gene-bordegaray commented on code in PR #22207:
URL: https://github.com/apache/datafusion/pull/22207#discussion_r3261586069
##########
datafusion/physical-expr/src/partitioning.rs:
##########
@@ -133,13 +136,225 @@ impl Display for Partitioning {
.join(", ");
write!(f, "Hash([{phy_exprs_str}], {size})")
}
+ Partitioning::Range(range) => write!(f, "{range}"),
Partitioning::UnknownPartitioning(size) => {
write!(f, "UnknownPartitioning({size})")
}
}
}
}
+/// Physical range partitioning.
+///
+/// [`RangePartitioning`] describes range bounds over one or more physical
+/// expressions. Each [`RangePartition`] represents one output partition and
must
+/// contain exactly one [`RangeInterval`] for each partition expression.
+///
+/// The source declaring this partitioning is responsible for ensuring that,
for
+/// every emitted row, the row belongs to exactly one partition and is emitted
by
+/// that partition. The declared ranges do not need to cover values that the
plan
+/// cannot emit.
+///
+/// Each lower and upper bound explicitly records whether it is inclusive.
+/// Unbounded sides are represented with `None`, bound values should be
non-null
+/// until null routing semantics are defined.
+///
+/// For example, a scan can declare date and city range partitions as:
+///
+/// ```text
+/// exprs = [date, city]
+///
+/// partition 0:
+/// date in [2021-01-01, 2022-01-01)
+/// city in [Allston, Boston)
+///
+/// partition 1:
+/// date in [2021-01-01, 2022-01-01)
+/// city in [Boston, NYC)
+/// ```
+///
+/// NOTE: Optimizer and execution behavior for this partitioning is
intentionally
+/// not implemented and will be introduced incrementally. This public API keeps
+/// the partition ranges explicit for users. Repartitioning may compile the
same
+/// metadata into a more efficient internal router.
+#[derive(Debug, Clone)]
+pub struct RangePartitioning {
+ partition_exprs: Vec<Arc<dyn PhysicalExpr>>,
+ partitions: Vec<RangePartition>,
+}
+
+impl RangePartitioning {
+ /// Creates range partitioning metadata.
+ ///
+ /// The caller is responsible for ensuring each partition has one range per
+ /// partition expression and for satisfying the contract documented on
+ /// [`RangePartitioning`].
+ pub fn new(
+ partition_exprs: Vec<Arc<dyn PhysicalExpr>>,
+ partitions: Vec<RangePartition>,
+ ) -> Self {
+ Self {
+ partition_exprs,
+ partitions,
+ }
+ }
+
+ /// Returns the partition expressions.
+ pub fn partition_exprs(&self) -> &[Arc<dyn PhysicalExpr>] {
+ &self.partition_exprs
+ }
+
+ /// Returns the declared range partitions.
+ pub fn partitions(&self) -> &[RangePartition] {
+ &self.partitions
+ }
+
+ /// Returns the number of partitions.
+ pub fn partition_count(&self) -> usize {
+ self.partitions.len()
+ }
+
+ fn project(
+ &self,
+ mapping: &ProjectionMapping,
+ input_eq_properties: &EquivalenceProperties,
+ ) -> Option<Self> {
+ let partition_exprs = input_eq_properties
+ .project_expressions(&self.partition_exprs, mapping)
+ .collect::<Option<Vec<_>>>()?;
+
+ Some(Self {
+ partition_exprs,
+ partitions: self.partitions.clone(),
+ })
+ }
+}
+
+impl Display for RangePartitioning {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ let partitions = self
+ .partitions
+ .iter()
+ .map(|partition| format!("{partition}"))
+ .collect::<Vec<_>>()
+ .join(", ");
+ write!(
+ f,
+ "Range({}, [{}], {})",
+ format_physical_expr_list(&self.partition_exprs),
+ partitions,
+ self.partition_count()
+ )
+ }
+}
+
+impl PartialEq for RangePartitioning {
+ fn eq(&self, other: &Self) -> bool {
+ physical_exprs_equal(&self.partition_exprs, &other.partition_exprs)
+ && self.partitions == other.partitions
+ }
+}
+
+/// Ranges for one output partition in a [`RangePartitioning`].
+#[derive(Debug, Clone, PartialEq)]
+pub struct RangePartition {
+ ranges: Vec<RangeInterval>,
+}
+
+impl RangePartition {
+ /// Creates a partition from one range per partition expression.
+ pub fn new(ranges: Vec<RangeInterval>) -> Self {
+ Self { ranges }
+ }
+
+ /// Returns the ranges for this partition.
+ pub fn ranges(&self) -> &[RangeInterval] {
+ &self.ranges
+ }
+}
+
+impl Display for RangePartition {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ let ranges = self
+ .ranges
+ .iter()
+ .map(|range| format!("{range}"))
+ .collect::<Vec<_>>()
+ .join(", ");
+ write!(f, "({ranges})")
+ }
+}
+
+/// A scalar interval in one range partition dimension.
+#[derive(Debug, Clone, PartialEq)]
+pub struct RangeInterval {
+ lower: Option<RangeBound>,
+ upper: Option<RangeBound>,
Review Comment:
The reason I leaned toward this was readability. I think we could make the
documentation clear or even provide helpers to abstract this nicely so I am not
concerned with this.
I am ok with dong split points as well as long as other maintainers think
this is ok for public API 👍
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