diff --git a/doc/src/sgml/plpython.sgml b/doc/src/sgml/plpython.sgml
index aaf758d..da27874 100644
--- a/doc/src/sgml/plpython.sgml
+++ b/doc/src/sgml/plpython.sgml
@@ -308,14 +308,19 @@ $$ LANGUAGE plpythonu;
+
+
+ PostgreSQL real and double are converted to
+ Python float.
+
+
+
- PostgreSQL real, double,
- and numeric are converted to
- Python float. Note that for
- the numeric this loses information and can lead to
- incorrect results. This might be fixed in a future
- release.
+ PostgreSQL numeric is converted to
+ Python Decimal. This type is imported from
+ cdecimal package if it is available. If cdecimal
+ cannot be used, then decimal.Decimal will be used.
diff --git a/src/pl/plpython/expected/plpython_types.out b/src/pl/plpython/expected/plpython_types.out
index 4641345..1742114 100644
--- a/src/pl/plpython/expected/plpython_types.out
+++ b/src/pl/plpython/expected/plpython_types.out
@@ -213,36 +213,52 @@ CONTEXT: PL/Python function "test_type_conversion_int8"
(1 row)
CREATE FUNCTION test_type_conversion_numeric(x numeric) RETURNS numeric AS $$
-plpy.info(x, type(x))
+plpy.info(x.__class__.__name__)
return x
$$ LANGUAGE plpythonu;
-/* The current implementation converts numeric to float. */
+/* The current implementation converts numeric to Decimal. */
SELECT * FROM test_type_conversion_numeric(100);
-INFO: (100.0, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
- 100.0
+ 100
(1 row)
SELECT * FROM test_type_conversion_numeric(-100);
-INFO: (-100.0, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
- -100.0
+ -100
(1 row)
SELECT * FROM test_type_conversion_numeric(5000000000.5);
-INFO: (5000000000.5, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
5000000000.5
(1 row)
+SELECT * FROM test_type_conversion_numeric(1234567890.0987654321);
+INFO: Decimal
+CONTEXT: PL/Python function "test_type_conversion_numeric"
+ test_type_conversion_numeric
+------------------------------
+ 1234567890.0987654321
+(1 row)
+
+SELECT * FROM test_type_conversion_numeric(-1234567890.0987654321);
+INFO: Decimal
+CONTEXT: PL/Python function "test_type_conversion_numeric"
+ test_type_conversion_numeric
+------------------------------
+ -1234567890.0987654321
+(1 row)
+
SELECT * FROM test_type_conversion_numeric(null);
-INFO: (None, )
+INFO: NoneType
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
diff --git a/src/pl/plpython/expected/plpython_types_3.out b/src/pl/plpython/expected/plpython_types_3.out
index 511ef5a..57538b3 100644
--- a/src/pl/plpython/expected/plpython_types_3.out
+++ b/src/pl/plpython/expected/plpython_types_3.out
@@ -213,36 +213,52 @@ CONTEXT: PL/Python function "test_type_conversion_int8"
(1 row)
CREATE FUNCTION test_type_conversion_numeric(x numeric) RETURNS numeric AS $$
-plpy.info(x, type(x))
+plpy.info(str(x))
return x
$$ LANGUAGE plpython3u;
-/* The current implementation converts numeric to float. */
+/* The current implementation converts numeric to Decimal. */
SELECT * FROM test_type_conversion_numeric(100);
-INFO: (100.0, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
- 100.0
+ 100
(1 row)
SELECT * FROM test_type_conversion_numeric(-100);
-INFO: (-100.0, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
- -100.0
+ -100
(1 row)
SELECT * FROM test_type_conversion_numeric(5000000000.5);
-INFO: (5000000000.5, )
+INFO: Decimal
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
5000000000.5
(1 row)
+SELECT * FROM test_type_conversion_numeric(1234567890.0987654321);
+INFO: Decimal
+CONTEXT: PL/Python function "test_type_conversion_numeric"
+ test_type_conversion_numeric
+------------------------------
+ 1234567890.0987654321
+(1 row)
+
+SELECT * FROM test_type_conversion_numeric(-1234567890.0987654321);
