Drop checks for IBM DB2

This hasn't been supported by any project for many years. Quoting from
the nova patch that removed DB2 support [1]

  This removes db2 support from tree completely. This is an oddball non
  open database that made doing live data migrations difficult. It is
  used by 0% of users in the OpenStack User Survey.

  Supporting commercial software that doesn't have users at the cost of
  delivering features and fixes to our community is the wrong tradeoff.
  This corrects that.

There's no need to keep this around.

[1] Ifeb9929e4515e3483eb65d371126afd7672b92a4

Change-Id: I8c3f23083e09e5ac924e35d1b7b3248a0d074e1b
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

7 files changed, 18 insertions, 134 deletions

diff --git a/oslo_db/sqlalchemy/engines.py b/oslo_db/sqlalchemy/engines.py
index 0e19c18..de3719a 100644
--- a/oslo_db/sqlalchemy/engines.py
+++ b/oslo_db/sqlalchemy/engines.py
@@ -69,7 +69,7 @@ def _connect_ping_listener(connection, branch):
     connection.should_close_with_result = False
     try:
         # run a SELECT 1.   use a core select() so that
-        # any details like that needed by Oracle, DB2 etc. are handled.
+        # any details like that needed by the backend are handled.
         connection.scalar(select([1]))
     except exception.DBConnectionError:
         # catch DBConnectionError, which is raised by the filter
diff --git a/oslo_db/sqlalchemy/exc_filters.py b/oslo_db/sqlalchemy/exc_filters.py
index 2b3ce2c..e578987 100644
--- a/oslo_db/sqlalchemy/exc_filters.py
+++ b/oslo_db/sqlalchemy/exc_filters.py
@@ -67,29 +67,25 @@ def filters(dbname, exception_type, regex):
          r"^.*\b1213\b.*Deadlock: wsrep aborted.*")
 @filters("postgresql", sqla_exc.OperationalError, r"^.*deadlock detected.*")
 @filters("postgresql", sqla_exc.DBAPIError, r"^.*deadlock detected.*")
-@filters("ibm_db_sa", sqla_exc.DBAPIError, r"^.*SQL0911N.*")
 def _deadlock_error(operational_error, match, engine_name, is_disconnect):
     """Filter for MySQL or Postgresql deadlock error.
 
     NOTE(comstud): In current versions of DB backends, Deadlock violation
     messages follow the structure:
 
-    mysql+mysqldb:
-    (OperationalError) (1213, 'Deadlock found when trying to get lock; try '
-                         'restarting transaction') <query_str> <query_args>
+    mysql+mysqldb::
 
-    mysql+mysqlconnector:
-    (InternalError) 1213 (40001): Deadlock found when trying to get lock; try
-                         restarting transaction
+        (OperationalError) (1213, 'Deadlock found when trying to get lock; '
+            'try restarting transaction') <query_str> <query_args>
 
-    postgresql:
-    (TransactionRollbackError) deadlock detected <deadlock_details>
+    mysql+mysqlconnector::
 
+        (InternalError) 1213 (40001): Deadlock found when trying to get lock;
+            try restarting transaction
 
-    ibm_db_sa:
-    SQL0911N The current transaction has been rolled back because of a
-    deadlock or timeout <deadlock details>
+    postgresql::
 
+        (TransactionRollbackError) deadlock detected <deadlock_details>
     """
     raise exception.DBDeadlock(operational_error)
 
@@ -137,9 +133,6 @@ def _default_dupe_key_error(integrity_error, match, engine_name,
                key 'c1'
     N columns - (IntegrityError) 1062 (23000): Duplicate entry 'values
                joined with -' for key 'name_of_our_constraint'
-
-
-
     """
 
     columns = match.group('columns')
@@ -184,7 +177,6 @@ def _sqlite_dupe_key_error(integrity_error, match, engine_name, is_disconnect):
 
     sqlite since 3.8.2:
     (IntegrityError) PRIMARY KEY must be unique
-
     """
     columns = []
     # NOTE(ochuprykov): We can get here by last filter in which there are no
@@ -321,24 +313,6 @@ def _check_database_non_existing(
     raise exception.DBNonExistentDatabase(database, error)
 
