Avoid generate duplicate sort Keys from Window Expressions, fix bug when decide Window Expressions ordering

datafusion/core/src/physical_plan/planner.rs

@@ -564,12 +564,12 @@ impl DefaultPhysicalPlanner {
                         }
                         _ => unreachable!(),
                     };
-                    let sort_keys = get_sort_keys(&window_expr[0]);
+                    let sort_keys = get_sort_keys(&window_expr[0])?;
                     if window_expr.len() > 1 {
                         debug_assert!(
                             window_expr[1..]
                                 .iter()
-                                .all(|expr| get_sort_keys(expr) == sort_keys),
+                                .all(|expr| get_sort_keys(expr).unwrap() == sort_keys),
                             "all window expressions shall have the same sort keys, as guaranteed by logical planning"
                         );
                     }

datafusion/core/tests/sql/select.rs

@@ -835,6 +835,88 @@ async fn query_on_string_dictionary() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn sort_on_window_null_string() -> Result<()> {
+    let d1: DictionaryArray<Int32Type> =
+        vec![Some("one"), None, Some("three")].into_iter().collect();
+    let d2: StringArray = vec![Some("ONE"), None, Some("THREE")].into_iter().collect();
+    let d3: LargeStringArray =
+        vec![Some("One"), None, Some("Three")].into_iter().collect();
+
+    let batch = RecordBatch::try_from_iter(vec![
+        ("d1", Arc::new(d1) as ArrayRef),
+        ("d2", Arc::new(d2) as ArrayRef),
+        ("d3", Arc::new(d3) as ArrayRef),
+    ])
+    .unwrap();
+
+    let ctx = SessionContext::with_config(SessionConfig::new().with_target_partitions(2));
+    ctx.register_batch("test", batch)?;
+
+    let sql =
+        "SELECT d1, row_number() OVER (partition by d1) as rn1 FROM test order by d1 asc";
+
+    let actual = execute_to_batches(&ctx, sql).await;
+    // NULLS LAST
+    let expected = vec![
+        "+-------+-----+",
+        "| d1    | rn1 |",
+        "+-------+-----+",
+        "| one   | 1   |",
+        "| three | 1   |",
+        "|       | 1   |",
+        "+-------+-----+",
+    ];
+    assert_batches_eq!(expected, &actual);
+
+    let sql = "SELECT d2, row_number() OVER (partition by d2) as rn1 FROM test";
+    let actual = execute_to_batches(&ctx, sql).await;
+    // NULLS LAST
+    let expected = vec![
+        "+-------+-----+",
+        "| d2    | rn1 |",
+        "+-------+-----+",
+        "| ONE   | 1   |",
+        "| THREE | 1   |",
+        "|       | 1   |",
+        "+-------+-----+",
+    ];
+    assert_batches_eq!(expected, &actual);
+
+    let sql =
+        "SELECT d2, row_number() OVER (partition by d2 order by d2 desc) as rn1 FROM test";
+
+    let actual = execute_to_batches(&ctx, sql).await;
+    // NULLS FIRST
+    let expected = vec![
+        "+-------+-----+",
+        "| d2    | rn1 |",
+        "+-------+-----+",
+        "|       | 1   |",
+        "| THREE | 1   |",
+        "| ONE   | 1   |",
+        "+-------+-----+",
+    ];
+    assert_batches_eq!(expected, &actual);
+
+    // FIXME sort on LargeUtf8 String has bug.
+    // let sql =
+    //     "SELECT d3, row_number() OVER (partition by d3) as rn1 FROM test";
+    // let actual = execute_to_batches(&ctx, sql).await;
+    // let expected = vec![
+    //     "+-------+-----+",
+    //     "| d3    | rn1 |",
+    //     "+-------+-----+",
+    //     "|       | 1   |",
+    //     "| One   | 1   |",
+    //     "| Three | 1   |",
+    //     "+-------+-----+",
+    // ];
+    // assert_batches_eq!(expected, &actual);
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn filter_with_time32second() -> Result<()> {
     let ctx = SessionContext::new();

