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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