[repr types] eliminate noop costs (lowering impl)

misc/python/materialize/mzcompose/__init__.py

@@ -83,6 +83,7 @@ def get_minimal_system_parameters(
             "true" if version >= MzVersion.parse_mz("v0.132.0-dev") else "false"
         ),
         "enable_alter_swap": "true",
+        "enable_cast_elimination": "true",
         "enable_columnar_lgalloc": "false",
         "enable_columnation_lgalloc": "false",
         "enable_compute_correction_v2": "true",

src/adapter/src/optimize.rs

@@ -242,6 +242,7 @@ impl From<&OptimizerConfig> for mz_sql::plan::HirToMirConfig {
             enable_new_outer_join_lowering: config.features.enable_new_outer_join_lowering,
             enable_variadic_left_join_lowering: config.features.enable_variadic_left_join_lowering,
             enable_guard_subquery_tablefunc: config.features.enable_guard_subquery_tablefunc,
+            enable_cast_elimination: config.features.enable_cast_elimination,
         }
     }
 }

src/repr/src/optimize.rs

@@ -130,8 +130,12 @@ optimizer_feature_flags!({
     enable_less_reduce_in_eqprop: bool,
     // See the feature flag of the same name.
     enable_dequadratic_eqprop_map: bool,
+    // See the feature flag of the same name.
     enable_fast_path_plan_insights: bool,
+    // See the feature flag of the same name.
     enable_repr_typecheck: bool,
+    // See the feature flag of the same name.
+    enable_cast_elimination: bool,
 });
 
 /// A trait used to implement layered config construction.

src/sql/src/plan/lowering.rs

@@ -139,6 +139,7 @@ pub struct Config {
     /// Enable outer join lowering implemented in database-issues#7561.
     pub enable_variadic_left_join_lowering: bool,
     pub enable_guard_subquery_tablefunc: bool,
+    pub enable_cast_elimination: bool,
 }
 
 impl From<&SystemVars> for Config {
@@ -147,6 +148,7 @@ impl From<&SystemVars> for Config {
             enable_new_outer_join_lowering: vars.enable_new_outer_join_lowering(),
             enable_variadic_left_join_lowering: vars.enable_variadic_left_join_lowering(),
             enable_guard_subquery_tablefunc: vars.enable_guard_subquery_tablefunc(),
+            enable_cast_elimination: vars.enable_cast_elimination(),
         }
     }
 }
@@ -969,6 +971,13 @@ impl HirScalarExpr {
                     panic!("cannot decorrelate expression with unbound parameters")
                 }
                 CallUnmaterializable(func, _name) => SS::CallUnmaterializable(func),
+                CallUnary {
+                    func: func::UnaryFunc::CastVarCharToString(_),
+                    expr,
+                    name: _,
+                } if context.config.enable_cast_elimination => {
+                    expr.applied_to(id_gen, col_map, cte_map, inner, subquery_map, context)?
+                }
                 CallUnary {
                     func,
                     expr,

src/sql/src/plan/statement/ddl.rs

@@ -4914,6 +4914,7 @@ pub fn unplan_create_cluster(
                 enable_eq_classes_withholding_errors: _,
                 enable_fast_path_plan_insights: _,
                 enable_repr_typecheck: _,
+                enable_cast_elimination: _,
             } = optimizer_feature_overrides;
             // The ones from above that don't occur below are not wired up to cluster features.
             let features_extracted = ClusterFeatureExtracted {

src/sql/src/plan/statement/dml.rs

@@ -639,6 +639,7 @@ impl TryFrom<ExplainPlanOptionExtracted> for ExplainConfig {
                 enable_eq_classes_withholding_errors: Default::default(),
                 enable_fast_path_plan_insights: Default::default(),
                 enable_repr_typecheck: Default::default(),
+                enable_cast_elimination: Default::default(),
             },
         })
     }

src/sql/src/session/vars/definitions.rs

@@ -2230,6 +2230,12 @@ feature_flags!(
         default: false,
         enable_for_item_parsing: false,
     },
+    {
+        name: enable_cast_elimination,
+        desc: "Allow the optimizer to eliminate noop casts between values of equivalent representation types.",
+        default: false,
+        enable_for_item_parsing: false,
+    },
 );
 
