From 541cd638ba7b4bbbfbd3d01aea7c5a7db0f3044a Mon Sep 17 00:00:00 2001
From: hcz <h.cz@qq.com>
Date: Fri, 24 Apr 2020 16:33:09 +0800
Subject: [PATCH] Fix overflow in simpleLinearRegression

---
 .../AggregateFunctionSimpleLinearRegression.h | 26 +++++++++----------
 .../0_stateless/00917_least_sqr.reference     |  1 +
 tests/queries/0_stateless/00917_least_sqr.sql |  2 +-
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/AggregateFunctions/AggregateFunctionSimpleLinearRegression.h b/src/AggregateFunctions/AggregateFunctionSimpleLinearRegression.h
index c9dd22a0649..db4e57c0c6c 100644
--- a/src/AggregateFunctions/AggregateFunctionSimpleLinearRegression.h
+++ b/src/AggregateFunctions/AggregateFunctionSimpleLinearRegression.h
@@ -18,16 +18,16 @@ namespace ErrorCodes
 {
 }
 
-template <typename X, typename Y, typename Ret>
+template <typename T>
 struct AggregateFunctionSimpleLinearRegressionData final
 {
     size_t count = 0;
-    Ret sum_x = 0;
-    Ret sum_y = 0;
-    Ret sum_xx = 0;
-    Ret sum_xy = 0;
+    T sum_x = 0;
+    T sum_y = 0;
+    T sum_xx = 0;
+    T sum_xy = 0;
 
-    void add(X x, Y y)
+    void add(T x, T y)
     {
         count += 1;
         sum_x += x;
@@ -63,20 +63,20 @@ struct AggregateFunctionSimpleLinearRegressionData final
         readBinary(sum_xy, buf);
     }
 
-    Ret getK() const
+    T getK() const
     {
-        Ret divisor = sum_xx * count - sum_x * sum_x;
+        T divisor = sum_xx * count - sum_x * sum_x;
 
         if (divisor == 0)
-            return std::numeric_limits<Ret>::quiet_NaN();
+            return std::numeric_limits<T>::quiet_NaN();
 
         return (sum_xy * count - sum_x * sum_y) / divisor;
     }
 
-    Ret getB(Ret k) const
+    T getB(T k) const
     {
         if (count == 0)
-            return std::numeric_limits<Ret>::quiet_NaN();
+            return std::numeric_limits<T>::quiet_NaN();
 
         return (sum_y - k * sum_x) / count;
     }
@@ -86,7 +86,7 @@ struct AggregateFunctionSimpleLinearRegressionData final
 /// Result is a tuple (k, b) for y = k * x + b equation, solved by least squares approximation.
 template <typename X, typename Y, typename Ret = Float64>
 class AggregateFunctionSimpleLinearRegression final : public IAggregateFunctionDataHelper<
-    AggregateFunctionSimpleLinearRegressionData<X, Y, Ret>,
+    AggregateFunctionSimpleLinearRegressionData<Ret>,
     AggregateFunctionSimpleLinearRegression<X, Y, Ret>
 >
 {
@@ -96,7 +96,7 @@ public:
         const Array & params
     ):
         IAggregateFunctionDataHelper<
-            AggregateFunctionSimpleLinearRegressionData<X, Y, Ret>,
+            AggregateFunctionSimpleLinearRegressionData<Ret>,
             AggregateFunctionSimpleLinearRegression<X, Y, Ret>
         > {arguments, params}
     {
diff --git a/tests/queries/0_stateless/00917_least_sqr.reference b/tests/queries/0_stateless/00917_least_sqr.reference
index 8abd62892db..ee1e3115b0e 100644
--- a/tests/queries/0_stateless/00917_least_sqr.reference
+++ b/tests/queries/0_stateless/00917_least_sqr.reference
@@ -6,3 +6,4 @@
 (0,3)
 (nan,nan)
 (nan,nan)
+(100000000,900000000)
diff --git a/tests/queries/0_stateless/00917_least_sqr.sql b/tests/queries/0_stateless/00917_least_sqr.sql
index b6171c216d2..5fa01830231 100644
--- a/tests/queries/0_stateless/00917_least_sqr.sql
+++ b/tests/queries/0_stateless/00917_least_sqr.sql
@@ -6,4 +6,4 @@ select arrayReduce('simpleLinearRegression', [0], [0]);
 select arrayReduce('simpleLinearRegression', [3, 4], [3, 3]);
 select arrayReduce('simpleLinearRegression', [3, 3], [3, 4]);
 select arrayReduce('simpleLinearRegression', emptyArrayUInt8(), emptyArrayUInt8());
-
+select arrayReduce('simpleLinearRegression', [1, 2, 3, 4], [1000000000, 1100000000, 1200000000, 1300000000]);