diff --git a/utils/regr/corr.cpp b/utils/regr/corr.cpp
index 4d6768353..85576d1a6 100644
--- a/utils/regr/corr.cpp
+++ b/utils/regr/corr.cpp
@@ -39,11 +39,11 @@ static Add_corr_ToUDAFMap addToMap;
 struct corr_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumx2;  // sum of (x squared)
-  long double sumy;
-  long double sumy2;  // sum of (y squared)
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double varx;
+  long double avgy;
+  long double vary;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode corr::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -76,11 +76,11 @@ mcsv1_UDAF::ReturnCode corr::reset(mcsv1Context* context)
 {
   struct corr_data* data = (struct corr_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumx2 = 0.0;
-  data->sumy = 0.0;
-  data->sumy2 = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->varx = 0.0;
+  data->avgy = 0.0;
+  data->vary = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -90,15 +90,30 @@ mcsv1_UDAF::ReturnCode corr::nextValue(mcsv1Context* context, ColumnDatum* valsI
   double valx = toDouble(valsIn[1]);
   struct corr_data* data = (struct corr_data*)context->getUserData()->data;
 
-  data->sumy += valy;
-  data->sumy2 += valy * valy;
-
-  data->sumx += valx;
-  data->sumx2 += valx * valx;
-
-  data->sumxy += valx * valy;
-
+  long double avgyPrev = data->avgy;
+  long double varyPrev = data->vary;
+  long double avgxPrev = data->avgx;
+  long double varxPrev = data->varx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev += dy / cnt;
+  avgxPrev += dx / cnt;
+
+  varxPrev += dx * (valx - avgxPrev);
+  varyPrev += dy * (valy - avgyPrev);
+
+  cxyPrev += dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->varx = varxPrev;
+  data->vary = varyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -113,12 +128,38 @@ mcsv1_UDAF::ReturnCode corr::subEvaluate(mcsv1Context* context, const UserData*
   struct corr_data* outData = (struct corr_data*)context->getUserData()->data;
   struct corr_data* inData = (struct corr_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumx2 += inData->sumx2;
-  outData->sumy += inData->sumy;
-  outData->sumy2 += inData->sumy2;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outVarx = outData->varx;
+  long double outVary = outData->vary;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inVarx = inData->varx;
+  long double inVary = inData->vary;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+
+  long double resVarx = outVarx + inVarx + deltax * deltax * inCnt * outCnt / resCnt;
+  long double resVary = outVary + inVary + deltay * deltay * inCnt * outCnt / resCnt;
+
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->varx = resVarx;
+  outData->vary = resVary;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -129,19 +170,17 @@ mcsv1_UDAF::ReturnCode corr::evaluate(mcsv1Context* context, static_any::any& va
   double N = data->cnt;
   if (N > 1)
   {
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumx2 = data->sumx2;
-    long double sumy2 = data->sumy2;
-    long double sumxy = data->sumxy;
+    long double varx = data->varx;
+    long double vary = data->vary;
+    long double cxy = data->cxy;
 
-    long double var_popx = (sumx2 - (sumx * sumx / N)) / N;
+    long double var_popx = varx / N;
     if (var_popx <= 0)  // Catch -0
     {
       // When var_popx is 0, NULL is the result.
       return mcsv1_UDAF::SUCCESS;
     }
-    long double var_popy = (sumy2 - (sumy * sumy / N)) / N;
+    long double var_popy = vary / N;
     if (var_popy <= 0)  // Catch -0
     {
       // When var_popy is 0, NULL is the result
@@ -149,8 +188,7 @@ mcsv1_UDAF::ReturnCode corr::evaluate(mcsv1Context* context, static_any::any& va
     }
     long double std_popx = sqrt(var_popx);
     long double std_popy = sqrt(var_popy);
-    long double covar_pop = (sumxy - ((sumx * sumy) / N)) / N;
-    long double corr = covar_pop / (std_popy * std_popx);
+    long double corr = cxy / (std_popy * std_popx * N);
     valOut = static_cast<double>(corr);
   }
   return mcsv1_UDAF::SUCCESS;
@@ -162,14 +200,30 @@ mcsv1_UDAF::ReturnCode corr::dropValue(mcsv1Context* context, ColumnDatum* valsD
   double valx = toDouble(valsDropped[1]);
   struct corr_data* data = (struct corr_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumy2 -= valy * valy;
-
-  data->sumx -= valx;
-  data->sumx2 -= valx * valx;
-
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double varyPrev = data->vary;
+  long double avgxPrev = data->avgx;
+  long double varxPrev = data->varx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev -= dy / cnt;
+  avgxPrev -= dx / cnt;
+
+  varxPrev -= dx * (valx - avgxPrev);
+  varyPrev -= dy * (valy - avgyPrev);
+
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->varx = varxPrev;
+  data->vary = varyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/covar_pop.cpp b/utils/regr/covar_pop.cpp
index 7220dd36e..d24951466 100644
--- a/utils/regr/covar_pop.cpp
+++ b/utils/regr/covar_pop.cpp
@@ -39,9 +39,9 @@ static Add_covar_pop_ToUDAFMap addToMap;
 struct covar_pop_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumy;
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double avgy;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode covar_pop::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -74,9 +74,9 @@ mcsv1_UDAF::ReturnCode covar_pop::reset(mcsv1Context* context)
 {
   struct covar_pop_data* data = (struct covar_pop_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumy = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->avgy = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -86,12 +86,18 @@ mcsv1_UDAF::ReturnCode covar_pop::nextValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsIn[1]);
   struct covar_pop_data* data = (struct covar_pop_data*)context->getUserData()->data;
 
