From 0cef3bf31ca8995b675ee860eb08da9e5ad17f3e Mon Sep 17 00:00:00 2001
From: David Hall <david.hall@mariadb.com>
Date: Thu, 29 Nov 2018 13:31:12 -0600
Subject: [PATCH] MCOL-1983 Have regr_intercept, regr_slope and regr_r2 return
 NULL for 1 or 0 rows in set

---
 utils/regr/regr_intercept.cpp    | 2 +-
 utils/regr/regr_r2.cpp           | 2 +-
 utils/regr/regr_slope.cpp        | 2 +-
 utils/windowfunction/wf_udaf.cpp | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/utils/regr/regr_intercept.cpp b/utils/regr/regr_intercept.cpp
index 6d4c35a47..011488d9d 100644
--- a/utils/regr/regr_intercept.cpp
+++ b/utils/regr/regr_intercept.cpp
@@ -139,7 +139,7 @@ mcsv1_UDAF::ReturnCode regr_intercept::evaluate(mcsv1Context* context, static_an
 {
     struct regr_intercept_data* data = (struct regr_intercept_data*)context->getUserData()->data;
     double N = data->cnt;
-    if (N > 0)
+    if (N > 1)
     {
         double sumx = data->sumx;
         double sumy = data->sumy;
diff --git a/utils/regr/regr_r2.cpp b/utils/regr/regr_r2.cpp
index 34e8888e8..96b0ada18 100644
--- a/utils/regr/regr_r2.cpp
+++ b/utils/regr/regr_r2.cpp
@@ -144,7 +144,7 @@ mcsv1_UDAF::ReturnCode regr_r2::evaluate(mcsv1Context* context, static_any::any&
 {
     struct regr_r2_data* data = (struct regr_r2_data*)context->getUserData()->data;
     double N = data->cnt;
-    if (N > 0)
+    if (N > 1)
     {
         double sumx = data->sumx;
         double sumy = data->sumy;
diff --git a/utils/regr/regr_slope.cpp b/utils/regr/regr_slope.cpp
index da178673a..fdb94795a 100644
--- a/utils/regr/regr_slope.cpp
+++ b/utils/regr/regr_slope.cpp
@@ -139,7 +139,7 @@ mcsv1_UDAF::ReturnCode regr_slope::evaluate(mcsv1Context* context, static_any::a
 {
     struct regr_slope_data* data = (struct regr_slope_data*)context->getUserData()->data;
     double N = data->cnt;
-    if (N > 0)
+    if (N > 1)
     {
         // COVAR_POP(y, x) / VAR_POP(x)
         double sumx = data->sumx;
diff --git a/utils/windowfunction/wf_udaf.cpp b/utils/windowfunction/wf_udaf.cpp
index 2b7e28abc..5986c2872 100644
--- a/utils/windowfunction/wf_udaf.cpp
+++ b/utils/windowfunction/wf_udaf.cpp
@@ -84,7 +84,6 @@ void WF_udaf::resetData()
     getContext().getFunction()->reset(&getContext());
     fDistinctMap.clear();
     WindowFunctionType::resetData();
-    fValOut.reset();
 }
 
 void WF_udaf::parseParms(const std::vector<execplan::SRCP>& parms)
@@ -709,6 +708,7 @@ void WF_udaf::operator()(int64_t b, int64_t e, int64_t c)
     mcsv1sdk::mcsv1_UDAF::ReturnCode rc;
     uint64_t colOut = fFieldIndex[0];
     bool isNull = false;
+    fValOut.reset();
 
     if ((fFrameUnit == WF__FRAME_ROWS) ||
             (fPrev == -1) ||