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https://issues.apache.org/jira/browse/SPARK-16785?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15398312#comment-15398312
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Clark Fitzgerald edited comment on SPARK-16785 at 7/28/16 10:51 PM:
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[~shivaram] and I have had some email correspondence on this: 

bq. parallelizing data containing binary values: To create a SparkDataFrame 
from a local R data frame we first convert it to a list of rows and then 
partition the rows. This happens on the driver 1. The rows are then 
reconstructed back into a data.frame on the workers 2. The rbind.data.frame 
fails for the the binary example. I've created a small reproducible example at 
https://gist.github.com/shivaram/2f07208a8ebc0832098328fa0a3fac9d

1 
https://github.com/apache/spark/blob/0869b3a5f028b64c2da511e70b02ab42f65fc949/R/pkg/R/SQLContext.R#L209
2 
https://github.com/apache/spark/blob/0869b3a5f028b64c2da511e70b02ab42f65fc949/R/pkg/inst/worker/worker.R#L39


was (Author: clarkfitzg):
[~shivaram] and I have had some email correspondence on this: 

bq. parallelizing data containing binary values: To create a SparkDataFrame 
from a local R data frame we first convert it to a list of rows and then 
partition the rows. This happens on the driver 1. The rows are then 
reconstructed back into a data.frame on the workers 2. The rbind.data.frame 
fails for the the binary example. I've created a small reproducible example at 
https://gist.github.com/shivaram/2f07208a8ebc0832098328fa0a3fac9d

1 
https://github.com/apache/spark/blob/0869b3a5f028b64c2da511e70b02ab42f65fc949/R/pkg/R/SQLContext.R#L209
2 
https://github.com/apache/spark/blob/0869b3a5f028b64c2da511e70b02ab42f65fc949/R/pkg/inst/worker/worker.R#L39

To fix this I propose to treat the rows as a list of dataframes instead of as a 
list of lists:

{{rowlist = split(df, 1:nrow(df))}}
{{df2 = do.call(rbind, rowlist)}}



> dapply doesn't return array or raw columns
> ------------------------------------------
>
>                 Key: SPARK-16785
>                 URL: https://issues.apache.org/jira/browse/SPARK-16785
>             Project: Spark
>          Issue Type: Bug
>          Components: SparkR
>    Affects Versions: 2.0.0
>         Environment: Mac OS X
>            Reporter: Clark Fitzgerald
>            Priority: Minor
>
> Calling SparkR::dapplyCollect with R functions that return dataframes 
> produces an error. This comes up when returning columns of binary data- ie. 
> serialized fitted models. Also happens when functions return columns 
> containing vectors.
> The error message:
> R computation failed with
>  Error in (function (..., deparse.level = 1, make.row.names = TRUE, 
> stringsAsFactors = default.stringsAsFactors())  :
>   invalid list argument: all variables should have the same length
> Reproducible example: 
> https://github.com/clarkfitzg/phd_research/blob/master/ddR/spark/sparkR_dapplyCollect7.R
> Relates to SPARK-16611



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