[jira] [Commented] (SPARK-36420) Use `isEmpty` to improve performance in Pregel's superstep

["Apache Spark (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SPARK-36420?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17393627#comment-17393627 ] 

Apache Spark commented on SPARK-36420:
--------------------------------------

User 'StefanXiepj' has created a pull request for this issue:
https://github.com/apache/spark/pull/33648

> Use `isEmpty` to improve performance in Pregel's superstep
> ----------------------------------------------------------
>
>                 Key: SPARK-36420
>                 URL: https://issues.apache.org/jira/browse/SPARK-36420
>             Project: Spark
>          Issue Type: Improvement
>          Components: GraphX
>    Affects Versions: 2.4.7
>            Reporter: xiepengjie
>            Priority: Minor
>             Fix For: 3.3.0
>
>
> When I was running `Graphx.connectedComponents` with 20+ billion vertices and edges, I found that count is very slow.
> {code:java}
> object Pregel extends Logging {
>   ...
>   def apply[VD: ClassTag, ED: ClassTag, A: ClassTag] (...): Graph[VD, ED] = {
>     ...
>     // Maybe messages.isEmpty() is better than messages.count()
>     var activeMessages = messages.count()
>     // Loop
>     var prevG: Graph[VD, ED] = null
>     var i = 0
>     while (activeMessages > 0 && i < maxIterations) {
>       ...
>       activeMessages = messages.count()
>       ...
>     }
>     ...
>     g
>   } // end of apply
> } // end of class Pregel
> {code}
> Maybe we only need an action operator here and active-messages are not empty, so we don’t need to use count, it’s better to use isEmpty. I verified it and it worked very well.
>  



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

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