From 1e684a1e2ab97129905b2176cfa677d8a3ef828c Mon Sep 17 00:00:00 2001
From: lvlongxiang <lvlongxiang1994@gmail.com>
Date: Fri, 2 Jan 2026 07:19:08 +0000
Subject: [PATCH] perf: optimize HashTableLookupExpr::evaluate by adding
 set_bits_if_exists

---
 .../joins/hash_join/partitioned_hash_eval.rs  | 12 +---
 .../physical-plan/src/joins/join_hash_map.rs  | 58 +++++++++++++++++++
 .../src/joins/stream_join_utils.rs            |  6 +-
 3 files changed, 65 insertions(+), 11 deletions(-)

diff --git a/datafusion/physical-plan/src/joins/hash_join/partitioned_hash_eval.rs b/datafusion/physical-plan/src/joins/hash_join/partitioned_hash_eval.rs
index 4c437e813139d..aafc2acdd1c74 100644
--- a/datafusion/physical-plan/src/joins/hash_join/partitioned_hash_eval.rs
+++ b/datafusion/physical-plan/src/joins/hash_join/partitioned_hash_eval.rs
@@ -343,16 +343,8 @@ impl PhysicalExpr for HashTableLookupExpr {
 
         // Check each hash against the hash table
         let mut buf = MutableBuffer::from_len_zeroed(bit_util::ceil(num_rows, 8));
-        for (idx, hash_value) in hash_array.values().iter().enumerate() {
-            // Use get_matched_indices to check - if it returns any indices, the hash exists
-            let (matched_indices, _) = self
-                .hash_map
-                .get_matched_indices(Box::new(std::iter::once((idx, hash_value))), None);
-
-            if !matched_indices.is_empty() {
-                bit_util::set_bit(buf.as_slice_mut(), idx);
-            }
-        }
+        self.hash_map
+            .set_bits_if_exists(hash_array.values(), buf.as_slice_mut());
 
         Ok(ColumnarValue::Array(Arc::new(
             BooleanArray::new_from_packed(buf, 0, num_rows),
diff --git a/datafusion/physical-plan/src/joins/join_hash_map.rs b/datafusion/physical-plan/src/joins/join_hash_map.rs
index b0ed6dcc7c255..43cd3c052ee12 100644
--- a/datafusion/physical-plan/src/joins/join_hash_map.rs
+++ b/datafusion/physical-plan/src/joins/join_hash_map.rs
@@ -23,6 +23,7 @@ use std::fmt::{self, Debug};
 use std::ops::Sub;
 
 use arrow::datatypes::ArrowNativeType;
+use arrow::util::bit_util;
 use hashbrown::HashTable;
 use hashbrown::hash_table::Entry::{Occupied, Vacant};
 
@@ -124,6 +125,9 @@ pub trait JoinHashMapType: Send + Sync {
         match_indices: &mut Vec<u64>,
     ) -> Option<JoinHashMapOffset>;
 
+    /// Sets bits in the provided buffer if the corresponding hash exists in the map.
+    fn set_bits_if_exists(&self, hash_values: &[u64], buffer: &mut [u8]);
+
     /// Returns `true` if the join hash map contains no entries.
     fn is_empty(&self) -> bool;
 
@@ -196,6 +200,10 @@ impl JoinHashMapType for JoinHashMapU32 {
         )
     }
 
+    fn set_bits_if_exists(&self, hash_values: &[u64], buffer: &mut [u8]) {
+        set_bits_if_exists::<u32>(&self.map, hash_values, buffer);
+    }
+
     fn is_empty(&self) -> bool {
         self.map.is_empty()
     }
@@ -270,6 +278,10 @@ impl JoinHashMapType for JoinHashMapU64 {
         )
     }
 
+    fn set_bits_if_exists(&self, hash_values: &[u64], buffer: &mut [u8]) {
+        set_bits_if_exists::<u64>(&self.map, hash_values, buffer);
+    }
+
     fn is_empty(&self) -> bool {
         self.map.is_empty()
     }
@@ -496,3 +508,49 @@ where
     }
     None
 }
+
+pub fn set_bits_if_exists<T>(
+    map: &HashTable<(u64, T)>,
+    hash_values: &[u64],
+    buffer: &mut [u8],
+) {
+    for (i, &hash) in hash_values.iter().enumerate() {
+        if map.find(hash, |(h, _)| hash == *h).is_some() {
+            bit_util::set_bit(buffer, i);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_set_bits_if_exists() {
+        let mut hash_map = JoinHashMapU32::with_capacity(10);
+        // Build side: insert 10, 20, 30
+        hash_map.update_from_iter(
+            Box::new([10u64, 20u64, 30u64].iter().enumerate()),
+            0,
+        );
+
+        // Probe side: test both existing and non-existing hashes
+        let probe_hashes = vec![10, 11, 20, 21, 30, 31];
+        let mut buffer = vec![0u8; 1];
+        hash_map.set_bits_if_exists(&probe_hashes, &mut buffer);
+
+        for (i, &hash) in probe_hashes.iter().enumerate() {
+            if matches!(hash, 10 | 20 | 30) {
+                assert!(
+                    bit_util::get_bit(&buffer, i),
+                    "Hash {hash} should exist in the map"
+                );
+            } else {
+                assert!(
+                    !bit_util::get_bit(&buffer, i),
+                    "Hash {hash} should NOT exist in the map"
+                );
+            }
+        }
+    }
+}
diff --git a/datafusion/physical-plan/src/joins/stream_join_utils.rs b/datafusion/physical-plan/src/joins/stream_join_utils.rs
index 22cc82a22db5f..39f5f4c0b19f8 100644
--- a/datafusion/physical-plan/src/joins/stream_join_utils.rs
+++ b/datafusion/physical-plan/src/joins/stream_join_utils.rs
@@ -24,7 +24,7 @@ use std::sync::Arc;
 
 use crate::joins::join_hash_map::{
     JoinHashMapOffset, get_matched_indices, get_matched_indices_with_limit_offset,
-    update_from_iter,
+    set_bits_if_exists, update_from_iter,
 };
 use crate::joins::utils::{JoinFilter, JoinHashMapType};
 use crate::metrics::{BaselineMetrics, ExecutionPlanMetricsSet, MetricBuilder};
@@ -94,6 +94,10 @@ impl JoinHashMapType for PruningJoinHashMap {
         )
     }
 
+    fn set_bits_if_exists(&self, hash_values: &[u64], buffer: &mut [u8]) {
+        set_bits_if_exists::<u64>(&self.map, hash_values, buffer);
+    }
+
     fn is_empty(&self) -> bool {
         self.map.is_empty()
     }