[GitHub] felixcheung commented on a change in pull request #23746: [SPARK-26761][SQL][R] Vectorized R gapply() and gapplyCollect() implementation

[GitBox <gi...@apache.org>]

felixcheung commented on a change in pull request #23746: [SPARK-26761][SQL][R] Vectorized R gapply() and gapplyCollect() implementation
URL: https://github.com/apache/spark/pull/23746#discussion_r255350785
 
 

 ##########
 File path: R/pkg/inst/worker/worker.R
 ##########
 @@ -181,17 +185,35 @@ if (isEmpty != 0) {
                     colNames, computeFunc, data)
        } else {
         # gapply mode
+        outputs <- list()
         for (i in 1:length(data)) {
           # Timing reading input data for execution
           inputElap <- elapsedSecs()
           output <- compute(mode, partition, serializer, deserializer, keys[[i]],
                       colNames, computeFunc, data[[i]])
           computeElap <- elapsedSecs()
-          outputResult(serializer, output, outputCon)
+          if (deserializer == "arrow") {
+            requireNamespace("arrow", quietly = TRUE)
+            outputs[[length(outputs) + 1L]] <- output
+          } else {
+            outputResult(serializer, output, outputCon)
+          }
           outputElap <- elapsedSecs()
           computeInputElapsDiff <-  computeInputElapsDiff + (computeElap - inputElap)
           outputComputeElapsDiff <- outputComputeElapsDiff + (outputElap - computeElap)
         }
+
+        if (deserializer == "arrow") {
+          requireNamespace("arrow", quietly = TRUE)
+          # See https://stat.ethz.ch/pipermail/r-help/2010-September/252046.html
+          # rbind.fill might be an anternative to make it faster if plyr is installed.
+          combined <- do.call("rbind", outputs)
 
 Review comment:
   and be aware of string columns https://github.com/apache/spark/blob/master/R/pkg/inst/worker/worker.R#L35

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services

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