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Posted to jira@arrow.apache.org by "José F (Jira)" <ji...@apache.org> on 2022/01/20 20:55:00 UTC

[jira] [Created] (ARROW-15397) Problem with Join in apache arrow in R

José F created ARROW-15397:
------------------------------

             Summary: Problem with Join in apache arrow in R
                 Key: ARROW-15397
                 URL: https://issues.apache.org/jira/browse/ARROW-15397
             Project: Apache Arrow
          Issue Type: Bug
          Components: R
    Affects Versions: 6.0.1
            Reporter: José F
             Fix For: 6.0.2


Hi dear arrow developers. I tested inner_join with arrow R package but R crashed, this is my example with toy dataset iris:

 

data(iris)
write.csv(iris, "iris.csv") # write csv file

# write parket file with write_chunk_data (at the end for  interested users)

walk("C:/Users/Stats/Desktop/ejemplo_join/iris.csv",
     write_chunk_data, "C:/Users/Stats/Desktop/ejemplo_join/parquet", chunk_size = 50)

 

iris_arrow <- open_dataset("parquet")

df1_arrow <- iris_arrow %>% select(`...1`, Sepal.Length, Sepal.Width, Petal.Length) 
df2_arrow <-   iris_arrow %>% select(`...1`, Petal.Width, Species,) d

df <- tabla1_arrow %>% inner_join(tabla2_arrow, by = "...1") %>% 

group_by(Species) %>% summarise(prom = mean(Sepal.Length)) %>% collect()
print(df)

 

 

# If you want to check function to write parquet file from a csv:

 write_chunk_data <- function(data_path, output_dir, chunk_size = 1000000) {
  #If the output_dir do not exist, it is created
  if (!fs::dir_exists(output_dir)) fs::dir_create(output_dir)
  #It gets the name of the file
  data_name <- fs::path_ext_remove(fs::path_file(data_path))
  #It sets the chunk_num to 0
  chunk_num <- 0
  #Read the file using vroom
  data_chunk <- vroom::vroom(data_path)
  #It gets the variable names
  data_names <- names(data_chunk)
  #It gets the number of rows
  rows<-nrow(data_chunk)
  
  #The following loop creates a parquet file for every [chunk_size] rows
  repeat{
    #It checks if we are over the max rows
    if(rows>(chunk_num+1)*chunk_size){
      arrow::write_parquet(data_chunk[(chunk_num*chunk_size+1):((chunk_num+1)*chunk_size),], 
                           fs::path(output_dir, glue::glue("\{data_name}-\{chunk_num}.parquet")))
    }
    else{
      arrow::write_parquet(data_chunk[(chunk_num*chunk_size+1):rows,], 
                           fs::path(output_dir, glue::glue("\{data_name}-\{chunk_num}.parquet"))) 
      break
    }
    chunk_num <- chunk_num + 1
  }
   
  #This is to recover some memory and space in the disk
  rm(data_chunk)
  tmp_file <- tempdir()
  files <- list.files(tmp_file, full.names = T, pattern = "^vroom")
  file.remove(files)
}

 



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