 impl From<&super::SystemVars> for OptimizerFeatures {
@@ -2254,6 +2260,7 @@ impl From<&super::SystemVars> for OptimizerFeatures {
             enable_eq_classes_withholding_errors: vars.enable_eq_classes_withholding_errors(),
             enable_fast_path_plan_insights: vars.enable_fast_path_plan_insights(),
             enable_repr_typecheck: vars.enable_repr_typecheck(),
+            enable_cast_elimination: vars.enable_cast_elimination(),
         }
     }
 }

test/sqllogictest/freshmart.slt

@@ -291,7 +291,7 @@ Explained Query:
           Get l6
   Return
     Project (#0{product_id}, #13, #11{last_update_time})
-      Map (case when (#8) IS NULL then null else #7 end, (((((#2{base_price} * case when (#3{popularity_rank} <= 3) then 1.2 else case when ((#3{popularity_rank} <= 10) AND (#3{popularity_rank} >= 4)) then 1.1 else 0.9 end end) * coalesce((1 - (#5{promotion_discount} / 100)), 1)) * case when (#12{stock_rank} <= 3) then 1.1 else case when ((#12 <= 10) AND (#12 >= 4)) then 1.05 else 1 end end) * case when (#2{base_price} > #4{avg_price}) then (1 + ((#2{base_price} - #4{avg_price}) / #4{avg_price})) else (1 - ((#4{avg_price} - #2{base_price}) / #4{avg_price})) end) * case when ilike["%cheap%"](varchar_to_text(#1{product_name})) then 0.8 else 1 end))
+      Map (case when (#8) IS NULL then null else #7 end, (((((#2{base_price} * case when (#3{popularity_rank} <= 3) then 1.2 else case when ((#3{popularity_rank} <= 10) AND (#3{popularity_rank} >= 4)) then 1.1 else 0.9 end end) * coalesce((1 - (#5{promotion_discount} / 100)), 1)) * case when (#12{stock_rank} <= 3) then 1.1 else case when ((#12 <= 10) AND (#12 >= 4)) then 1.05 else 1 end end) * case when (#2{base_price} > #4{avg_price}) then (1 + ((#2{base_price} - #4{avg_price}) / #4{avg_price})) else (1 - ((#4{avg_price} - #2{base_price}) / #4{avg_price})) end) * case when ilike["%cheap%"](#1{product_name}) then 0.8 else 1 end))
         Join on=(#0{product_id} = #6{product_id} = #9{product_id} = #10{product_id}) type=delta
           ArrangeBy keys=[[#0{product_id}]]
             Get l6

test/sqllogictest/ldbc_bi.slt

@@ -2018,7 +2018,7 @@ Explained Query:
             ArrangeBy keys=[[#0{rootpostlanguage}]] // { arity: 1 }
               Distinct project=[#0{rootpostlanguage}] // { arity: 1 }
                 Project (#0{rootpostlanguage}) // { arity: 1 }
-                  Filter (#0{rootpostlanguage} = varchar_to_text(#1{right_col0_0})) // { arity: 2 }
+                  Filter (#0{rootpostlanguage} = #1{right_col0_0}) // { arity: 2 }
                     FlatMap unnest_array({"es", "ta", "pt"}) // { arity: 2 }
                       Distinct project=[#0{rootpostlanguage}] // { arity: 1 }
                         Project (#13{rootpostlanguage}) // { arity: 1 }

test/sqllogictest/ldbc_bi_eager.slt

@@ -2025,7 +2025,7 @@ Explained Query:
             ArrangeBy keys=[[#0{rootpostlanguage}]] // { arity: 1 }
               Distinct project=[#0{rootpostlanguage}] // { arity: 1 }
                 Project (#0{rootpostlanguage}) // { arity: 1 }
-                  Filter (#0{rootpostlanguage} = varchar_to_text(#1{right_col0_0})) // { arity: 2 }
+                  Filter (#0{rootpostlanguage} = #1{right_col0_0}) // { arity: 2 }
                     FlatMap unnest_array({"es", "ta", "pt"}) // { arity: 2 }
                       Distinct project=[#0{rootpostlanguage}] // { arity: 1 }
                         Project (#13{rootpostlanguage}) // { arity: 1 }