-  data->sumy += valy;
-  data->sumx += valx;
-
-  data->sumxy += valx * valy;
-
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
+  avgyPrev += (valy - avgyPrev)/cnt;
+  avgxPrev += dx / cnt;
+  cxyPrev += dx * (valy - avgyPrev);
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -106,10 +112,27 @@ mcsv1_UDAF::ReturnCode covar_pop::subEvaluate(mcsv1Context* context, const UserD
   struct covar_pop_data* outData = (struct covar_pop_data*)context->getUserData()->data;
   struct covar_pop_data* inData = (struct covar_pop_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumy += inData->sumy;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -120,11 +143,7 @@ mcsv1_UDAF::ReturnCode covar_pop::evaluate(mcsv1Context* context, static_any::an
   double N = data->cnt;
   if (N > 0)
   {
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumxy = data->sumxy;
-
-    long double covar_pop = (sumxy - ((sumx * sumy) / N)) / N;
+    long double covar_pop = data->cxy / N;
     valOut = static_cast<double>(covar_pop);
   }
   return mcsv1_UDAF::SUCCESS;
@@ -136,11 +155,20 @@ mcsv1_UDAF::ReturnCode covar_pop::dropValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsDropped[1]);
   struct covar_pop_data* data = (struct covar_pop_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumx -= valx;
-
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
+
+  avgyPrev -= (valy - avgyPrev) / cnt;
+  avgxPrev -= dx / cnt;
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/covar_samp.cpp b/utils/regr/covar_samp.cpp
index fddcaab51..4369dbca1 100644
--- a/utils/regr/covar_samp.cpp
+++ b/utils/regr/covar_samp.cpp
@@ -39,9 +39,9 @@ static Add_covar_samp_ToUDAFMap addToMap;
 struct covar_samp_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumy;
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double avgy;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode covar_samp::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -74,9 +74,9 @@ mcsv1_UDAF::ReturnCode covar_samp::reset(mcsv1Context* context)
 {
   struct covar_samp_data* data = (struct covar_samp_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumy = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->avgy = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -86,13 +86,18 @@ mcsv1_UDAF::ReturnCode covar_samp::nextValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsIn[1]);
   struct covar_samp_data* data = (struct covar_samp_data*)context->getUserData()->data;
 
-  data->sumy += valy;
-
-  data->sumx += valx;
-
-  data->sumxy += valx * valy;
-
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
+  avgyPrev += (valy - avgyPrev)/cnt;
+  avgxPrev += dx / cnt;
+  cxyPrev += dx * (valy - avgyPrev);
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -107,10 +112,27 @@ mcsv1_UDAF::ReturnCode covar_samp::subEvaluate(mcsv1Context* context, const User
   struct covar_samp_data* outData = (struct covar_samp_data*)context->getUserData()->data;
   struct covar_samp_data* inData = (struct covar_samp_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumy += inData->sumy;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -121,11 +143,7 @@ mcsv1_UDAF::ReturnCode covar_samp::evaluate(mcsv1Context* context, static_any::a
   double N = data->cnt;
   if (N > 1)
   {
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumxy = data->sumxy;
-
-    long double covar_samp = (sumxy - ((sumx * sumy) / N)) / (N - 1);
+    long double covar_samp = data->cxy / (N - 1);
     valOut = static_cast<double>(covar_samp);
   }
   else if (N == 1)
@@ -141,12 +159,19 @@ mcsv1_UDAF::ReturnCode covar_samp::dropValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsDropped[1]);
   struct covar_samp_data* data = (struct covar_samp_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-
-  data->sumx -= valx;
-
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
 
