Back out "Refactor greatest and least Presto functions using simple f…

…unction API" (facebookincubator#9493)

Summary:
Temporarily reverting as the switch to using a simple function implementation for 'greatest' and 'least' functions are causing issues registering the UDF for some internal use-cases.

Pull Request resolved: facebookincubator#9493

Original commit changeset: c389bad91197

Original Phabricator Diff: D55793910n

Reviewed By: wqfish, bikramSingh91

Differential Revision: D56160832

fbshipit-source-id: f7550b819f8b8f276b88cb33c52de05807a4f2d2

velox/functions/prestosql/CMakeLists.txt

@@ -34,6 +34,7 @@ add_library(
   FindFirst.cpp
   FromUnixTime.cpp
   FromUtf8.cpp
+  GreatestLeast.cpp
   InPredicate.cpp
   JsonFunctions.cpp
   Map.cpp

velox/functions/prestosql/GreatestLeast.cpp

@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <cmath>
+#include <type_traits>
+#include "velox/common/base/Exceptions.h"
+#include "velox/expression/Expr.h"
+#include "velox/expression/VectorFunction.h"
+#include "velox/type/Type.h"
+
+namespace facebook::velox::functions {
+
+namespace {
+
+template <bool>
+class ExtremeValueFunction;
+
+using LeastFunction = ExtremeValueFunction<true>;
+using GreatestFunction = ExtremeValueFunction<false>;
+
+/**
+ * This class implements two functions:
+ *
+ * greatest(value1, value2, ..., valueN) → [same as input]
+ * Returns the largest of the provided values.
+ *
+ * least(value1, value2, ..., valueN) → [same as input]
+ * Returns the smallest of the provided values.
+ **/
+template <bool isLeast>
+class ExtremeValueFunction : public exec::VectorFunction {
+ private:
+  template <typename T>
+  bool shouldOverride(const T& currentValue, const T& candidateValue) const {
+    return isLeast ? candidateValue < currentValue
+                   : candidateValue > currentValue;
+  }
+
+  // For double, presto should throw error if input is Nan
+  template <typename T>
+  void checkNan(const T& value) const {
+    if constexpr (std::is_same_v<T, TypeTraits<TypeKind::DOUBLE>::NativeType>) {
+      if (std::isnan(value)) {
+        VELOX_USER_FAIL(
+            "Invalid argument to {}: NaN", isLeast ? "least()" : "greatest()");
+      }
+    }
+  }
+
+  template <typename T>
+  void applyTyped(
+      const SelectivityVector& rows,
+      const std::vector<VectorPtr>& args,
+      const TypePtr& outputType,
+      exec::EvalCtx& context,
+      VectorPtr& result) const {
+    context.ensureWritable(rows, outputType, result);
+    result->clearNulls(rows);
+
+    auto* flatResult = result->as<FlatVector<T>>();
+    BufferPtr resultValues = flatResult->mutableValues(rows.end());
+    T* __restrict rawResult = resultValues->asMutable<T>();
+
+    exec::DecodedArgs decodedArgs(rows, args, context);
+
+    std::set<size_t> usedInputs;
+    context.applyToSelectedNoThrow(rows, [&](int row) {
+      size_t valueIndex = 0;
+
+      T currentValue = decodedArgs.at(0)->valueAt<T>(row);
+      checkNan(currentValue);
+
+      for (auto i = 1; i < args.size(); ++i) {
+        auto candidateValue = decodedArgs.at(i)->template valueAt<T>(row);
+        checkNan(candidateValue);
+
+        if constexpr (isLeast) {
+          if (candidateValue < currentValue) {
+            currentValue = candidateValue;
+            valueIndex = i;
+          }
+        } else {
+          if (candidateValue > currentValue) {
+            currentValue = candidateValue;
+            valueIndex = i;
+          }
+        }
+      }
+      usedInputs.insert(valueIndex);
+
+      if constexpr (std::is_same_v<bool, T>) {
+        flatResult->set(row, currentValue);
+      } else {
+        rawResult[row] = currentValue;
+      }
+    });
+
+    if constexpr (std::is_same_v<T, StringView>) {
+      for (auto index : usedInputs) {
+        flatResult->acquireSharedStringBuffers(args[index].get());
+      }
+    }
+  }
+
+ public:
+  void apply(
+      const SelectivityVector& rows,
+      std::vector<VectorPtr>& args,
+      const TypePtr& outputType,
+      exec::EvalCtx& context,
+      VectorPtr& result) const override {
+    switch (outputType.get()->kind()) {
+      case TypeKind::BOOLEAN:
+        applyTyped<bool>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::TINYINT:
+        applyTyped<int8_t>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::SMALLINT:
+        applyTyped<int16_t>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::INTEGER:
+        applyTyped<int32_t>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::BIGINT:
+        applyTyped<int64_t>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::HUGEINT:
+        applyTyped<int128_t>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::REAL:
+        applyTyped<float>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::DOUBLE:
+        applyTyped<double>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::VARCHAR:
+        applyTyped<StringView>(rows, args, outputType, context, result);
+        return;
+      case TypeKind::TIMESTAMP:
+        applyTyped<Timestamp>(rows, args, outputType, context, result);
+        return;
+      default:
+        VELOX_FAIL(
+            "Unsupported input type for {}: {}",
+            isLeast ? "least()" : "greatest()",
+            outputType->toString());
+    }
+  }
+
+  static std::vector<std::shared_ptr<exec::FunctionSignature>> signatures() {
+    const std::vector<std::string> types = {
+        "boolean",
+        "tinyint",
+        "smallint",
+        "integer",
+        "bigint",
+        "double",
+        "real",
+        "varchar",
+        "timestamp",
+        "date",
+    };
+    std::vector<std::shared_ptr<exec::FunctionSignature>> signatures;
+    for (const auto& type : types) {
+      signatures.emplace_back(exec::FunctionSignatureBuilder()
+                                  .returnType(type)
+                                  .argumentType(type)
+                                  .variableArity()
+                                  .build());
+    }
+    signatures.emplace_back(exec::FunctionSignatureBuilder()
+                                .integerVariable("precision")
+                                .integerVariable("scale")
+                                .returnType("DECIMAL(precision, scale)")
+                                .argumentType("DECIMAL(precision, scale)")
+                                .variableArity()
+                                .build());
+    return signatures;
+  }
+};
+} // namespace
+
+VELOX_DECLARE_VECTOR_FUNCTION(
+    udf_least,
+    LeastFunction::signatures(),
+    std::make_unique<LeastFunction>());
+
+VELOX_DECLARE_VECTOR_FUNCTION(
+    udf_greatest,
+    GreatestFunction::signatures(),
+    std::make_unique<GreatestFunction>());
+
+} // namespace facebook::velox::functions