test/sqllogictest/tpch_create_index.slt

@@ -282,7 +282,7 @@ materialize.public.q02:
         ReadIndex on=region pk_region_regionkey=[delta join lookup] // { arity: 3 }
     cte l4 =
       Project (#0{p_partkey}, #2{p_mfgr}, #10{s_name}, #11{s_address}, #13{s_phone}..=#15{s_comment}, #19{ps_supplycost}, #22{n_name}) // { arity: 9 }
-        Filter (#5{p_size} = 15) AND (#26{r_name} = "EUROPE") AND like["%BRASS"](varchar_to_text(#4{p_type})) // { arity: 28 }
+        Filter like["%BRASS"](#4{p_type}) AND (#5{p_size} = 15) AND (#26{r_name} = "EUROPE") // { arity: 28 }
           Join on=(#0{p_partkey} = #16{ps_partkey} AND #9{s_suppkey} = #17{ps_suppkey} AND #12{s_nationkey} = #21{n_nationkey} AND #23{n_regionkey} = #25{r_regionkey}) type=delta // { arity: 28 }
             implementation
               %0:part » %2:l1[#0{ps_partkey}]KA » %1:l0[#0{s_suppkey}]KA » %3:l2[#0{n_nationkey}]KA » %4:l3[#0{r_regionkey}]KAef
@@ -746,7 +746,7 @@ materialize.public.q08:
     Map ((#1{sum} / #2{sum})) // { arity: 4 }
       Reduce group_by=[extract_year_d(#2{o_orderdate})] aggregates=[sum(case when (#3{n_name} = "BRAZIL") then (#0{l_extendedprice} * (1 - #1{l_discount})) else 0 end), sum((#0{l_extendedprice} * (1 - #1{l_discount})))] // { arity: 3 }
         Project (#21{l_extendedprice}, #22{l_discount}, #36{o_orderdate}, #54{n_name}) // { arity: 4 }
-          Filter (#58{r_name} = "AMERICA") AND (#36{o_orderdate} <= 1996-12-31) AND (#36{o_orderdate} >= 1995-01-01) AND ("ECONOMY ANODIZED STEEL" = varchar_to_text(#4{p_type})) // { arity: 60 }
+          Filter (#4{p_type} = "ECONOMY ANODIZED STEEL") AND (#58{r_name} = "AMERICA") AND (#36{o_orderdate} <= 1996-12-31) AND (#36{o_orderdate} >= 1995-01-01) // { arity: 60 }
             Join on=(#0{p_partkey} = #17{l_partkey} AND #9{s_suppkey} = #18{l_suppkey} AND #12{s_nationkey} = #53{n_nationkey} AND #16{l_orderkey} = #32{o_orderkey} AND #33{o_custkey} = #41{c_custkey} AND #44{c_nationkey} = #49{n_nationkey} AND #51{n_regionkey} = #57{r_regionkey}) type=delta // { arity: 60 }
               implementation
                 %0:part » %2:lineitem[#1{l_partkey}]KA » %3:orders[#0{o_orderkey}]KAiif » %1:supplier[#0{s_suppkey}]KA » %4:customer[#0{c_custkey}]KA » %5:nation[#0{n_nationkey}]KA » %7:region[#0{r_regionkey}]KAef » %6:nation[#0{n_nationkey}]KA
@@ -843,7 +843,7 @@ materialize.public.q09_primary_idx:
 materialize.public.q09:
   Reduce group_by=[#5{n_name}, extract_year_d(#4{o_orderdate})] aggregates=[sum(((#1{l_extendedprice} * (1 - #2{l_discount})) - (#3{ps_supplycost} * #0{l_quantity})))] // { arity: 3 }
     Project (#20{l_quantity}..=#22{l_discount}, #35{ps_supplycost}, #41{o_orderdate}, #47{n_name}) // { arity: 6 }
-      Filter like["%green%"](varchar_to_text(#1{p_name})) // { arity: 50 }
+      Filter like["%green%"](#1{p_name}) // { arity: 50 }
         Join on=(#0{p_partkey} = #17{l_partkey} = #32{ps_partkey} AND #9{s_suppkey} = #18{l_suppkey} = #33{ps_suppkey} AND #12{s_nationkey} = #46{n_nationkey} AND #16{l_orderkey} = #37{o_orderkey}) type=delta // { arity: 50 }
           implementation
             %0:part » %2:lineitem[#1{l_partkey}]KA » %3:partsupp[#0{ps_partkey}, #1{ps_suppkey}]KKA » %1:supplier[#0{s_suppkey}]KA » %4:orders[#0{o_orderkey}]KA » %5:nation[#0{n_nationkey}]KA
@@ -1147,7 +1147,7 @@ materialize.public.q13:
         ReadIndex on=customer pk_customer_custkey=[differential join] // { arity: 8 }