+  avgyPrev -= (valy - avgyPrev) / cnt;
+  avgxPrev -= dx / cnt;
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cxy = cxyPrev;
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/regr_intercept.cpp b/utils/regr/regr_intercept.cpp
index 8dda7c08a..221d4f63d 100644
--- a/utils/regr/regr_intercept.cpp
+++ b/utils/regr/regr_intercept.cpp
@@ -39,10 +39,10 @@ static Add_regr_intercept_ToUDAFMap addToMap;
 struct regr_intercept_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumx2;  // sum of (x squared)
-  long double sumy;
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double cx;
+  long double avgy;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode regr_intercept::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -75,10 +75,10 @@ mcsv1_UDAF::ReturnCode regr_intercept::reset(mcsv1Context* context)
 {
   struct regr_intercept_data* data = (struct regr_intercept_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumx2 = 0.0;
-  data->sumy = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->cx = 0.0;
+  data->avgy = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -88,12 +88,27 @@ mcsv1_UDAF::ReturnCode regr_intercept::nextValue(mcsv1Context* context, ColumnDa
   double valx = toDouble(valsIn[1]);
   struct regr_intercept_data* data = (struct regr_intercept_data*)context->getUserData()->data;
 
-  data->sumy += valy;
-  data->sumx += valx;
-  data->sumx2 += valx * valx;
-
-  data->sumxy += valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev += dy / cnt;
+  avgxPrev += dx / cnt;
+
+  cxPrev += dx * (valx - avgxPrev);
+
+  cxyPrev += dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cx = cxPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -108,11 +123,34 @@ mcsv1_UDAF::ReturnCode regr_intercept::subEvaluate(mcsv1Context* context, const
   struct regr_intercept_data* outData = (struct regr_intercept_data*)context->getUserData()->data;
   struct regr_intercept_data* inData = (struct regr_intercept_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumx2 += inData->sumx2;
-  outData->sumy += inData->sumy;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outCx = outData->cx;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inCx = inData->cx;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+
+  long double resCx = outCx + inCx + deltax * deltax * inCnt * outCnt / resCnt;
+
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->cx = resCx;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -123,18 +161,14 @@ mcsv1_UDAF::ReturnCode regr_intercept::evaluate(mcsv1Context* context, static_an
   long double N = data->cnt;
   if (N > 1)
   {
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumx2 = data->sumx2;
-    long double sumxy = data->sumxy;
+    long double avgx = data->avgx;
+    long double avgy = data->avgy;
+    long double cx = data->cx;
+    long double cxy = data->cxy;
     // regr_intercept is AVG(y) - slope(y,x)*avg(x)
-    // We do some algebra and we can get a slightly smaller calculation
-    long double numerator = sumy * sumx2 - sumx * sumxy;
-    long double var_pop =
-        (N * sumx2) - (sumx * sumx);  // Not realy var_pop, but sort of after some reductions
-    if (var_pop > 0)
+    if (cx > 0)
     {
-      valOut = static_cast<double>(numerator / var_pop);
+      valOut = static_cast<double>(avgy - cxy / cx * avgx);
     }
   }
   return mcsv1_UDAF::SUCCESS;
@@ -146,12 +180,27 @@ mcsv1_UDAF::ReturnCode regr_intercept::dropValue(mcsv1Context* context, ColumnDa
   double valx = toDouble(valsDropped[1]);
   struct regr_intercept_data* data = (struct regr_intercept_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumx -= valx;
-  data->sumx2 -= valx * valx;
-
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev -= dy / cnt;
+  avgxPrev -= dx / cnt;
+
+  cxPrev -= dx * (valx - avgxPrev);
+
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cx = cxPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/regr_r2.cpp b/utils/regr/regr_r2.cpp
index 99a204af8..1a03f895d 100644
--- a/utils/regr/regr_r2.cpp
+++ b/utils/regr/regr_r2.cpp
@@ -39,11 +39,11 @@ static Add_regr_r2_ToUDAFMap addToMap;
 struct regr_r2_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumx2;  // sum of (x squared)
-  long double sumy;
-  long double sumy2;  // sum of (y squared)
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double varx;
+  long double avgy;
+  long double vary;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode regr_r2::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -76,11 +76,11 @@ mcsv1_UDAF::ReturnCode regr_r2::reset(mcsv1Context* context)
 {
   struct regr_r2_data* data = (struct regr_r2_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumx2 = 0.0;