datafusion/core/tests/sql/window.rs

@@ -1642,7 +1642,120 @@ async fn test_window_agg_sort() -> Result<()> {
     assert_eq!(
         expected, actual_trim_last,
         "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
-        expected, actual
+        expected, actual_trim_last
+    );
+    Ok(())
+}
+
+#[tokio::test]
+async fn over_order_by_sort_keys_sorting_prefix_compacting() -> Result<()> {
+    let ctx = SessionContext::with_config(SessionConfig::new().with_target_partitions(2));
+    register_aggregate_csv(&ctx).await?;
+
+    let sql = "SELECT c2, MAX(c9) OVER (ORDER BY c2), SUM(c9) OVER (), MIN(c9) OVER (ORDER BY c2, c9) from aggregate_test_100";
+
+    let msg = format!("Creating logical plan for '{}'", sql);
+    let plan = ctx.create_logical_plan(sql).expect(&msg);
+    let state = ctx.state();
+    let logical_plan = state.optimize(&plan)?;
+    let physical_plan = state.create_physical_plan(&logical_plan).await?;
+    let formatted = displayable(physical_plan.as_ref()).indent().to_string();
+    // Only 1 SortExec was added
+    let expected = {
+        vec![
+            "ProjectionExec: expr=[c2@3 as c2, MAX(aggregate_test_100.c9) ORDER BY [aggregate_test_100.c2 ASC NULLS LAST] RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW@1 as MAX(aggregate_test_100.c9), SUM(aggregate_test_100.c9) ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING@0 as SUM(aggregate_test_100.c9), MIN(aggregate_test_100.c9) ORDER BY [aggregate_test_100.c2 ASC NULLS LAST, aggregate_test_100.c9 ASC NULLS LAST] RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW@2 as MIN(aggregate_test_100.c9)]",
+            "  WindowAggExec: wdw=[SUM(aggregate_test_100.c9): Ok(Field { name: \"SUM(aggregate_test_100.c9)\", data_type: UInt64, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Rows, start_bound: Preceding(UInt64(NULL)), end_bound: Following(UInt64(NULL)) }]",
+            "    WindowAggExec: wdw=[MAX(aggregate_test_100.c9): Ok(Field { name: \"MAX(aggregate_test_100.c9)\", data_type: UInt32, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Range, start_bound: Preceding(UInt32(NULL)), end_bound: CurrentRow }]",
+            "      WindowAggExec: wdw=[MIN(aggregate_test_100.c9): Ok(Field { name: \"MIN(aggregate_test_100.c9)\", data_type: UInt32, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Range, start_bound: Preceding(UInt32(NULL)), end_bound: CurrentRow }]",
+            "        SortExec: [c2@0 ASC NULLS LAST,c9@1 ASC NULLS LAST]"
+        ]
+    };
+
+    let actual: Vec<&str> = formatted.trim().lines().collect();
+    let actual_len = actual.len();
+    let actual_trim_last = &actual[..actual_len - 1];
+    assert_eq!(
+        expected, actual_trim_last,
+        "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
+        expected, actual_trim_last
+    );
+    Ok(())
+}
+
+/// FIXME: for now we are not detecting prefix of sorting keys in order to re-arrange with global and save one SortExec
+#[tokio::test]
+async fn over_order_by_sort_keys_sorting_global_order_compacting() -> Result<()> {
+    let ctx = SessionContext::with_config(SessionConfig::new().with_target_partitions(2));
+    register_aggregate_csv(&ctx).await?;
+
+    let sql = "SELECT c2, MAX(c9) OVER (ORDER BY c9, c2), SUM(c9) OVER (), MIN(c9) OVER (ORDER BY c2, c9) from aggregate_test_100 ORDER BY c2";
+    let msg = format!("Creating logical plan for '{}'", sql);
+    let plan = ctx.create_logical_plan(sql).expect(&msg);
+    let state = ctx.state();
+    let logical_plan = state.optimize(&plan)?;
+    let physical_plan = state.create_physical_plan(&logical_plan).await?;
+    let formatted = displayable(physical_plan.as_ref()).indent().to_string();
+    // 3 SortExec are added
+    let expected = {
+        vec![
+            "SortExec: [c2@0 ASC NULLS LAST]",
+            "  CoalescePartitionsExec",
+            "    ProjectionExec: expr=[c2@3 as c2, MAX(aggregate_test_100.c9) ORDER BY [aggregate_test_100.c9 ASC NULLS LAST, aggregate_test_100.c2 ASC NULLS LAST] RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW@1 as MAX(aggregate_test_100.c9), SUM(aggregate_test_100.c9) ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING@0 as SUM(aggregate_test_100.c9), MIN(aggregate_test_100.c9) ORDER BY [aggregate_test_100.c2 ASC NULLS LAST, aggregate_test_100.c9 ASC NULLS LAST] RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW@2 as MIN(aggregate_test_100.c9)]",
