mustafasrepo commented on code in PR #6671:
URL: https://github.com/apache/arrow-datafusion/pull/6671#discussion_r1231800606
##########
datafusion/core/tests/user_defined_aggregates.rs:
##########
@@ -79,15 +98,41 @@ async fn test_udaf_as_window() {
];
assert_batches_eq!(expected, &execute(&ctx, sql).await);
// aggregate over the entire window function call update_batch
- assert!(counters.update_batch());
- assert!(!counters.retract_batch());
+ assert!(test_state.update_batch());
+ assert!(!test_state.retract_batch());
}
/// User defined aggregate used as a window function with a window frame
#[tokio::test]
async fn test_udaf_as_window_with_frame() {
- let TestContext { ctx, counters } = TestContext::new();
+ let TestContext { ctx, test_state } = TestContext::new();
+ let sql = "SELECT time_sum(time) OVER(ORDER BY time ROWS BETWEEN 1
PRECEDING AND 1 FOLLOWING) as time_sum from t";
+ let expected = vec![
+ "+----------------------------+",
+ "| time_sum |",
+ "+----------------------------+",
+ "| 1970-01-01T00:00:00.000005 |",
+ "| 1970-01-01T00:00:00.000009 |",
+ "| 1970-01-01T00:00:00.000012 |",
+ "| 1970-01-01T00:00:00.000014 |",
+ "| 1970-01-01T00:00:00.000010 |",
+ "+----------------------------+",
+ ];
+ assert_batches_eq!(expected, &execute(&ctx, sql).await);
+ // user defined aggregates with window frame should be calling retract
batch
+ assert!(test_state.update_batch());
+ assert!(test_state.retract_batch());
+}
+
+/// Ensure that User defined aggregate used as a window function with a window
+/// frame, but that does not implement retract_batch, does not error
+#[tokio::test]
+async fn test_udaf_as_window_with_frame_without_retract_batch() {
+ let test_state = Arc::new(TestState::new().with_error_on_retract_batch());
+
+ let TestContext { ctx, test_state } =
TestContext::new_with_test_state(test_state);
let sql = "SELECT time_sum(time) OVER(ORDER BY time ROWS BETWEEN 1
PRECEDING AND 1 FOLLOWING) as time_sum from t";
+ // TODO: It is not clear why this is a different value than when retract
batch is used
Review Comment:
> I thought about this some more and have made queries with unbounded
windows without retract_batch error as you suggested in
[999866e](https://github.com/apache/arrow-datafusion/commit/999866e281e454ff8824829fce36ee026140e143)
-- much better to get an error rather than the wrong answer.
>
> It seems to me that there is no fundamental reason DataFusion couldn't
support sliding windows with user defined aggregate functions without
`retract_batch` -- for example it could make a new `Accumulator` instance for
each row and feed in the entire widow.
>
> However, given it is likely to be much more efficient to implement
`retract_batch`, that is what I think we should encourage people to do. If
someone really needs to use a UDAF without `retract_batch` for a sliding
window, we can look into implementing the "full recompute" solution at that time
Agreed. Also, users can define their `UDWF` (User defined window function).
When `UDWF`'s `uses_window_frame` flag is `true`. `evaluate` method of
`PartitionEvaluator` is like "full recompute" approach.
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