fix(cubesql): Break cost symmetry for (non)-push-to-Cube WrappedSelect

Without this two different representations can have zero members, different push-to-Cube and same cost.
It could be done in a single cost component, like zero_members_wrapper, but would require to have a complex dispatch instead of add_child

Author: mcheshkov

rust/cubesql/cubesql/src/compile/rewrite/cost.rs

@@ -4,7 +4,7 @@ use crate::{
     compile::rewrite::{
         rules::utils::granularity_str_to_int_order, CubeScanUngrouped, CubeScanWrapped,
         DimensionName, LogicalPlanLanguage, MemberErrorPriority, ScalarUDFExprFun,
-        TimeDimensionGranularity, WrappedSelectUngroupedScan,
+        TimeDimensionGranularity, WrappedSelectPushToCube, WrappedSelectUngroupedScan,
     },
     transport::{MetaContext, V1CubeMetaDimensionExt},
 };
@@ -186,6 +186,11 @@ impl BestCubePlan {
             _ => 0,
         };
 
+        let wrapped_select_non_push_to_cube = match enode {
+            LogicalPlanLanguage::WrappedSelectPushToCube(WrappedSelectPushToCube(false)) => 1,
+            _ => 0,
+        };
+
         let wrapped_select_ungrouped_scan = match enode {
             LogicalPlanLanguage::WrappedSelectUngroupedScan(WrappedSelectUngroupedScan(true)) => 1,
             _ => 0,
@@ -215,6 +220,7 @@ impl BestCubePlan {
             ungrouped_aggregates: 0,
             wrapper_nodes,
             joins,
+            wrapped_select_non_push_to_cube,
             wrapped_select_ungrouped_scan,
             empty_wrappers: 0,
             ast_size_outside_wrapper: 0,
@@ -239,6 +245,7 @@ impl BestCubePlan {
 /// - `member_errors` > `wrapper_nodes` - use SQL push down where possible if cube scan can't be detected
 /// - `non_pushed_down_window` > `wrapper_nodes` - prefer to always push down window functions
 /// - `non_pushed_down_limit_sort` > `wrapper_nodes` - prefer to always push down limit-sort expressions
+/// - `wrapped_select_non_push_to_cube` > `wrapped_select_ungrouped_scan` - otherwise cost would prefer any aggregation, even non-push-to-Cube
 /// - match errors by priority - optimize for more specific errors
 #[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq)]
 pub struct CubePlanCost {
@@ -256,6 +263,7 @@ pub struct CubePlanCost {
     joins: usize,
     wrapper_nodes: i64,
     ast_size_outside_wrapper: usize,
+    wrapped_select_non_push_to_cube: usize,
     wrapped_select_ungrouped_scan: usize,
     filters: i64,
     structure_points: i64,
@@ -382,6 +390,8 @@ impl CubePlanCost {
                 + other.ast_size_outside_wrapper,
             ungrouped_aggregates: self.ungrouped_aggregates + other.ungrouped_aggregates,
             wrapper_nodes: self.wrapper_nodes + other.wrapper_nodes,
+            wrapped_select_non_push_to_cube: self.wrapped_select_non_push_to_cube
+                + other.wrapped_select_non_push_to_cube,
             wrapped_select_ungrouped_scan: self.wrapped_select_ungrouped_scan
                 + other.wrapped_select_ungrouped_scan,
             cube_scan_nodes: self.cube_scan_nodes + other.cube_scan_nodes,
@@ -468,6 +478,7 @@ impl CubePlanCost {
             } + self.ungrouped_aggregates,
             unwrapped_subqueries: self.unwrapped_subqueries,
             wrapper_nodes: self.wrapper_nodes,
+            wrapped_select_non_push_to_cube: self.wrapped_select_non_push_to_cube,
             wrapped_select_ungrouped_scan: self.wrapped_select_ungrouped_scan,
             cube_scan_nodes: self.cube_scan_nodes,
             ast_size_without_alias: self.ast_size_without_alias,

rust/cubesql/cubesql/src/compile/test/test_wrapper.rs

@@ -1417,3 +1417,41 @@ async fn wrapper_agg_dimension_over_limit() {
         .sql
         .contains("\"ungrouped\": true"));
 }
+
+/// Simple wrapper with cast should have explicit members, not zero
+#[tokio::test]
+async fn wrapper_cast_limit_explicit_members() {
+    if !Rewriter::sql_push_down_enabled() {
+        return;
+    }
+    init_testing_logger();
+
+    let query_plan = convert_select_to_query_plan(
+        // language=PostgreSQL
+        r#"
+        SELECT
+            CAST(dim_date0 AS DATE) AS "dim_date0"
+        FROM
+            MultiTypeCube
+        LIMIT 10
+        ;
+        "#
+        .to_string(),
+        DatabaseProtocol::PostgreSQL,
+    )
+    .await;
+
+    let physical_plan = query_plan.as_physical_plan().await.unwrap();
+    println!(
+        "Physical plan: {}",
+        displayable(physical_plan.as_ref()).indent()
+    );
+
+    // Query should mention just a single member
+    let request = query_plan
+        .as_logical_plan()
+        .find_cube_scan_wrapped_sql()
+        .request;
+    assert_eq!(request.measures.unwrap().len(), 1);
+    assert_eq!(request.dimensions.unwrap().len(), 0);
+}