+            "      RepartitionExec: partitioning=RoundRobinBatch(2)",
+            "        WindowAggExec: wdw=[SUM(aggregate_test_100.c9): Ok(Field { name: \"SUM(aggregate_test_100.c9)\", data_type: UInt64, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Rows, start_bound: Preceding(UInt64(NULL)), end_bound: Following(UInt64(NULL)) }]",
+            "          WindowAggExec: wdw=[MAX(aggregate_test_100.c9): Ok(Field { name: \"MAX(aggregate_test_100.c9)\", data_type: UInt32, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Range, start_bound: Preceding(UInt32(NULL)), end_bound: CurrentRow }]",
+            "            SortExec: [c9@2 ASC NULLS LAST,c2@1 ASC NULLS LAST]",
+            "              WindowAggExec: wdw=[MIN(aggregate_test_100.c9): Ok(Field { name: \"MIN(aggregate_test_100.c9)\", data_type: UInt32, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Range, start_bound: Preceding(UInt32(NULL)), end_bound: CurrentRow }]",
+            "                SortExec: [c2@0 ASC NULLS LAST,c9@1 ASC NULLS LAST]",
+        ]
+    };
+
+    let actual: Vec<&str> = formatted.trim().lines().collect();
+    let actual_len = actual.len();
+    let actual_trim_last = &actual[..actual_len - 1];
+    assert_eq!(
+        expected, actual_trim_last,
+        "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
+        expected, actual_trim_last
+    );
+    Ok(())
+}
+
+#[tokio::test]
+async fn test_window_partition_by_order_by() -> Result<()> {
+    let ctx = SessionContext::with_config(SessionConfig::new().with_target_partitions(2));
+    register_aggregate_csv(&ctx).await?;
+
+    let sql = "SELECT \
+               SUM(c4) OVER(PARTITION BY c1, c2 ORDER BY c2 ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING),\
+               COUNT(*) OVER(PARTITION BY c1 ORDER BY c2 ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) \
+               FROM aggregate_test_100";
+
+    let msg = format!("Creating logical plan for '{}'", sql);
+    let plan = ctx.create_logical_plan(sql).expect(&msg);
+    let state = ctx.state();
+    let logical_plan = state.optimize(&plan)?;
+    let physical_plan = state.create_physical_plan(&logical_plan).await?;
+    let formatted = displayable(physical_plan.as_ref()).indent().to_string();
+    // Only 1 SortExec was added
+    let expected = {
+        vec![
+            "ProjectionExec: expr=[SUM(aggregate_test_100.c4) PARTITION BY [aggregate_test_100.c1, aggregate_test_100.c2] ORDER BY [aggregate_test_100.c2 ASC NULLS LAST] ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING@0 as SUM(aggregate_test_100.c4), COUNT(UInt8(1)) PARTITION BY [aggregate_test_100.c1] ORDER BY [aggregate_test_100.c2 ASC NULLS LAST] ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING@1 as COUNT(UInt8(1))]",
+            "  WindowAggExec: wdw=[SUM(aggregate_test_100.c4): Ok(Field { name: \"SUM(aggregate_test_100.c4)\", data_type: Int64, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Rows, start_bound: Preceding(UInt64(1)), end_bound: Following(UInt64(1)) }, COUNT(UInt8(1)): Ok(Field { name: \"COUNT(UInt8(1))\", data_type: Int64, nullable: true, dict_id: 0, dict_is_ordered: false, metadata: {} }), frame: WindowFrame { units: Rows, start_bound: Preceding(UInt64(1)), end_bound: Following(UInt64(1)) }]",
+            "    SortExec: [c1@0 ASC NULLS LAST,c2@1 ASC NULLS LAST]",
+            "      CoalesceBatchesExec: target_batch_size=4096",
+            "        RepartitionExec: partitioning=Hash([Column { name: \"c1\", index: 0 }], 2)",
+            "          RepartitionExec: partitioning=RoundRobinBatch(2)",
+        ]
+    };
+
+    let actual: Vec<&str> = formatted.trim().lines().collect();
+    let actual_len = actual.len();
+    let actual_trim_last = &actual[..actual_len - 1];
+    assert_eq!(
+        expected, actual_trim_last,
+        "\n\nexpected:\n\n{:#?}\nactual:\n\n{:#?}\n\n",
+        expected, actual_trim_last
     );
     Ok(())
 }

