alamb commented on code in PR #6592:
URL: https://github.com/apache/arrow-datafusion/pull/6592#discussion_r1223130985
##########
datafusion/physical-expr/src/window/partition_evaluator.rs:
##########
@@ -25,24 +25,70 @@ use datafusion_common::{DataFusionError, ScalarValue};
use std::fmt::Debug;
use std::ops::Range;
-/// Partition evaluator
+/// Partition evaluator for Window Functions
+///
+/// An implementation of this trait is created and used for each
+/// partition defined by the OVER clause.
+///
+/// For example, evaluating `window_func(val) OVER (PARTITION BY col)`
+/// on the following data:
+///
+/// ```text
+/// col | val
+/// --- + ----
+/// A | 1
+/// A | 1
+/// C | 2
+/// D | 3
+/// D | 3
+/// ```
+///
+/// Will instantiate three `PartitionEvaluator`s, one each for the
+/// partitions defined by `col=A`, `col=B`, and `col=C`.
+///
+/// There are two types of `PartitionEvaluator`:
+///
+/// # Stateless `PartitionEvaluator`
+///
Review Comment:
Thank you @mustafasrepo -- this is super helpful. I am incorporating this
information into this PR
--
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]
