PL/Python uses str(v) to convert float data, but is lossy by design. Only repr(v) is guaranteed to have enough precision to make floats roundtrip properly:
https://docs.python.org/2/library/functions.html#func-repr https://docs.python.org/2/library/functions.html#str Example: $ python >>> repr(100100100.654321) '100100100.654321' >>> str(100100100.654321) '100100100.654' Attached patch uses PyObject_Repr() for float data. As it's annoying-to-debug problem and the patch is simple, perhaps it's worth backporting? -- marko
diff --git a/src/pl/plpython/expected/plpython_types.out b/src/pl/plpython/expected/plpython_types.out index 61d800b..17057a5 100644 --- a/src/pl/plpython/expected/plpython_types.out +++ b/src/pl/plpython/expected/plpython_types.out @@ -354,6 +354,14 @@ CONTEXT: PL/Python function "test_type_conversion_float8" (1 row) +SELECT * FROM test_type_conversion_float8(100100100.654321); +INFO: (100100100.654321, <type 'float'>) +CONTEXT: PL/Python function "test_type_conversion_float8" + test_type_conversion_float8 +----------------------------- + 100100100.654321 +(1 row) + CREATE FUNCTION test_type_conversion_oid(x oid) RETURNS oid AS $$ plpy.info(x, type(x)) return x diff --git a/src/pl/plpython/plpy_typeio.c b/src/pl/plpython/plpy_typeio.c index 524534e..8c70c7c 100644 --- a/src/pl/plpython/plpy_typeio.c +++ b/src/pl/plpython/plpy_typeio.c @@ -760,6 +760,18 @@ PLyObject_ToDatum(PLyObToDatum *arg, int32 typmod, PyObject *plrv) if (PyUnicode_Check(plrv)) plrv_bo = PLyUnicode_Bytes(plrv); + else if (PyFloat_Check(plrv)) + { + /* use repr() for floats, str() is lossy */ +#if PY_MAJOR_VERSION >= 3 + PyObject *s = PyObject_Repr(plrv); + + plrv_bo = PLyUnicode_Bytes(s); + Py_XDECREF(s); +#else + plrv_bo = PyObject_Repr(plrv); +#endif + } else { #if PY_MAJOR_VERSION >= 3 diff --git a/src/pl/plpython/sql/plpython_types.sql b/src/pl/plpython/sql/plpython_types.sql index d9d0db6..19d920d 100644 --- a/src/pl/plpython/sql/plpython_types.sql +++ b/src/pl/plpython/sql/plpython_types.sql @@ -122,6 +122,7 @@ SELECT * FROM test_type_conversion_float8(100); SELECT * FROM test_type_conversion_float8(-100); SELECT * FROM test_type_conversion_float8(5000000000.5); SELECT * FROM test_type_conversion_float8(null); +SELECT * FROM test_type_conversion_float8(100100100.654321); CREATE FUNCTION test_type_conversion_oid(x oid) RETURNS oid AS $$
-- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers