Skip to content

fix: preserve global limit for multi-partition fetch #23800

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
discord9 wants to merge 1 commit into
base: main
Choose a base branch
from
+364 −52
Draft

fix: preserve global limit for multi-partition fetch #23800

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
246 changes: 226 additions & 20 deletions datafusion/core/tests/physical_optimizer/limit_pushdown.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,8 @@
use std::sync::Arc;

use crate::physical_optimizer::test_utils::{
coalesce_partitions_exec, global_limit_exec, hash_join_exec, local_limit_exec,
sort_exec, sort_preserving_merge_exec, stream_exec,
TestScan, coalesce_partitions_exec, global_limit_exec, hash_join_exec,
local_limit_exec, sort_exec, sort_preserving_merge_exec, stream_exec,
};

use arrow::compute::SortOptions;
Expand All @@ -38,6 +38,7 @@ use datafusion_physical_plan::filter::FilterExec;
use datafusion_physical_plan::joins::NestedLoopJoinExec;
use datafusion_physical_plan::projection::ProjectionExec;
use datafusion_physical_plan::repartition::RepartitionExec;
use datafusion_physical_plan::union::UnionExec;
use datafusion_physical_plan::{ExecutionPlan, get_plan_string};

fn create_schema() -> SchemaRef {
Expand Down Expand Up @@ -162,6 +163,208 @@ fn transforms_streaming_table_exec_into_fetching_version_and_keeps_the_global_li
Ok(())
}

#[test]
fn keeps_global_limit_above_fetch_capable_multi_partition_scan() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(
TestScan::new(schema, vec![])
.with_supports_fetch(true)
.with_partition_count(2),
);
let global_limit = global_limit_exec(scan, 0, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
CoalescePartitionsExec: fetch=5
TestScan: fetch=5
"
);

Ok(())
}

#[test]
fn keeps_global_offset_limit_above_fetch_capable_multi_partition_scan() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(
TestScan::new(schema, vec![])
.with_supports_fetch(true)
.with_partition_count(2),
);
let global_limit = global_limit_exec(scan, 2, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
GlobalLimitExec: skip=2, fetch=5
CoalescePartitionsExec: fetch=7
TestScan: fetch=7
"
);

Ok(())
}

#[test]
fn preserves_existing_per_partition_fetch_under_global_limit() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(
TestScan::new(schema, vec![])
.with_supports_fetch(true)
.with_partition_count(2),
);
let scan = scan.with_fetch(Some(3)).unwrap();
let global_limit = global_limit_exec(scan, 0, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
CoalescePartitionsExec: fetch=5
TestScan: fetch=3
"
);

Ok(())
}

#[test]
fn adds_global_boundary_above_unfetchable_multi_partition_scan() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(TestScan::new(schema, vec![]).with_partition_count(2));
let global_limit = global_limit_exec(scan, 0, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
CoalescePartitionsExec: fetch=5
TestScan
"
);

Ok(())
}

#[test]
fn materializes_global_boundary_before_pushing_into_union_children() -> Result<()> {
let schema = create_schema();
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let union = UnionExec::try_new(vec![left, right])?;
let global_limit = global_limit_exec(union, 0, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
CoalescePartitionsExec: fetch=5
UnionExec
TestScan: fetch=5
TestScan: fetch=5
"
);

Ok(())
}

#[test]
fn materializes_global_boundary_for_offset_only_multi_partition_scan() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(TestScan::new(schema, vec![]).with_partition_count(2));
let global_limit = global_limit_exec(scan, 2, None);

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
GlobalLimitExec: skip=2, fetch=None
CoalescePartitionsExec
TestScan
"
);

Ok(())
}

#[test]
fn removes_noop_global_limit_without_materializing_boundary() -> Result<()> {
let schema = create_schema();
let scan = Arc::new(TestScan::new(schema, vec![]));
let noop_global_limit = global_limit_exec(scan, 0, None);

let optimized =
LimitPushdown::new().optimize(noop_global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@"TestScan"
);

Ok(())
}

#[test]
fn keeps_global_limit_above_local_limit_on_multi_partition_union() -> Result<()> {
let schema = create_schema();
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let union = UnionExec::try_new(vec![left, right])?;
let local_limit = local_limit_exec(union, 3);
let global_limit = global_limit_exec(local_limit, 0, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
CoalescePartitionsExec: fetch=5
UnionExec
TestScan: fetch=3
TestScan: fetch=3
"
);