-  data->sumy = 0.0;
-  data->sumy2 = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->varx = 0.0;
+  data->avgy = 0.0;
+  data->vary = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -89,16 +89,30 @@ mcsv1_UDAF::ReturnCode regr_r2::nextValue(mcsv1Context* context, ColumnDatum* va
   double valy = toDouble(valsIn[0]);
   double valx = toDouble(valsIn[1]);
   struct regr_r2_data* data = (struct regr_r2_data*)context->getUserData()->data;
-
-  data->sumy += valy;
-  data->sumy2 += valy * valy;
-
-  data->sumx += valx;
-  data->sumx2 += valx * valx;
-
-  data->sumxy += valx * valy;
-
+  long double avgyPrev = data->avgy;
+  long double varyPrev = data->vary;
+  long double avgxPrev = data->avgx;
+  long double varxPrev = data->varx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev += dy / cnt;
+  avgxPrev += dx / cnt;
+
+  varxPrev += dx * (valx - avgxPrev);
+  varyPrev += dy * (valy - avgyPrev);
+
+  cxyPrev += dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->varx = varxPrev;
+  data->vary = varyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -113,12 +127,38 @@ mcsv1_UDAF::ReturnCode regr_r2::subEvaluate(mcsv1Context* context, const UserDat
   struct regr_r2_data* outData = (struct regr_r2_data*)context->getUserData()->data;
   struct regr_r2_data* inData = (struct regr_r2_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumx2 += inData->sumx2;
-  outData->sumy += inData->sumy;
-  outData->sumy2 += inData->sumy2;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outVarx = outData->varx;
+  long double outVary = outData->vary;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inVarx = inData->varx;
+  long double inVary = inData->vary;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+
+  long double resVarx = outVarx + inVarx + deltax * deltax * inCnt * outCnt / resCnt;
+  long double resVary = outVary + inVary + deltay * deltay * inCnt * outCnt / resCnt;
+
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->varx = resVarx;
+  outData->vary = resVary;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -129,19 +169,17 @@ mcsv1_UDAF::ReturnCode regr_r2::evaluate(mcsv1Context* context, static_any::any&
   double N = data->cnt;
   if (N > 1)
   {
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumx2 = data->sumx2;
-    long double sumy2 = data->sumy2;
-    long double sumxy = data->sumxy;
+    long double varx = data->varx;
+    long double vary = data->vary;
+    long double cxy = data->cxy;
 
-    long double var_popx = (sumx2 - (sumx * sumx / N)) / N;
+    long double var_popx = varx / N;
     if (var_popx <= 0)  // Catch -0
     {
       // When var_popx is 0, NULL is the result.
       return mcsv1_UDAF::SUCCESS;
     }
-    double var_popy = (sumy2 - (sumy * sumy / N)) / N;
+    long double var_popy = vary / N;
     if (var_popy <= 0)  // Catch -0
     {
       // When var_popy is 0, 1 is the result
@@ -150,8 +188,7 @@ mcsv1_UDAF::ReturnCode regr_r2::evaluate(mcsv1Context* context, static_any::any&
     }
     long double std_popx = sqrt(var_popx);
     long double std_popy = sqrt(var_popy);
-    long double covar_pop = (sumxy - ((sumx * sumy) / N)) / N;
-    long double corr = covar_pop / (std_popy * std_popx);
+    long double corr = cxy / (std_popy * std_popx * N);
     valOut = static_cast<double>(corr * corr);
   }
   return mcsv1_UDAF::SUCCESS;
@@ -163,14 +200,30 @@ mcsv1_UDAF::ReturnCode regr_r2::dropValue(mcsv1Context* context, ColumnDatum* va
   double valx = toDouble(valsDropped[1]);
   struct regr_r2_data* data = (struct regr_r2_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumy2 -= valy * valy;
-
-  data->sumx -= valx;
-  data->sumx2 -= valx * valx;
-
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double varyPrev = data->vary;
+  long double avgxPrev = data->avgx;
+  long double varxPrev = data->varx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev -= dy / cnt;
+  avgxPrev -= dx / cnt;
+
+  varxPrev -= dx * (valx - avgxPrev);
+  varyPrev -= dy * (valy - avgyPrev);
+
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->varx = varxPrev;
+  data->vary = varyPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/regr_slope.cpp b/utils/regr/regr_slope.cpp
index de182e148..466bb8687 100644
--- a/utils/regr/regr_slope.cpp
+++ b/utils/regr/regr_slope.cpp
@@ -39,10 +39,10 @@ static Add_regr_slope_ToUDAFMap addToMap;
 struct regr_slope_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumx2;  // sum of (x squared)
-  long double sumy;
-  long double sumxy;  // sum of x * y
+  long double avgx;
+  long double cx;
+  long double avgy;
+  long double cxy;
 };
 
