ahmed-mez commented on code in PR #18906:
URL: https://github.com/apache/datafusion/pull/18906#discussion_r2559265016
##########
datafusion/physical-plan/src/aggregates/group_values/row.rs:
##########
@@ -206,29 +233,43 @@ impl GroupValues for GroupValuesRows {
output
}
EmitTo::First(n) => {
- let groups_rows = group_values.iter().take(n);
- let output = self.row_converter.convert_rows(groups_rows)?;
- // Clear out first n group keys by copying them to a new Rows.
- // TODO file some ticket in arrow-rs to make this more
efficient?
- let mut new_group_values = self.row_converter.empty_rows(0, 0);
- for row in group_values.iter().skip(n) {
- new_group_values.push(row);
- }
- std::mem::swap(&mut new_group_values, &mut group_values);
-
- self.map.retain(|(_exists_hash, group_idx)| {
- // Decrement group index by n
- match group_idx.checked_sub(n) {
- // Group index was >= n, shift value down
- Some(sub) => {
- *group_idx = sub;
- true
- }
- // Group index was < n, so remove from table
- None => false,
+ if self.drain_mode {
+ let start = self.emission_offset;
+ let end = std::cmp::min(start + n,
group_values.num_rows());
+ let iter = group_values.iter().skip(start).take(end -
start);
+ let output = self.row_converter.convert_rows(iter)?;
+ self.emission_offset = end;
+ if self.emission_offset == group_values.num_rows() {
+ group_values.clear();
+ self.emission_offset = 0;
Review Comment:
I think it's needed for `emit_early_if_necessary()` for `Partial` mode with
memory pressure and `group_ordering.emit_to()` when input is sorted or
partially sorted. Those 2 cases can trigger incremental / early emission.
I added a test case for sorted input
https://github.com/apache/datafusion/pull/18906/commits/c4903b6f46ec45c0a55c3bdc71f6c8cc4f95728d
that triggers that path.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
