fix(cubesql): Simplify push-down-limit-filter rule to avoid double limit

Author: mcheshkov

rust/cubesql/cubesql/src/compile/rewrite/rules/filters.rs

@@ -16,12 +16,11 @@ use crate::{
         transforming_rewrite, transforming_rewrite_with_root, udf_expr, udf_expr_var_arg,
         udf_fun_expr_args, udf_fun_expr_args_empty_tail, BetweenExprNegated, BinaryExprOp,
         CastExprDataType, ChangeUserMemberValue, ColumnExprColumn, CubeScanAliasToCube,
-        CubeScanLimit, FilterMemberMember, FilterMemberOp, FilterMemberValues, FilterOpOp,
+        FilterMemberMember, FilterMemberOp, FilterMemberValues, FilterOpOp,
         FilterReplacerAliasToCube, FilterReplacerAliases, InListExprNegated, LikeExprEscapeChar,
-        LikeExprNegated, LimitFetch, LimitSkip, ListPattern, ListType, LiteralExprValue,
-        LogicalPlanLanguage, SegmentMemberMember, TimeDimensionDateRange,
-        TimeDimensionDateRangeReplacerDateRange, TimeDimensionDateRangeReplacerMember,
-        TimeDimensionGranularity, TimeDimensionName,
+        LikeExprNegated, ListPattern, ListType, LiteralExprValue, LogicalPlanLanguage,
+        SegmentMemberMember, TimeDimensionDateRange, TimeDimensionDateRangeReplacerDateRange,
+        TimeDimensionDateRangeReplacerMember, TimeDimensionGranularity, TimeDimensionName,
     },
     config::ConfigObj,
     transport::{ext::V1CubeMetaExt, MemberType, MetaContext},
@@ -131,27 +130,22 @@ impl RewriteRules for FilterRules {
                     ),
                 ),
                 limit(
-                    "?new_limit_skip",
-                    "?new_limit_fetch",
+                    "LimitSkip:None",
+                    "LimitFetch:0",
                     cube_scan(
                         "?source_table_name",
                         "?members",
                         "?filters",
                         "?order",
-                        "?new_limit",
+                        "?limit",
                         "?offset",
                         "?split",
                         "?can_pushdown_join",
                         "?wrapped",
                         "?ungrouped",
                     ),
                 ),
-                self.push_down_limit_filter(
-                    "?literal_false",
-                    "?new_limit",
-                    "?new_limit_skip",
-                    "?new_limit_fetch",
-                ),
+                self.push_down_limit_filter("?literal_false"),
             ),
             // Transform Filter: Boolean(true)
             // It's safe to push down filter under projection, next filter-truncate-true will truncate it
@@ -2553,31 +2547,13 @@ impl FilterRules {
     fn push_down_limit_filter(
         &self,
         literal_var: &'static str,
-        new_limit_var: &'static str,
-        new_limit_skip_var: &'static str,
-        new_limit_fetch_var: &'static str,
     ) -> impl Fn(&mut CubeEGraph, &mut Subst) -> bool {
         let literal_var = var!(literal_var);
-        let new_limit_var = var!(new_limit_var);
-        let new_limit_skip_var = var!(new_limit_skip_var);
-        let new_limit_fetch_var = var!(new_limit_fetch_var);
         move |egraph, subst| {
             if let Some(ConstantFolding::Scalar(literal_value)) =
                 &egraph[subst[literal_var]].data.constant
             {
                 if let ScalarValue::Boolean(Some(false)) = literal_value {
-                    subst.insert(
-                        new_limit_var,
-                        egraph.add(LogicalPlanLanguage::CubeScanLimit(CubeScanLimit(Some(0)))),
-                    );
-                    subst.insert(
-                        new_limit_skip_var,
-                        egraph.add(LogicalPlanLanguage::LimitSkip(LimitSkip(Some(0)))),
-                    );
-                    subst.insert(
-                        new_limit_fetch_var,
-                        egraph.add(LogicalPlanLanguage::LimitFetch(LimitFetch(Some(0)))),
-                    );
                     return true;
                 }
             }