     cte l1 =
       Project (#0{c_custkey}, #8{o_orderkey}) // { arity: 2 }
-        Filter NOT(like["%special%requests%"](varchar_to_text(#16{o_comment}))) // { arity: 17 }
+        Filter NOT(like["%special%requests%"](#16{o_comment})) // { arity: 17 }
           Join on=(#0{c_custkey} = #9{o_custkey}) type=differential // { arity: 17 }
             implementation
               %1:orders[#1{o_custkey}]KAf » %0:l0[#0{c_custkey}]KAf
@@ -1214,7 +1214,7 @@ materialize.public.q14_primary_idx:
 materialize.public.q14:
   With
     cte l0 =
-      Reduce aggregates=[sum(case when like["PROMO%"](varchar_to_text(#2{p_type})) then (#0{l_extendedprice} * (1 - #1{l_discount})) else 0 end), sum((#0{l_extendedprice} * (1 - #1{l_discount})))] // { arity: 2 }
+      Reduce aggregates=[sum(case when like["PROMO%"](#2{p_type}) then (#0{l_extendedprice} * (1 - #1{l_discount})) else 0 end), sum((#0{l_extendedprice} * (1 - #1{l_discount})))] // { arity: 2 }
         Project (#5{l_extendedprice}, #6{l_discount}, #20{p_type}) // { arity: 3 }
           Filter (#10{l_shipdate} >= 1995-09-01) AND (date_to_timestamp(#10{l_shipdate}) < 1995-10-01 00:00:00) // { arity: 25 }
             Join on=(#1{l_partkey} = #16{p_partkey}) type=differential // { arity: 25 }
@@ -1372,7 +1372,7 @@ materialize.public.q16:
   With
     cte l0 =
       Project (#1{ps_suppkey}, #8{p_brand}..=#10{p_size}) // { arity: 4 }
-        Filter (#8{p_brand} != "Brand#45") AND NOT(like["MEDIUM POLISHED%"](varchar_to_text(#9{p_type}))) AND ((#10{p_size} = 3) OR (#10{p_size} = 9) OR (#10{p_size} = 14) OR (#10{p_size} = 19) OR (#10{p_size} = 23) OR (#10{p_size} = 36) OR (#10{p_size} = 45) OR (#10{p_size} = 49)) // { arity: 14 }
+        Filter (#8{p_brand} != "Brand#45") AND NOT(like["MEDIUM POLISHED%"](#9{p_type})) AND ((#10{p_size} = 3) OR (#10{p_size} = 9) OR (#10{p_size} = 14) OR (#10{p_size} = 19) OR (#10{p_size} = 23) OR (#10{p_size} = 36) OR (#10{p_size} = 45) OR (#10{p_size} = 49)) // { arity: 14 }
           Join on=(#0{ps_partkey} = #5{p_partkey}) type=differential // { arity: 14 }
             implementation
               %1:part[#0{p_partkey}]KAef » %0:partsupp[#0{ps_partkey}]KAef
@@ -1405,7 +1405,7 @@ materialize.public.q16:
                           Get l1 // { arity: 1 }
                         ArrangeBy keys=[[]] // { arity: 1 }
                           Project (#0{s_suppkey}) // { arity: 1 }
-                            Filter like["%Customer%Complaints%"](varchar_to_text(#6{s_comment})) // { arity: 7 }
+                            Filter like["%Customer%Complaints%"](#6{s_comment}) // { arity: 7 }
                               ReadIndex on=supplier pk_supplier_suppkey=[*** full scan ***] // { arity: 7 }
               Get l1 // { arity: 1 }
 
@@ -1764,7 +1764,7 @@ materialize.public.q20:
           ArrangeBy keys=[[#0{p_partkey}]] // { arity: 1 }
             Distinct project=[#0{p_partkey}] // { arity: 1 }
               Project (#0{p_partkey}) // { arity: 1 }
-                Filter (#0{p_partkey}) IS NOT NULL AND like["forest%"](varchar_to_text(#1{p_name})) // { arity: 9 }
+                Filter like["forest%"](#1{p_name}) AND (#0{p_partkey}) IS NOT NULL // { arity: 9 }
                   ReadIndex on=part pk_part_partkey=[*** full scan ***] // { arity: 9 }
   Return // { arity: 2 }
     Project (#1{s_name}, #2{s_address}) // { arity: 2 }