feat(streaming): reduce join cache entry size

src/stream/Cargo.toml

@@ -19,6 +19,7 @@ anyhow = "1"
 async-recursion = "1"
 async-stream = "0.3"
 async-trait = "0.1"
+auto_enums = "0.8"
 await-tree = { workspace = true }
 bytes = "1"
 educe = "0.4"

src/stream/src/executor/managed_state/join/join_entry_state.rs

@@ -12,21 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::collections::{btree_map, BTreeMap};
-
 use risingwave_common::estimate_size::KvSize;
 
 use super::*;
 
-#[expect(dead_code)]
-type JoinEntryStateIter<'a> = btree_map::Iter<'a, PkType, StateValueType>;
-
-#[expect(dead_code)]
-type JoinEntryStateValues<'a> = btree_map::Values<'a, PkType, StateValueType>;
-
-#[expect(dead_code)]
-type JoinEntryStateValuesMut<'a> = btree_map::ValuesMut<'a, PkType, StateValueType>;
-
 /// We manages a `HashMap` in memory for all entries belonging to a join key.
 /// When evicted, `cached` does not hold any entries.
 ///
@@ -35,7 +24,7 @@ type JoinEntryStateValuesMut<'a> = btree_map::ValuesMut<'a, PkType, StateValueTy
 #[derive(Default)]
 pub struct JoinEntryState {
     /// The full copy of the state.
-    cached: BTreeMap<PkType, StateValueType>,
+    cached: join_row_set::JoinRowSet<PkType, StateValueType>,
     kv_heap_size: KvSize,
 }
 
@@ -97,20 +86,11 @@ mod tests {
 
     use super::*;
 
-    #[tokio::test]
-    async fn test_managed_all_or_none_state() {
-        let mut managed_state = JoinEntryState::default();
-        let pk_indices = [0];
-        let col1 = [1, 2, 3];
-        let col2 = [6, 5, 4];
-        let col_types = vec![DataType::Int64, DataType::Int64];
-        let data_chunk = DataChunk::from_pretty(
-            "I I
-             3 4
-             2 5
-             1 6",
-        );
-
+    fn insert_chunk(
+        managed_state: &mut JoinEntryState,
+        pk_indices: &[usize],
+        data_chunk: &DataChunk,
+    ) {
         for row_ref in data_chunk.rows() {
             let row: OwnedRow = row_ref.into_owned_row();
             let value_indices = (0..row.len() - 1).collect_vec();
@@ -120,9 +100,16 @@ mod tests {
             let join_row = JoinRow { row, degree: 0 };
             managed_state.insert(pk, join_row.encode());
         }
+    }
 
+    fn check(
+        managed_state: &mut JoinEntryState,
+        col_types: &[DataType],
+        col1: &[i64],
+        col2: &[i64],
+    ) {
         for ((_, matched_row), (d1, d2)) in managed_state
-            .values_mut(&col_types)
+            .values_mut(col_types)
             .zip_eq_debug(col1.iter().zip_eq_debug(col2.iter()))
         {
             let matched_row = matched_row.unwrap();
@@ -131,4 +118,35 @@ mod tests {
             assert_eq!(matched_row.degree, 0);
         }
     }
+
+    #[tokio::test]
+    async fn test_managed_all_or_none_state() {
+        let mut managed_state = JoinEntryState::default();
+        let col_types = vec![DataType::Int64, DataType::Int64];
+        let pk_indices = [0];
+
+        let col1 = [3, 2, 1];
+        let col2 = [4, 5, 6];
+        let data_chunk1 = DataChunk::from_pretty(
+            "I I
+             3 4
+             2 5
+             1 6",
+        );
+
+        // `Vec` in state
+        insert_chunk(&mut managed_state, &pk_indices, &data_chunk1);
+        check(&mut managed_state, &col_types, &col1, &col2);
+
+        // `BtreeMap` in state
+        let col1 = [1, 2, 3, 4, 5];
+        let col2 = [6, 5, 4, 9, 8];
+        let data_chunk2 = DataChunk::from_pretty(
+            "I I
+             5 8
+             4 9",
+        );
+        insert_chunk(&mut managed_state, &pk_indices, &data_chunk2);
+        check(&mut managed_state, &col_types, &col1, &col2);
+    }
 }