 mcsv1_UDAF::ReturnCode regr_slope::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -74,10 +74,10 @@ mcsv1_UDAF::ReturnCode regr_slope::reset(mcsv1Context* context)
 {
   struct regr_slope_data* data = (struct regr_slope_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumx2 = 0.0;
-  data->sumy = 0.0;
-  data->sumxy = 0.0;
+  data->avgx = 0.0;
+  data->cx = 0.0;
+  data->avgy = 0.0;
+  data->cxy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -87,12 +87,27 @@ mcsv1_UDAF::ReturnCode regr_slope::nextValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsIn[1]);
   struct regr_slope_data* data = (struct regr_slope_data*)context->getUserData()->data;
 
-  data->sumy += valy;
-  data->sumx += valx;
-  data->sumx2 += valx * valx;
-  data->sumxy += valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
+  long double cxyPrev = data->cxy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
 
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev += dy / cnt;
+  avgxPrev += dx / cnt;
+
+  cxPrev += dx * (valx - avgxPrev);
+
+  cxyPrev += dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cx = cxPrev;
+  data->cxy = cxyPrev;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -106,11 +121,35 @@ mcsv1_UDAF::ReturnCode regr_slope::subEvaluate(mcsv1Context* context, const User
   struct regr_slope_data* outData = (struct regr_slope_data*)context->getUserData()->data;
   struct regr_slope_data* inData = (struct regr_slope_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumx2 += inData->sumx2;
-  outData->sumy += inData->sumy;
-  outData->sumxy += inData->sumxy;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outAvgy = outData->avgy;
+  long double outCx = outData->cx;
+  long double outCxy = outData->cxy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inAvgy = inData->avgy;
+  long double inCx = inData->cx;
+  long double inCxy = inData->cxy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+  long double deltay = outAvgy - inAvgy;
+
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+
+  long double resCx = outCx + inCx + deltax * deltax * inCnt * outCnt / resCnt;
+
+  long double resCxy = outCxy + inCxy + deltax * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->avgy = resAvgy;
+  outData->cx = resCx;
+  outData->cxy = resCxy;
+  outData->cnt = resCnt;
+
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -122,18 +161,11 @@ mcsv1_UDAF::ReturnCode regr_slope::evaluate(mcsv1Context* context, static_any::a
   if (N > 1)
   {
     // COVAR_POP(y, x) / VAR_POP(x)
-    long double sumx = data->sumx;
-    long double sumy = data->sumy;
-    long double sumx2 = data->sumx2;
-    long double sumxy = data->sumxy;
-    // These aren't really covar_pop and var_pop. For the purposes of this calculation
-    // we multiplied everything by N to reduce calc time and variance.
-    // It all comes out after the final divide
-    long double covar_pop = N * sumxy - sumx * sumy;
-    long double var_pop = N * sumx2 - sumx * sumx;
-    if (var_pop > 0)
+    long double cx = data->cx;
+    long double cxy = data->cxy;
+    if (cx > 0)
     {
-      valOut = static_cast<double>(covar_pop / var_pop);
+      valOut = static_cast<double>(cxy / cx);
     }
   }
   return mcsv1_UDAF::SUCCESS;
@@ -145,11 +177,27 @@ mcsv1_UDAF::ReturnCode regr_slope::dropValue(mcsv1Context* context, ColumnDatum*
   double valx = toDouble(valsDropped[1]);
   struct regr_slope_data* data = (struct regr_slope_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumx -= valx;
-  data->sumx2 -= valx * valx;
-  data->sumxy -= valx * valy;
+  long double avgyPrev = data->avgy;
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
+  long double cxyPrev = data->cxy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+
+  long double dx = valx - avgxPrev;
+  long double dy = valy - avgyPrev;
+
+  avgyPrev -= dy / cnt;
+  avgxPrev -= dx / cnt;
+
+  cxPrev -= dx * (valx - avgxPrev);
+
+  cxyPrev -= dx * (valy - avgyPrev);
+
+  data->avgx = avgxPrev;
+  data->avgy = avgyPrev;
+  data->cx = cxPrev;
+  data->cxy = cxyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/regr_sxx.cpp b/utils/regr/regr_sxx.cpp
index f62595a6b..b70755652 100644
--- a/utils/regr/regr_sxx.cpp
+++ b/utils/regr/regr_sxx.cpp
@@ -39,8 +39,8 @@ static Add_regr_sxx_ToUDAFMap addToMap;
 struct regr_sxx_data
 {
   uint64_t cnt;
-  long double sumx;
-  long double sumx2;  // sum of (x squared)
+  long double avgx;
+  long double cx;
 };
 
