.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org