velox/functions/prestosql/registration/GeneralFunctionsRegistration.cpp

@@ -17,35 +17,9 @@
 #include "velox/functions/Registerer.h"
 #include "velox/functions/lib/IsNull.h"
 #include "velox/functions/prestosql/Cardinality.h"
-#include "velox/functions/prestosql/GreatestLeast.h"
 #include "velox/functions/prestosql/InPredicate.h"
 
 namespace facebook::velox::functions {
-
-template <typename T>
-inline void registerGreatestLeastFunction(const std::string& prefix) {
-  registerFunction<ParameterBinder<GreatestFunction, T>, T, T, Variadic<T>>(
-      {prefix + "greatest"});
-
-  registerFunction<ParameterBinder<LeastFunction, T>, T, T, Variadic<T>>(
-      {prefix + "least"});
-}
-
-inline void registerAllGreatestLeastFunctions(const std::string& prefix) {
-  registerGreatestLeastFunction<bool>(prefix);
-  registerGreatestLeastFunction<int8_t>(prefix);
-  registerGreatestLeastFunction<int16_t>(prefix);
-  registerGreatestLeastFunction<int32_t>(prefix);
-  registerGreatestLeastFunction<int64_t>(prefix);
-  registerGreatestLeastFunction<float>(prefix);
-  registerGreatestLeastFunction<double>(prefix);
-  registerGreatestLeastFunction<Varchar>(prefix);
-  registerGreatestLeastFunction<LongDecimal<P1, S1>>(prefix);
-  registerGreatestLeastFunction<ShortDecimal<P1, S1>>(prefix);
-  registerGreatestLeastFunction<Date>(prefix);
-  registerGreatestLeastFunction<Timestamp>(prefix);
-}
-
 extern void registerSubscriptFunction(
     const std::string& name,
     bool enableCaching);
@@ -73,9 +47,11 @@ void registerGeneralFunctions(const std::string& prefix) {
   VELOX_REGISTER_VECTOR_FUNCTION(udf_transform, prefix + "transform");
   VELOX_REGISTER_VECTOR_FUNCTION(udf_reduce, prefix + "reduce");
   VELOX_REGISTER_VECTOR_FUNCTION(udf_array_filter, prefix + "filter");
-  VELOX_REGISTER_VECTOR_FUNCTION(udf_typeof, prefix + "typeof");
 
-  registerAllGreatestLeastFunctions(prefix);
+  VELOX_REGISTER_VECTOR_FUNCTION(udf_least, prefix + "least");
+  VELOX_REGISTER_VECTOR_FUNCTION(udf_greatest, prefix + "greatest");
+
+  VELOX_REGISTER_VECTOR_FUNCTION(udf_typeof, prefix + "typeof");
 
   registerFunction<CardinalityFunction, int64_t, Array<Any>>(
       {prefix + "cardinality"});