 mcsv1_UDAF::ReturnCode regr_sxx::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -73,8 +73,8 @@ mcsv1_UDAF::ReturnCode regr_sxx::reset(mcsv1Context* context)
 {
   struct regr_sxx_data* data = (struct regr_sxx_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumx = 0.0;
-  data->sumx2 = 0.0;
+  data->avgx = 0.0;
+  data->cx = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -82,11 +82,15 @@ mcsv1_UDAF::ReturnCode regr_sxx::nextValue(mcsv1Context* context, ColumnDatum* v
 {
   double valx = toDouble(valsIn[1]);
   struct regr_sxx_data* data = (struct regr_sxx_data*)context->getUserData()->data;
-
-  data->sumx += valx;
-  data->sumx2 += valx * valx;
-
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
+  avgxPrev += dx / cnt;
+  cxPrev += dx * (valx - avgxPrev);
+  data->avgx = avgxPrev;
+  data->cx = cxPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -101,9 +105,24 @@ mcsv1_UDAF::ReturnCode regr_sxx::subEvaluate(mcsv1Context* context, const UserDa
   struct regr_sxx_data* outData = (struct regr_sxx_data*)context->getUserData()->data;
   struct regr_sxx_data* inData = (struct regr_sxx_data*)userDataIn->data;
 
-  outData->sumx += inData->sumx;
-  outData->sumx2 += inData->sumx2;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgx = outData->avgx;
+  long double outCx = outData->cx;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgx = inData->avgx;
+  long double inCx = inData->cx;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltax = outAvgx - inAvgx;
+
+  long double resAvgx = inAvgx + deltax * outCnt / resCnt;
+
+  long double resCx = outCx + inCx + deltax * deltax * inCnt * outCnt / resCnt;
+
+  outData->avgx = resAvgx;
+  outData->cx = resCx;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -114,7 +133,7 @@ mcsv1_UDAF::ReturnCode regr_sxx::evaluate(mcsv1Context* context, static_any::any
   long double N = data->cnt;
   if (N > 0)
   {
-    long double regr_sxx = (data->sumx2 - (data->sumx * data->sumx / N));
+    long double regr_sxx = data->cx;
     if (regr_sxx < 0)  // catch -0
       regr_sxx = 0;
     valOut = static_cast<double>(regr_sxx);
@@ -126,11 +145,15 @@ mcsv1_UDAF::ReturnCode regr_sxx::dropValue(mcsv1Context* context, ColumnDatum* v
 {
   double valx = toDouble(valsDropped[1]);
   struct regr_sxx_data* data = (struct regr_sxx_data*)context->getUserData()->data;
-
-  data->sumx -= valx;
-  data->sumx2 -= valx * valx;
-
+  long double avgxPrev = data->avgx;
+  long double cxPrev = data->cx;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dx = valx - avgxPrev;
+  avgxPrev -= dx / cnt;
+  cxPrev -= dx * (valx - avgxPrev);
+  data->avgx = avgxPrev;
+  data->cx = cxPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
diff --git a/utils/regr/regr_syy.cpp b/utils/regr/regr_syy.cpp
index 2b39fea5d..350c8605b 100644
--- a/utils/regr/regr_syy.cpp
+++ b/utils/regr/regr_syy.cpp
@@ -39,8 +39,8 @@ static Add_regr_syy_ToUDAFMap addToMap;
 struct regr_syy_data
 {
   uint64_t cnt;
-  long double sumy;
-  long double sumy2;  // sum of (y squared)
+  long double avgy;
+  long double cy;  // sum of (y squared)
 };
 
