[ 
https://issues.apache.org/jira/browse/SPARK-3051?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Andrew Or updated SPARK-3051:
-----------------------------
    Affects Version/s: 1.0.0

> Support looking-up named accumulators in a registry
> ---------------------------------------------------
>
>                 Key: SPARK-3051
>                 URL: https://issues.apache.org/jira/browse/SPARK-3051
>             Project: Spark
>          Issue Type: Improvement
>          Components: Spark Core
>    Affects Versions: 1.0.0
>            Reporter: Neil Ferguson
>
> This is a proposed enhancement to Spark based on the following mailing list 
> discussion: 
> http://apache-spark-developers-list.1001551.n3.nabble.com/quot-Dynamic-variables-quot-in-Spark-td7450.html.
> This proposal builds on SPARK-2380 (Support displaying accumulator values in 
> the web UI) to allow named accumulables to be looked-up in a "registry", as 
> opposed to having to be passed to every method that need to access them.
> The use case was described well by [~shivaram], as follows:
> Lets say you have two functions you use 
> in a map call and want to measure how much time each of them takes. For 
> example, if you have a code block like the one below and you want to 
> measure how much time f1 takes as a fraction of the task. 
> {noformat}
> a.map { l => 
>    val f = f1(l) 
>    ... some work here ... 
> } 
> {noformat}
> It would be really cool if we could do something like 
> {noformat}
> a.map { l => 
>    val start = System.nanoTime 
>    val f = f1(l) 
>    TaskMetrics.get("f1-time").add(System.nanoTime - start) 
> } 
> {noformat}
> SPARK-2380 provides a partial solution to this problem -- however the 
> accumulables would still need to be passed to every function that needs them, 
> which I think would be cumbersome in any application of reasonable complexity.
> The proposal, as suggested by [~pwendell], is to have a "registry" of 
> accumulables, that can be looked-up by name. 
> Regarding the implementation details, I'd propose that we broadcast a 
> serialized version of all named accumulables in the DAGScheduler (similar to 
> what SPARK-2521 does for Tasks). These can then be deserialized in the 
> Executor. 
> Accumulables are already stored in thread-local variables in the Accumulators 
> object, so exposing these in the registry should be simply a matter of 
> wrapping this object, and keying the accumulables by name (they are currently 
> keyed by ID).



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

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

Reply via email to