mingmwang commented on code in PR #6084:
URL: https://github.com/apache/arrow-datafusion/pull/6084#discussion_r1177296225
##########
datafusion/expr/src/logical_plan/plan.rs:
##########
@@ -484,6 +484,97 @@ impl LogicalPlan {
_ => Ok(self),
}
}
+
+ /// Returns the maximum number of rows that this plan can output.
+ pub fn max_rows(self: &LogicalPlan) -> Option<usize> {
+ match self {
+ LogicalPlan::Projection(Projection { input, .. }) =>
input.max_rows(),
+ LogicalPlan::Filter(Filter { input, .. }) => input.max_rows(),
+ LogicalPlan::Window(Window { input, .. }) => input.max_rows(),
+ LogicalPlan::Aggregate(Aggregate {
+ input, group_expr, ..
+ }) => {
+ if group_expr.is_empty() {
+ Some(1)
+ } else {
+ input.max_rows()
+ }
+ }
+ LogicalPlan::Sort(Sort { input, fetch, .. }) => {
+ match (fetch, input.max_rows()) {
+ (Some(fetch_limit), Some(input_max)) => {
+ Some(input_max.min(*fetch_limit))
+ }
+ (Some(fetch_limit), None) => Some(*fetch_limit),
+ (None, Some(input_max)) => Some(input_max),
+ (None, None) => None,
+ }
+ }
+ LogicalPlan::Join(Join {
+ left,
+ right,
+ join_type,
+ ..
+ }) => match join_type {
+ JoinType::Inner | JoinType::Left | JoinType::Right |
JoinType::Full => {
+ match (left.max_rows(), right.max_rows()) {
+ (Some(left_max), Some(right_max)) => {
+ let min_rows = match join_type {
+ JoinType::Left => left_max,
+ JoinType::Right => right_max,
+ JoinType::Full => left_max + right_max,
+ _ => 0,
+ };
+ Some((left_max * right_max).max(min_rows))
+ }
+ _ => None,
+ }
+ }
+ JoinType::LeftSemi | JoinType::LeftAnti => left.max_rows(),
+ JoinType::RightSemi | JoinType::RightAnti => right.max_rows(),
+ },
+ LogicalPlan::CrossJoin(CrossJoin { left, right, .. }) => {
+ match (left.max_rows(), right.max_rows()) {
+ (Some(left_max), Some(right_max)) => Some(left_max *
right_max),
+ _ => None,
+ }
+ }
+ LogicalPlan::Repartition(Repartition { input, .. }) =>
input.max_rows(),
+ LogicalPlan::Union(Union { inputs, .. }) => inputs
+ .iter()
+ .map(|plan| plan.max_rows())
+ .try_fold(0usize, |mut acc, input_max| {
+ if let Some(i_max) = input_max {
+ acc += i_max;
+ Some(acc)
+ } else {
+ None
+ }
+ }),
+ LogicalPlan::TableScan(TableScan { fetch, .. }) => *fetch,
+ LogicalPlan::EmptyRelation(_) => Some(0),
+ LogicalPlan::Subquery(_) => None,
+ LogicalPlan::SubqueryAlias(SubqueryAlias { input, .. }) =>
input.max_rows(),
+ LogicalPlan::Limit(Limit { fetch, .. }) => *fetch,
+ LogicalPlan::Distinct(Distinct { input }) => input.max_rows(),
+ LogicalPlan::Unnest(_) => None,
+ LogicalPlan::CreateMemoryTable(_)
+ | LogicalPlan::CreateExternalTable(_)
+ | LogicalPlan::CreateView(_)
+ | LogicalPlan::CreateCatalogSchema(_)
+ | LogicalPlan::CreateCatalog(_)
+ | LogicalPlan::DropTable(_)
+ | LogicalPlan::DropView(_)
+ | LogicalPlan::Explain(_)
+ | LogicalPlan::Analyze(_)
+ | LogicalPlan::Dml(_)
+ | LogicalPlan::DescribeTable(_)
+ | LogicalPlan::Prepare(_)
+ | LogicalPlan::Statement(_)
+ | LogicalPlan::Values(_)
Review Comment:
Will add.
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