 mcsv1_UDAF::ReturnCode regr_syy::init(mcsv1Context* context, ColumnDatum* colTypes)
@@ -73,8 +73,8 @@ mcsv1_UDAF::ReturnCode regr_syy::reset(mcsv1Context* context)
 {
   struct regr_syy_data* data = (struct regr_syy_data*)context->getUserData()->data;
   data->cnt = 0;
-  data->sumy = 0.0;
-  data->sumy2 = 0.0;
+  data->avgy = 0.0;
+  data->cy = 0.0;
   return mcsv1_UDAF::SUCCESS;
 }
 
@@ -82,11 +82,15 @@ mcsv1_UDAF::ReturnCode regr_syy::nextValue(mcsv1Context* context, ColumnDatum* v
 {
   double valy = toDouble(valsIn[0]);
   struct regr_syy_data* data = (struct regr_syy_data*)context->getUserData()->data;
-
-  data->sumy += valy;
-  data->sumy2 += valy * valy;
-
+  long double avgyPrev = data->avgy;
+  long double cyPrev = data->cy;
   ++data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dy = valy - avgyPrev;
+  avgyPrev += dy / cnt;
+  cyPrev += dy * (valy - avgyPrev);
+  data->avgy = avgyPrev;
+  data->cy = cyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -101,9 +105,24 @@ mcsv1_UDAF::ReturnCode regr_syy::subEvaluate(mcsv1Context* context, const UserDa
   struct regr_syy_data* outData = (struct regr_syy_data*)context->getUserData()->data;
   struct regr_syy_data* inData = (struct regr_syy_data*)userDataIn->data;
 
-  outData->sumy += inData->sumy;
-  outData->sumy2 += inData->sumy2;
-  outData->cnt += inData->cnt;
+  uint64_t outCnt = outData->cnt;
+  long double outAvgy = outData->avgy;
+  long double outCy = outData->cy;
+
+  uint64_t inCnt = inData->cnt;
+  long double inAvgy = inData->avgy;
+  long double inCy = inData->cy;
+
+  uint64_t resCnt = inCnt + outCnt;
+  long double deltay = outAvgy - inAvgy;
+
+  long double resAvgy = inAvgy + deltay * outCnt / resCnt;
+
+  long double resCy = outCy + inCy + deltay * deltay * inCnt * outCnt / resCnt;
+
+  outData->avgy = resAvgy;
+  outData->cy = resCy;
+  outData->cnt = resCnt;
 
   return mcsv1_UDAF::SUCCESS;
 }
@@ -114,7 +133,7 @@ mcsv1_UDAF::ReturnCode regr_syy::evaluate(mcsv1Context* context, static_any::any
   long double N = data->cnt;
   if (N > 0)
   {
-    long double var_popy = (data->sumy2 - (data->sumy * data->sumy / N));
+    long double var_popy = data->cy;
     if (var_popy < 0)  // might be -0
       var_popy = 0;
     valOut = static_cast<double>(var_popy);
@@ -127,10 +146,15 @@ mcsv1_UDAF::ReturnCode regr_syy::dropValue(mcsv1Context* context, ColumnDatum* v
   double valy = toDouble(valsDropped[0]);
   struct regr_syy_data* data = (struct regr_syy_data*)context->getUserData()->data;
 
-  data->sumy -= valy;
-  data->sumy2 -= valy * valy;
-
+  long double avgyPrev = data->avgy;
+  long double cyPrev = data->cy;
   --data->cnt;
+  uint64_t cnt = data->cnt;
+  long double dy = valy - avgyPrev;
+  avgyPrev -= dy / cnt;
+  cyPrev -= dy * (valy - avgyPrev);
+  data->avgy = avgyPrev;
+  data->cy = cyPrev;
 
   return mcsv1_UDAF::SUCCESS;
 }