+INFO: Decimal
+CONTEXT: PL/Python function "test_type_conversion_numeric"
+ test_type_conversion_numeric
+------------------------------
+ -1234567890.0987654321
+(1 row)
+
SELECT * FROM test_type_conversion_numeric(null);
-INFO: (None, )
+INFO: NoneType
CONTEXT: PL/Python function "test_type_conversion_numeric"
test_type_conversion_numeric
------------------------------
diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c
index 6a9a2cb..e04c2f9 100644
--- a/src/pl/plpython/plpy_typeio.c
+++ b/src/pl/plpython/plpy_typeio.c
@@ -18,6 +18,7 @@
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/typcache.h"
+#include "utils/numeric.h"
#include "plpython.h"
@@ -35,7 +36,7 @@ static void PLy_output_datum_func2(PLyObToDatum *arg, HeapTuple typeTup);
static PyObject *PLyBool_FromBool(PLyDatumToOb *arg, Datum d);
static PyObject *PLyFloat_FromFloat4(PLyDatumToOb *arg, Datum d);
static PyObject *PLyFloat_FromFloat8(PLyDatumToOb *arg, Datum d);
-static PyObject *PLyFloat_FromNumeric(PLyDatumToOb *arg, Datum d);
+static PyObject *PLyDecimal_FromNumeric(PLyDatumToOb *arg, Datum d);
static PyObject *PLyInt_FromInt16(PLyDatumToOb *arg, Datum d);
static PyObject *PLyInt_FromInt32(PLyDatumToOb *arg, Datum d);
static PyObject *PLyLong_FromInt64(PLyDatumToOb *arg, Datum d);
@@ -450,7 +451,7 @@ PLy_input_datum_func2(PLyDatumToOb *arg, Oid typeOid, HeapTuple typeTup)
arg->func = PLyFloat_FromFloat8;
break;
case NUMERICOID:
- arg->func = PLyFloat_FromNumeric;
+ arg->func = PLyDecimal_FromNumeric;
break;
case INT2OID:
arg->func = PLyInt_FromInt16;
@@ -516,16 +517,33 @@ PLyFloat_FromFloat8(PLyDatumToOb *arg, Datum d)
}
static PyObject *
-PLyFloat_FromNumeric(PLyDatumToOb *arg, Datum d)
+PLyDecimal_FromNumeric(PLyDatumToOb *arg, Datum d)
{
- /*
- * Numeric is cast to a PyFloat: This results in a loss of precision Would
- * it be better to cast to PyString?
- */
- Datum f = DirectFunctionCall1(numeric_float8, d);
- double x = DatumGetFloat8(f);
+ char *x;
+ PyObject *pvalue, *value, *decimal, *decimal_dict;
+ static PyObject *decimal_ctor;
+
+ /* Try to import cdecimal, if it doesnt exist, fallback to decimal */
+ if (decimal_ctor == NULL)
+ {
+ decimal = PyImport_ImportModule("cdecimal");
+ if (decimal == NULL)
+ {
+ PyErr_Clear();
+ decimal = PyImport_ImportModule("decimal");
+ }
+ if (decimal == NULL)
+ PLy_elog(ERROR, "could not import module 'decimal'");
+
+ decimal_dict = PyModule_GetDict(decimal);
+ decimal_ctor = PyDict_GetItemString(decimal_dict, "Decimal");
+ Py_DECREF(decimal_dict);
+ }
- return PyFloat_FromDouble(x);
+ x = DatumGetCString(DirectFunctionCall1(numeric_out, d));
+ pvalue = PyString_FromString(x);
+ value = PyObject_CallFunctionObjArgs(decimal_ctor, pvalue, NULL);
+ return value;
}
static PyObject *
diff --git a/src/pl/plpython/sql/plpython_types.sql b/src/pl/plpython/sql/plpython_types.sql
index 6a50b42..fd7fbca 100644
--- a/src/pl/plpython/sql/plpython_types.sql
+++ b/src/pl/plpython/sql/plpython_types.sql
@@ -86,14 +86,16 @@ SELECT * FROM test_type_conversion_int8(null);
CREATE FUNCTION test_type_conversion_numeric(x numeric) RETURNS numeric AS $$
-plpy.info(x, type(x))
+plpy.info(x.__class__.__name__)
return x
$$ LANGUAGE plpythonu;
-/* The current implementation converts numeric to float. */
+/* The current implementation converts numeric to Decimal. */
SELECT * FROM test_type_conversion_numeric(100);
SELECT * FROM test_type_conversion_numeric(-100);
SELECT * FROM test_type_conversion_numeric(5000000000.5);
+SELECT * FROM test_type_conversion_numeric(1234567890.0987654321);
+SELECT * FROM test_type_conversion_numeric(-1234567890.0987654321);
SELECT * FROM test_type_conversion_numeric(null);