define the needed methods in GroupAccumulator and GroupValues.

Author: Rachelint

datafusion/expr-common/src/groups_accumulator.rs

@@ -250,4 +250,30 @@ pub trait GroupsAccumulator: Send {
     /// This function is called once per batch, so it should be `O(n)` to
     /// compute, not `O(num_groups)`
     fn size(&self) -> usize;
+
+    /// Returns `true` if this accumulator supports blocked groups.
+    fn supports_blocked_groups(&self) -> bool {
+        false
+    }
+
+    /// Alter the block size in the accumulator
+    ///
+    /// If the target block size is `None`, it will use a single big
+    /// block(can think it a `Vec`) to manage the state.
+    ///
+    /// If the target block size` is `Some(blk_size)`, it will try to
+    /// set the block size to `blk_size`, and the try will only success
+    /// when the accumulator has supported blocked mode.
+    ///
+    /// NOTICE: After altering block size, all data in previous will be cleared.
+    ///
+    fn alter_block_size(&mut self, block_size: Option<usize>) -> Result<()> {
+        if block_size.is_some() {
+            return Err(DataFusionError::NotImplemented(
+                "this accumulator doesn't support blocked mode yet".to_string(),
+            ));
+        }
+
+        Ok(())
+    }
 }

datafusion/physical-plan/src/aggregates/group_values/mod.rs

@@ -110,6 +110,32 @@ pub(crate) trait GroupValues: Send {
 
     /// Clear the contents and shrink the capacity to the size of the batch (free up memory usage)
     fn clear_shrink(&mut self, batch: &RecordBatch);
+
+    /// Returns `true` if this accumulator supports blocked groups.
+    fn supports_blocked_groups(&self) -> bool {
+        false
+    }
+
+    /// Alter the block size in the `group values`
+    ///
+    /// If the target block size is `None`, it will use a single big
+    /// block(can think it a `Vec`) to manage the state.
+    ///
+    /// If the target block size` is `Some(blk_size)`, it will try to
+    /// set the block size to `blk_size`, and the try will only success
+    /// when the `group values` has supported blocked mode.
+    ///
+    /// NOTICE: After altering block size, all data in previous will be cleared.
+    ///
+    fn alter_block_size(&mut self, block_size: Option<usize>) -> Result<()> {
+        if block_size.is_some() {
+            return Err(DataFusionError::NotImplemented(
+                "this group values doesn't support blocked mode yet".to_string(),
+            ));
+        }
+
+        Ok(())
+    }
 }
 
 /// Return a specialized implementation of [`GroupValues`] for the given schema.