Ok(())
}

#[test]
fn keeps_global_offset_limit_above_local_limit_on_multi_partition_union() -> Result<()> {
let schema = create_schema();
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let union = UnionExec::try_new(vec![left, right])?;
let local_limit = local_limit_exec(union, 3);
let global_limit = global_limit_exec(local_limit, 2, Some(5));

let optimized = LimitPushdown::new().optimize(global_limit, &ConfigOptions::new())?;

insta::assert_snapshot!(
format_plan(&optimized),
@r"
GlobalLimitExec: skip=2, fetch=5
CoalescePartitionsExec: fetch=7
UnionExec
TestScan: fetch=3
TestScan: fetch=3
"
);

Ok(())
}

fn join_on_columns(
left_col: &str,
right_col: &str,
Expand All @@ -180,8 +383,9 @@ fn join_on_columns(
fn absorbs_limit_into_hash_join_inner() -> Result<()> {
// HashJoinExec with Inner join should absorb limit via with_fetch
let schema = create_schema();
let left = empty_exec(Arc::clone(&schema));
let right = empty_exec(Arc::clone(&schema));
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let on = join_on_columns("c1", "c1");
let hash_join = hash_join_exec(left, right, on, None, &JoinType::Inner)?;
let global_limit = global_limit_exec(hash_join, 0, Some(5));
Expand All @@ -192,8 +396,8 @@ fn absorbs_limit_into_hash_join_inner() -> Result<()> {
@r"
GlobalLimitExec: skip=0, fetch=5
HashJoinExec: mode=Partitioned, join_type=Inner, on=[(c1@0, c1@0)]
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand All @@ -205,8 +409,8 @@ fn absorbs_limit_into_hash_join_inner() -> Result<()> {
optimized,
@r"
HashJoinExec: mode=Partitioned, join_type=Inner, on=[(c1@0, c1@0)], fetch=5
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand All @@ -217,8 +421,9 @@ fn absorbs_limit_into_hash_join_inner() -> Result<()> {
fn absorbs_limit_into_hash_join_right() -> Result<()> {
// HashJoinExec with Right join should absorb limit via with_fetch
let schema = create_schema();
let left = empty_exec(Arc::clone(&schema));
let right = empty_exec(Arc::clone(&schema));
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let on = join_on_columns("c1", "c1");
let hash_join = hash_join_exec(left, right, on, None, &JoinType::Right)?;
let global_limit = global_limit_exec(hash_join, 0, Some(10));
Expand All @@ -229,8 +434,8 @@ fn absorbs_limit_into_hash_join_right() -> Result<()> {
@r"
GlobalLimitExec: skip=0, fetch=10
HashJoinExec: mode=Partitioned, join_type=Right, on=[(c1@0, c1@0)]
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand All @@ -242,8 +447,8 @@ fn absorbs_limit_into_hash_join_right() -> Result<()> {
optimized,
@r"
HashJoinExec: mode=Partitioned, join_type=Right, on=[(c1@0, c1@0)], fetch=10
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand All @@ -254,8 +459,9 @@ fn absorbs_limit_into_hash_join_right() -> Result<()> {
fn absorbs_limit_into_hash_join_left() -> Result<()> {
// during probing, then unmatched rows at the end, stopping when limit is reached
let schema = create_schema();
let left = empty_exec(Arc::clone(&schema));
let right = empty_exec(Arc::clone(&schema));
let left =
Arc::new(TestScan::new(Arc::clone(&schema), vec![]).with_supports_fetch(true));
let right = Arc::new(TestScan::new(schema, vec![]).with_supports_fetch(true));
let on = join_on_columns("c1", "c1");
let hash_join = hash_join_exec(left, right, on, None, &JoinType::Left)?;
let global_limit = global_limit_exec(hash_join, 0, Some(5));
Expand All @@ -266,8 +472,8 @@ fn absorbs_limit_into_hash_join_left() -> Result<()> {
@r"
GlobalLimitExec: skip=0, fetch=5
HashJoinExec: mode=Partitioned, join_type=Left, on=[(c1@0, c1@0)]
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand All @@ -279,8 +485,8 @@ fn absorbs_limit_into_hash_join_left() -> Result<()> {
optimized,
@r"
HashJoinExec: mode=Partitioned, join_type=Left, on=[(c1@0, c1@0)], fetch=5
EmptyExec
EmptyExec
TestScan
TestScan
"
);

Expand Down
Loading
Loading