Ensure that max >= min when creating pools.

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -50,6 +50,13 @@ Common Changes
     (`PR 496 <https://github.com/oracle/python-oracledb/pull/496>`__).
 #)  Fix bug with GitHub build action merge artifacts step
     (`issue 495 <https://github.com/oracle/python-oracledb/issues/495>`__).
+#)  Error ``DPY-2064: parameter 'max' should be greater than or equal to
+    parameter 'min'`` is now raised when a call to
+    :meth:`oracledb.create_pool()`, :meth:`oracledb.create_pool_async()`
+    or :meth:`oracledb.PoolParams()` is made with parameter "max" less than the
+    parameter "min". Previously python-oracledb Thin mode did not raise an
+    error and python-oracledb Thick mode raised the exception
+    ``ORA-24413: Invalid number of sessions specified``.
 #)  Improved the test suite and documentation.
 
 

src/oracledb/errors.py

@@ -287,6 +287,7 @@ def _raise_not_supported(feature: str) -> None:
 ERR_PARAMS_HOOK_HANDLER_FAILED = 2061
 ERR_PAYLOAD_CANNOT_BE_ENQUEUED = 2062
 ERR_SCROLL_OUT_OF_RESULT_SET = 2063
+ERR_POOL_MAX_LESS_THAN_MIN = 2064
 
 # error numbers that result in NotSupportedError
 ERR_TIME_NOT_SUPPORTED = 3000
@@ -781,6 +782,9 @@ def _raise_not_supported(feature: str) -> None:
     ERR_POOL_HAS_BUSY_CONNECTIONS: (
         "connection pool cannot be closed because connections are busy"
     ),
+    ERR_POOL_MAX_LESS_THAN_MIN: (
+        "parameter 'max' should be greater than or equal to parameter 'min'"
+    ),
     ERR_POOL_NO_CONNECTION_AVAILABLE: (
         "timed out waiting for the connection pool to return a connection"
     ),

src/oracledb/impl/base/pool_params.pyx

@@ -94,6 +94,10 @@ cdef class PoolParamsImpl(ConnectParamsImpl):
         _set_int_param(args, "ping_interval", &self.ping_interval)
         _set_uint_param(args, "ping_timeout", &self.ping_timeout)
 
+        # verify that max >= min
+        if self.max < self.min:
+            errors._raise_err(errors.ERR_POOL_MAX_LESS_THAN_MIN)
+
         # if the pool is dynamically sized (min != max) then ensure that the
         # increment value is non-zero (as otherwise the pool would never grow!)
         if self.max != self.min and self.increment == 0:

tests/test_2400_pool.py

@@ -1079,6 +1079,11 @@ def hook(params):
             self.assertEqual(conn.stmtcachesize, orig_stmtcachesize)
         pool.close()
 
+    def test_2456(self):
+        "2456 - test creation of pool with min > max"
+        with self.assertRaisesFullCode("DPY-2064"):
+            test_env.get_pool(min=3, max=2)
+
 
 if __name__ == "__main__":
     test_env.run_test_cases()

tests/test_4700_pool_params.py

@@ -35,12 +35,13 @@
 class TestCase(test_env.BaseTestCase):
     requires_connection = False
 
-    def __test_writable_parameter(self, name, value):
+    def __test_writable_parameter(self, name, value, params=None):
         """
         Tests that a writable parameter can be written to and the modified
         value read back successfully.
         """
-        params = oracledb.PoolParams()
+        if params is None:
+            params = oracledb.PoolParams()
         orig_value = getattr(params, name)
         copied_params = params.copy()
         args = {}
@@ -54,7 +55,7 @@ def __test_writable_parameter(self, name, value):
 
     def test_4700(self):
         "4700 - test writable parameters"
-        self.__test_writable_parameter("min", 8)
+        self.__test_writable_parameter("min", 8, oracledb.PoolParams(max=10))
         self.__test_writable_parameter("max", 12)
         self.__test_writable_parameter("increment", 2)
         self.__test_writable_parameter("connectiontype", oracledb.Connection)
@@ -164,6 +165,8 @@ def test_4702(self):
             conn_string = f"{host}/{service_name}?pyo.{name}={str_value}"
             with self.subTest(name=name, value=str_value):
                 params = oracledb.PoolParams()
+                if name == "min" and actual_value > params.max:
+                    params.set(max=actual_value)
                 params.parse_connect_string(conn_string)
                 self.assertEqual(params.host, host)
                 self.assertEqual(params.service_name, service_name)

tests/test_5500_pool_async.py

@@ -630,6 +630,11 @@ async def test_5541(self):
                 with self.assertRaises(TypeError):
                     test_env.get_pool_async(pool_alias=alias)
 
+    async def test_5542(self):
+        "5542 - test creation of pool with min > max"
+        with self.assertRaisesFullCode("DPY-2064"):
+            test_env.get_pool_async(min=3, max=2)
+
 
 if __name__ == "__main__":
     test_env.run_test_cases()