Improved support for planned database maintenance by internally sending

explicit request boundaries when using python-oracledb connection pools.

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -27,6 +27,8 @@ Thin Mode Changes
 #)  Added parameter :data:`ConnectParams.use_sni` to specify that the TLS SNI
     extension should be used to reduce the number of TLS neegotiations that are
     needed to connect to the database.
+#)  Improved support for planned database maintenance by internally sending
+    explicit request boundaries when using python-oracledb connection pools.
 #)  Added parameter :data:`ConnectParams.instance_name` to specify the instance
     name to use when connecting to the database. Added support for setting the
     instance name in :ref:`Easy Connect strings <easyconnect>`.

src/oracledb/base_impl.pxd

@@ -616,6 +616,7 @@ cdef class BaseConnImpl:
         readonly bint supports_bool
         ssize_t _oson_max_fname_size
         bint _allow_bind_str_to_lob
+        bint _in_request
 
     cdef object _check_value(self, OracleMetadata type_info, object value,
                              bint* is_ok)

src/oracledb/impl/thin/capabilities.pyx

@@ -126,7 +126,8 @@ cdef class Capabilities:
         self.compile_caps[TNS_CCAP_TTC2] = TNS_CCAP_ZLNP
         self.compile_caps[TNS_CCAP_OCI2] = TNS_CCAP_DRCP
         self.compile_caps[TNS_CCAP_CLIENT_FN] = TNS_CCAP_CLIENT_FN_MAX
-        self.compile_caps[TNS_CCAP_TTC4] = TNS_CCAP_INBAND_NOTIFICATION
+        self.compile_caps[TNS_CCAP_TTC4] = TNS_CCAP_INBAND_NOTIFICATION | \
+                TNS_CCAP_EXPLICIT_BOUNDARY
         self.compile_caps[TNS_CCAP_TTC5] = TNS_CCAP_VECTOR_SUPPORT | \
                 TNS_CCAP_TOKEN_SUPPORTED | TNS_CCAP_PIPELINING_SUPPORT | \
                 TNS_CCAP_PIPELINING_BREAK

src/oracledb/impl/thin/connection.pyx

@@ -73,6 +73,7 @@ cdef class BaseThinConnImpl(BaseConnImpl):
         bint _is_pool_extra
         bytes _transaction_context
         uint8_t pipeline_mode
+        uint8_t _session_state_desired
 
     def __init__(self, str dsn, ConnectParamsImpl params):
         if not HAS_CRYPTOGRAPHY:

src/oracledb/impl/thin/constants.pxi

@@ -296,6 +296,7 @@ cdef enum:
     TNS_FUNC_REEXECUTE_AND_FETCH = 78
     TNS_FUNC_SESSION_GET = 162
     TNS_FUNC_SESSION_RELEASE = 163
+    TNS_FUNC_SESSION_STATE = 176
     TNS_FUNC_SET_SCHEMA = 152
     TNS_FUNC_TPC_TXN_SWITCH = 103
     TNS_FUNC_TPC_TXN_CHANGE_STATE = 104
@@ -399,6 +400,7 @@ cdef enum:
     TNS_CCAP_DRCP = 0x10
     TNS_CCAP_ZLNP = 0x04
     TNS_CCAP_INBAND_NOTIFICATION = 0x04
+    TNS_CCAP_EXPLICIT_BOUNDARY = 0x40
     TNS_CCAP_END_OF_RESPONSE = 0x20
     TNS_CCAP_CLIENT_FN_MAX = 12
     TNS_CCAP_VECTOR_SUPPORT = 0x08
@@ -468,6 +470,12 @@ cdef enum:
     TNS_PIPELINE_MODE_CONTINUE_ON_ERROR = 1
     TNS_PIPELINE_MODE_ABORT_ON_ERROR = 2
 
+# session state flags
+cdef enum:
+    TNS_SESSION_STATE_REQUEST_BEGIN = 0x04
+    TNS_SESSION_STATE_REQUEST_END = 0x08
+    TNS_SESSION_STATE_EXPLICIT_BOUNDARY = 0x40
+
 # other constants
 cdef enum:
     TNS_ESCAPE_CHAR = 253