src/stream/src/executor/managed_state/join/join_row_set.rs

@@ -0,0 +1,113 @@
+// Copyright 2023 RisingWave Labs
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::collections::btree_map::OccupiedError as BTreeMapOccupiedError;
+use std::collections::BTreeMap;
+use std::fmt::Debug;
+use std::mem;
+
+use auto_enums::auto_enum;
+use enum_as_inner::EnumAsInner;
+
+#[derive(Debug, EnumAsInner)]
+pub enum JoinRowSet<K, V> {
+    BTree(BTreeMap<K, V>),
+    Vec(Vec<(K, V)>),
+}
+
+impl<K, V> Default for JoinRowSet<K, V> {
+    fn default() -> Self {
+        Self::Vec(vec![])
+    }
+}
+
+pub struct VecOccupiedError<'a, K, V> {
+    key: &'a K,
+    old_value: &'a V,
+    new_value: V,
+}
+
+impl<'a, K: Debug, V: Debug> Debug for VecOccupiedError<'a, K, V> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("VecOccupiedError")
+            .field("key", &self.key)
+            .field("old_value", &self.old_value)
+            .field("new_value", &self.new_value)
+            .finish()
+    }
+}
+
+#[derive(Debug)]
+pub enum JoinRowSetOccupiedError<'a, K: Ord, V> {
+    BTree(BTreeMapOccupiedError<'a, K, V>),
+    Vec(VecOccupiedError<'a, K, V>),
+}
+
+impl<K: Ord + Debug, V: Debug> JoinRowSet<K, V> {
+    pub fn try_insert(
+        &mut self,
+        key: K,
+        value: V,
+    ) -> Result<&'_ mut V, JoinRowSetOccupiedError<'_, K, V>> {
+        const MAX_VEC_SIZE: usize = 4;
+
+        if let Self::Vec(inner) = self && inner.len() >= MAX_VEC_SIZE{
+            let btree = BTreeMap::from_iter(inner.drain(..));
+            mem::swap(self, &mut Self::BTree(btree));
+        }
+
+        match self {
+            Self::BTree(inner) => inner
+                .try_insert(key, value)
+                .map_err(JoinRowSetOccupiedError::BTree),
+            Self::Vec(inner) => {
+                if let Some(pos) = inner.iter().position(|elem| elem.0 == key) {
+                    return Err(JoinRowSetOccupiedError::Vec(VecOccupiedError {
+                        key: &inner[pos].0,
+                        old_value: &inner[pos].1,
+                        new_value: value,
+                    }));
+                } else {
+                    inner.push((key, value));
+                    return Ok(&mut inner.last_mut().unwrap().1);
+                }
+            }
+        }
+    }
+
+    pub fn remove(&mut self, key: &K) -> Option<V> {
+        match self {
+            Self::BTree(inner) => inner.remove(key),
+            Self::Vec(inner) => inner
+                .iter()
+                .position(|elem| &elem.0 == key)
+                .map(|pos| inner.remove(pos).1),
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        match self {
+            Self::BTree(inner) => inner.len(),
+            Self::Vec(inner) => inner.len(),
+        }
+    }
+
+    #[auto_enum(Iterator)]
+    pub fn values_mut(&mut self) -> impl Iterator<Item = &'_ mut V> {
+        match self {
+            Self::BTree(inner) => inner.iter_mut().map(|(_, v)| v),
+            Self::Vec(inner) => inner.iter_mut().map(|(_, v)| v),
+        }
+    }
+}

src/stream/src/executor/managed_state/join/mod.rs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 mod join_entry_state;
+mod join_row_set;
 
 use std::alloc::Global;
 use std::ops::{Bound, Deref, DerefMut};