[GitHub] [arrow] jonkeane commented on a change in pull request #11783: ARROW-14894: [R] Integer overflow in write_parquet chunk size calculation

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jonkeane commented on a change in pull request #11783:
URL: https://github.com/apache/arrow/pull/11783#discussion_r762070759



##########
File path: r/tests/testthat/test-parquet.R
##########
@@ -311,3 +311,7 @@ test_that("ParquetFileWrite chunk_size defaults", {
       expect_error(reader$ReadRowGroup(2), "Some index in row_group_indices")
     })
 })
+
+test_that("ParquetFileWrite chunk_size calculation doesn't have integer overflow issues (ARROW-14894)", {
+  expect_equal(calculate_chunk_size(31869547, 108, 2.5e8, 200), 2451504)

Review comment:
       ```suggestion
     expect_equal(calculate_chunk_size(31869547, 108, 2.5e8, 200), 2451504)
     
     # we can set the target cells per group, and it rounds appropriately
     expect_equal(calculate_chunk_size(100, 1, 25), 25)
     expect_equal(calculate_chunk_size(101, 1, 25), 26)
     
     # but our max_chunks is respected
     expect_equal(calculate_chunk_size(101, 1, 25, 2), 51)
   ```
   
   These are kinda-sorta the same tests as above, so we don't _need_ to include them but I find these a bit easier to reason about (and certainly easier to test than constructing a whole dataset!)

##########
File path: r/R/parquet.R
##########
@@ -608,3 +593,28 @@ ParquetArrowReaderProperties <- R6Class("ParquetArrowReaderProperties",
 ParquetArrowReaderProperties$create <- function(use_threads = option_use_threads()) {
   parquet___arrow___ArrowReaderProperties__Make(isTRUE(use_threads))
 }
+
+calculate_chunk_size <- function(rows,  columns,
+  target_cells_per_group = getOption("arrow.parquet_cells_per_group", 2.5e8),
+  max_chunks = getOption("arrow.parquet_max_chunks", 200)
+  ){

Review comment:
       ```suggestion
     ) {
   ```




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