nealrichardson commented on a change in pull request #11183:
URL: https://github.com/apache/arrow/pull/11183#discussion_r712480182
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File path: r/R/query-engine.R
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@@ -20,11 +20,36 @@ do_exec_plan <- function(.data) {
final_node <- plan$Build(.data)
tab <- plan$Run(final_node)
+ # If arrange() created $temp_columns, make sure to omit them from the result
+ # We can't currently handle this in the ExecPlan itself because sorting
+ # happens in the end (SinkNode) so nothing comes after it.
if (length(final_node$sort$temp_columns) > 0) {
- # If arrange() created $temp_columns, make sure to omit them from the
result
tab <- tab[, setdiff(names(tab), final_node$sort$temp_columns), drop =
FALSE]
}
+ if (ncol(tab)) {
+ # Apply any column metadata from the original schema, where appropriate
+ original_schema <- source_data(.data)$schema
+ # TODO: do we care about other (non-R) metadata preservation?
Review comment:
We already do discard other metadata when you convert from Arrow to R.
Check out the example parquet file in inst/, for example: it has "pandas"
metadata. I suspect it would be more surprising/alarming if we started
messaging about this metadata all of the sudden.
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