[GitHub] [arrow-datafusion] rdettai commented on a change in pull request #1063: Optimize count agg expr with null column statistics

[GitBox <gi...@apache.org>]

rdettai commented on a change in pull request #1063:
URL: https://github.com/apache/arrow-datafusion/pull/1063#discussion_r719466893



##########
File path: datafusion/src/physical_optimizer/aggregate_statistics.rs
##########
@@ -153,6 +159,37 @@ fn take_optimizable_count(
     None
 }
 
+fn take_optimizable_count_with_nulls(
+    agg_expr: &dyn AggregateExpr,
+    stats: &Statistics,
+) -> Option<(ScalarValue, String)> {
+    if let (Some(num_rows), Some(col_stats), Some(casted_expr)) = (
+        stats.num_rows,
+        &stats.column_statistics,
+        agg_expr.as_any().downcast_ref::<expressions::Min>(),
+    ) {
+        if casted_expr.expressions().len() == 1 {
+            // TODO optimize with exprs other than Column
+            if let Some(col_expr) = casted_expr.expressions()[0]
+                .as_any()
+                .downcast_ref::<expressions::Column>()
+            {
+                if let ColumnStatistics {
+                    null_count: Some(val),
+                    ..
+                } = &col_stats[col_expr.index()]
+                {
+                    return Some((
+                        ScalarValue::UInt64(Some((num_rows - val) as u64)),
+                        "COUNT(Uint8(1))".to_string(),

Review comment:
       Shouldn't this be the column name instead of `UInt8`?




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: github-unsubscribe@arrow.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org