fix float or double value directly tested for equality #1041 (#1066)

* fix float or double value directly tested for equality

* fix problem

src/sql/engine/expr/ob_expr_div.cpp

@@ -23,6 +23,8 @@ using namespace common;
 using namespace share;
 using namespace common::number;
 
+constexpr double EPSILON = 0.000000001;
+
 ObExprDiv::ObExprDiv(ObIAllocator& alloc, ObExprOperatorType type)
     : ObArithExprOperator(alloc, type, N_DIV, 2, NOT_ROW_DIMENSION, ObExprResultTypeUtil::get_div_result_type,
           ObExprResultTypeUtil::get_div_calc_type, div_funcs_)
@@ -219,7 +221,7 @@ int ObExprDiv::div_float(ObObj& res, const ObObj& left, const ObObj& right, ObIA
   } else if (OB_UNLIKELY(left.get_type_class() != right.get_type_class())) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("Invalid types", K(ret), K(left), K(right));
-  } else if (fabsf(right.get_float()) == 0.0) {
+  } else if (fabsf(right.get_float()) < EPSILON) {
     ret = OB_ERR_DIVISOR_IS_ZERO;
     LOG_WARN("division by zero not allowed now", K(res), K(left), K(right));
   } else {
@@ -246,7 +248,7 @@ int ObExprDiv::div_double(ObObj& res, const ObObj& left, const ObObj& right, ObI
   if (OB_UNLIKELY(left.get_type_class() != right.get_type_class())) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("Invalid types", K(ret), K(left), K(right));
-  } else if (fabs(right.get_double()) == 0.0) {
+  } else if (fabs(right.get_double()) < EPSILON) {
     if (is_oracle_mode()) {
       ret = OB_ERR_DIVISOR_IS_ZERO;
       LOG_WARN("division by zero not allowed now", K(res), K(left), K(right));
@@ -278,7 +280,7 @@ int ObExprDiv::div_double_no_overflow(ObObj& res, const ObObj& left, const ObObj
   if (OB_UNLIKELY(left.get_type_class() != right.get_type_class())) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("Invalid types", K(ret), K(left), K(right));
-  } else if (lib::is_mysql_mode() && (fabs(right.get_double()) == 0.0)) {
+  } else if (lib::is_mysql_mode() && (fabs(right.get_double()) < EPSILON)) {
     res.set_null();
   } else {
     res.set_double(left.get_double() / right.get_double());
@@ -440,7 +442,7 @@ int ObExprDiv::div_double(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& datum)
   } else {
     const double left_d = left->get_double();
     const double right_d = right->get_double();
-    if (is_mysql_mode() && (fabs(right_d) == 0.0)) {
+    if (is_mysql_mode() && (fabs(right_d) < EPSILON)) {
       datum.set_null();
     } else {
       const double result_d = left_d / right_d;
@@ -643,7 +645,7 @@ int ObExprDiv::div_float(ObDatum& result, const ObDatum& left, const ObDatum& ri
   UNUSED(ctx);
   const float left_f = left.get_float();
   const float right_f = right.get_float();
-  if (fabsf(right_f) == 0.0) {
+  if (fabsf(right_f) < EPSILON) {
     ret = OB_ERR_DIVISOR_IS_ZERO;
     LOG_WARN("division by zero not allowed now", K(ret), K(right_f));
   } else {

src/sql/engine/expr/ob_expr_mod.cpp

@@ -214,7 +214,7 @@ int ObExprMod::mod_double(ObObj& res, const ObObj& left, const ObObj& right, ObI
   if (OB_UNLIKELY(left.get_type_class() != right.get_type_class())) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("Invalid types", K(ret), K(left), K(right));
-  } else if (fabs(right.get_double()) == 0.0) {
+  } else if (fabs(right.get_double()) < EPSILON) {
     if (lib::is_oracle_mode()) {
       res.set_double(left.get_double());
     } else {

src/sql/optimizer/ob_opt_est_sel.cpp

@@ -35,6 +35,7 @@ using namespace oceanbase::share::schema;
 namespace oceanbase {
 namespace sql {
 double ObOptEstSel::DEFAULT_COLUMN_DISTINCT_RATIO = EST_DEF_COL_NUM_DISTINCT * 1.0 / OB_EST_DEFAULT_ROW_COUNT;
+constexpr double EPSILON = 0.000000001;
 
 int ObOptEstSel::calculate_selectivity(const ObEstSelInfo& est_sel_info, const ObIArray<ObRawExpr*>& quals,
     double& selectivity, ObIArray<ObExprSelPair>* all_predicate_sel, ObJoinType join_type, const ObRelIds* left_rel_ids,
@@ -3118,7 +3119,7 @@ int ObOptEstSel::get_agg_sel(const ObEstSelInfo& est_sel_info, const ObRawExpr&
       }
     } else if (T_FUN_SUM == aggr_expr->get_expr_type() || T_FUN_AVG == aggr_expr->get_expr_type()) {
       LOG_TRACE("show group by origen rows and grouped rows", K(origen_rows), K(grouped_rows));
-      double rows_per_group = grouped_rows == 0.0 ? origen_rows : origen_rows / grouped_rows;
+      double rows_per_group = fabs(grouped_rows) < EPSILON ? origen_rows : origen_rows / grouped_rows;
       if (OB_FAIL(get_agg_sel_with_minmax(
               est_sel_info, *aggr_expr, const_expr1, const_expr2, type, selectivity, rows_per_group))) {
         LOG_WARN("failed to get agg sel with minmax", K(ret));