 
-@filters("ibm_db_sa", sqla_exc.IntegrityError, r"^.*SQL0803N.*$")
-def _db2_dupe_key_error(integrity_error, match, engine_name, is_disconnect):
-    """Filter for DB2 duplicate key errors.
-
-    N columns - (IntegrityError) SQL0803N  One or more values in the INSERT
-                statement, UPDATE statement, or foreign key update caused by a
-                DELETE statement are not valid because the primary key, unique
-                constraint or unique index identified by "2" constrains table
-                "NOVA.KEY_PAIRS" from having duplicate values for the index
-                key.
-
-    """
-
-    # NOTE(mriedem): The ibm_db_sa integrity error message doesn't provide the
-    # columns so we have to omit that from the DBDuplicateEntry error.
-    raise exception.DBDuplicateEntry([], integrity_error)
-
-
 @filters("mysql", sqla_exc.DBAPIError, r".*\b1146\b")
 def _raise_mysql_table_doesnt_exist_asis(
         error, match, engine_name, is_disconnect):
@@ -400,7 +374,6 @@ def _raise_operational_errors_directly_filter(operational_error,
 @filters("mysql", sqla_exc.InternalError, r".*\(.*(?:1927)")  # noqa
 @filters("mysql", sqla_exc.InternalError, r".*Packet sequence number wrong")  # noqa
 @filters("postgresql", sqla_exc.OperationalError, r".*could not connect to server")  # noqa
-@filters("ibm_db_sa", sqla_exc.OperationalError, r".*(?:30081)")
 def _is_db_connection_error(operational_error, match, engine_name,
                             is_disconnect):
     """Detect the exception as indicating a recoverable error on connect."""
diff --git a/oslo_db/sqlalchemy/provision.py b/oslo_db/sqlalchemy/provision.py
index 5addab4..199cba2 100644
--- a/oslo_db/sqlalchemy/provision.py
+++ b/oslo_db/sqlalchemy/provision.py
@@ -263,7 +263,7 @@ class Backend(object):
             eng = sqlalchemy.create_engine(url)
         except ImportError as i_e:
             # SQLAlchemy performs an "import" of the DBAPI module
-            # within create_engine().  So if ibm_db_sa, cx_oracle etc.
+            # within create_engine().  So if mysql etc.
             # isn't installed, we get an ImportError here.
             LOG.info(
                 "The %(dbapi)s backend is unavailable: %(err)s",
diff --git a/oslo_db/tests/sqlalchemy/test_exc_filters.py b/oslo_db/tests/sqlalchemy/test_exc_filters.py
index 677516d..532c949 100644
--- a/oslo_db/tests/sqlalchemy/test_exc_filters.py
+++ b/oslo_db/tests/sqlalchemy/test_exc_filters.py
@@ -881,28 +881,6 @@ class TestDuplicate(TestsExceptionFilter):
             exception.DBError
         )
 
-    def test_ibm_db_sa(self):
-        self._run_dupe_constraint_test(
-            'ibm_db_sa',
-            'SQL0803N  One or more values in the INSERT statement, UPDATE '
-            'statement, or foreign key update caused by a DELETE statement are'
-            ' not valid because the primary key, unique constraint or unique '
-            'index identified by "2" constrains table "NOVA.KEY_PAIRS" from '
-            'having duplicate values for the index key.',
-            expected_columns=[]
-        )
-
-    def test_ibm_db_sa_notadupe(self):
-        self._not_dupe_constraint_test(
-            'ibm_db_sa',
-            'ALTER TABLE instance_types ADD CONSTRAINT '
-            'uniq_name_x_deleted UNIQUE (name, deleted)',
-            'SQL0542N  The column named "NAME" cannot be a column of a '
-            'primary key or unique key constraint because it can contain null '
-            'values.',
-            exception.DBError
-        )
-
 
 class TestDeadlock(TestsExceptionFilter):
     statement = ('SELECT quota_usages.created_at AS '
@@ -1004,25 +982,6 @@ class TestDeadlock(TestsExceptionFilter):
             orig_exception_cls=self.TransactionRollbackError
         )
 
