Optimize numeric conversions in jsonb_plpython

Author: Nikita Glukhov

contrib/jsonb_plpython/jsonb_plpython.c

@@ -126,6 +126,13 @@ PLyObject_FromJsonbValue(JsonbValue *jsonbValue)
 			{
 				Datum		num;
 				char	   *str;
+				int64		intval;
+
+				if (numeric_to_exact_int64(jsonbValue->val.numeric, &intval))
+#ifndef HAVE_LONG_INT_64
+					if ((long) intval == intval)
+#endif
+						return PyInt_FromLong((long) intval);
 
 				num = NumericGetDatum(jsonbValue->val.numeric);
 				str = DatumGetCString(DirectFunctionCall1(numeric_out, num));
@@ -409,7 +416,26 @@ static JsonbValue *
 PLyNumber_ToJsonbValue(PyObject *obj, JsonbValue *jbvNum)
 {
 	Numeric		num;
-	char	   *str = PLyObject_AsString(obj);
+	char	   *str;
+
+	jbvNum->type = jbvNumeric;
+
+	if (PyInt_Check(obj))
+	{
+		long		val = PyInt_AsLong(obj);
+
+		if (val != -1 || !PyErr_Occurred())
+		{
+			jbvNum->val.numeric =
+				DatumGetNumeric(DirectFunctionCall1(int8_numeric,
+													Int64GetDatum((int64) val)));
+			return jbvNum;
+		}
+
+		PyErr_Clear();
+	}
+
+	str = PLyObject_AsString(obj);
 
 	PG_TRY();
 	{
@@ -441,7 +467,6 @@ PLyNumber_ToJsonbValue(PyObject *obj, JsonbValue *jbvNum)
 				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
 				 (errmsg("cannot convert NaN to jsonb"))));
 
-	jbvNum->type = jbvNumeric;
 	jbvNum->val.numeric = num;
 
 	return jbvNum;

src/backend/utils/adt/numeric.c

@@ -3349,6 +3349,27 @@ numeric_float4(PG_FUNCTION_ARGS)
 	PG_RETURN_DATUM(result);
 }
 
+/*
+ * numeric_get_int64() -
+ *
+ *	Try to convert numeric to int64 if it is an exact integer (i.e. it does
+ *	not have digits after the decimal point).  Return true if okay.
+ */
+bool
+numeric_to_exact_int64(Numeric num, int64 *result)
+{
+	NumericVar	var;
+
+	if (NUMERIC_IS_NAN(num))
+		return false;
+
+	if (NUMERIC_DSCALE(num) != 0)
+		return false;	/* digits after the decimal point are not allowed */
+
+	init_var_from_num(num, &var);
+
+	return numericvar_to_int64(&var, result);
+}
 
 /* ----------------------------------------------------------------------
  *

src/include/utils/numeric.h

@@ -60,5 +60,6 @@ extern bool numeric_is_nan(Numeric num);
 int32		numeric_maximum_size(int32 typmod);
 extern char *numeric_out_sci(Numeric num, int scale);
 extern char *numeric_normalize(Numeric num);
+extern bool numeric_to_exact_int64(Numeric value, int64 *out);
 
 #endif							/* _PG_NUMERIC_H_ */