datafusion/expr/src/logical_plan/builder.rs

@@ -22,7 +22,7 @@ use crate::expr_rewriter::{
     normalize_cols, rewrite_sort_cols_by_aggs,
 };
 use crate::type_coercion::binary::comparison_coercion;
-use crate::utils::{columnize_expr, exprlist_to_fields, from_plan};
+use crate::utils::{columnize_expr, compare_sort_expr, exprlist_to_fields, from_plan};
 use crate::{and, binary_expr, Operator};
 use crate::{
     logical_plan::{
@@ -43,6 +43,7 @@ use datafusion_common::{
     ToDFSchema,
 };
 use std::any::Any;
+use std::cmp::Ordering;
 use std::collections::{HashMap, HashSet};
 use std::convert::TryFrom;
 use std::sync::Arc;
@@ -250,16 +251,29 @@ impl LogicalPlanBuilder {
     ) -> Result<LogicalPlan> {
         let mut plan = input;
         let mut groups = group_window_expr_by_sort_keys(&window_exprs)?;
-        // sort by sort_key len descending, so that more deeply sorted plans gets nested further
-        // down as children; to further mimic the behavior of PostgreSQL, we want stable sort
-        // and a reverse so that tieing sort keys are reversed in order; note that by this rule
-        // if there's an empty over, it'll be at the top level
-        groups.sort_by(|(key_a, _), (key_b, _)| key_a.len().cmp(&key_b.len()));
-        groups.reverse();
+        // To align with the behavior of PostgreSQL, we want the sort_keys sorted as same rule as PostgreSQL that first
+        // we compare the sort key themselves and if one window's sort keys are a prefix of another
+        // put the window with more sort keys first. so more deeply sorted plans gets nested further down as children.
+        // The sort_by() implementation here is a stable sort.
+        // Note that by this rule if there's an empty over, it'll be at the top level
+        groups.sort_by(|(key_a, _), (key_b, _)| {
+            for (first, second) in key_a.iter().zip(key_b.iter()) {
+                let key_ordering = compare_sort_expr(first, second, plan.schema());
+                match key_ordering {
+                    Ordering::Less => {
+                        return Ordering::Less;
+                    }
+                    Ordering::Greater => {
+                        return Ordering::Greater;
+                    }
+                    Ordering::Equal => {}
+                }
+            }
+            key_b.len().cmp(&key_a.len())
+        });
         for (_, exprs) in groups {
             let window_exprs = exprs.into_iter().cloned().collect::<Vec<_>>();
-            // the partition and sort itself is done at physical level, see physical_planner's
-            // fn create_initial_plan
+            // the partition and sort itself is done at physical level, see the BasicEnforcement rule
             plan = LogicalPlanBuilder::from(plan)
                 .window(window_exprs)?
                 .build()?;