-    def test_ibm_db_sa_deadlock(self):
-        self._run_deadlock_detect_test(
-            "ibm_db_sa",
-            "SQL0911N The current transaction has been "
-            "rolled back because of a deadlock or timeout",
-            # use the lowest class b.c. I don't know what actual error
-            # class DB2's driver would raise for this
-            orig_exception_cls=self.Error
-        )
-
-    def test_ibm_db_sa_not_deadlock(self):
-        self._not_deadlock_test(
-            "ibm_db_sa",
-            "SQL01234B Some other error.",
-            exception.DBError,
-            "Error",
-            orig_exception_cls=self.Error
-        )
-
 
 class TestDataError(TestsExceptionFilter):
     def _run_bad_data_test(self, dialect_name, message, error_class):
@@ -1256,21 +1215,6 @@ class TestDBDisconnected(TestsExceptionFilter):
             is_disconnect=False
         )
 
-    def test_db2_ping_listener_disconnected(self):
-        self._test_ping_listener_disconnected(
-            "ibm_db_sa",
-            self.OperationalError(
-                'SQL30081N: DB2 Server connection is no longer active')
-        )
-
-    def test_db2_ping_listener_disconnected_regex_only(self):
-        self._test_ping_listener_disconnected(
-            "ibm_db_sa",
-            self.OperationalError(
-                'SQL30081N: DB2 Server connection is no longer active'),
-            is_disconnect=False
-        )
-
     def test_postgresql_ping_listener_disconnected(self):
         self._test_ping_listener_disconnected(
             "postgresql",
@@ -1355,24 +1299,6 @@ class TestDBConnectRetry(TestsExceptionFilter):
             3, 2
         )
 
-    def test_db2_error_positive(self):
-        conn = self._run_test(
-            "ibm_db_sa",
-            self.OperationalError("blah blah -30081 blah blah"),
-            2, -1
-        )
-        # conn is good
-        self.assertEqual(1, conn.scalar(sqla.select([1])))
-
-    def test_db2_error_negative(self):
-        self.assertRaises(
-            sqla.exc.OperationalError,
-            self._run_test,
-            "ibm_db_sa",
-            self.OperationalError("blah blah -39981 blah blah"),
-            2, 3
-        )
-
 
 class TestDBConnectPingWrapping(TestsExceptionFilter):
 
diff --git a/oslo_db/tests/sqlalchemy/test_sqlalchemy.py b/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
index 2dd863a..cd30f15 100644
--- a/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
+++ b/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
@@ -202,22 +202,6 @@ class ProgrammingError(Exception):
     pass
 
 
-class FakeDB2Engine(object):
-
-    class Dialect(object):
-
-        def is_disconnect(self, e, *args):
-            expected_error = ('SQL30081N: DB2 Server connection is no longer '
-                              'active')
-            return (str(e) == expected_error)
-
-    dialect = Dialect()
-    name = 'ibm_db_sa'
-
-    def dispose(self):
-        pass
-
-
 class QueryParamTest(test_base.DbTestCase):
     def _fixture(self):
         from sqlalchemy import create_engine
diff --git a/oslo_db/tests/sqlalchemy/test_utils.py b/oslo_db/tests/sqlalchemy/test_utils.py
index 50f4af1..9923856 100644
--- a/oslo_db/tests/sqlalchemy/test_utils.py
+++ b/oslo_db/tests/sqlalchemy/test_utils.py
@@ -20,7 +20,7 @@ import fixtures
 from oslotest import base as test_base
 import sqlalchemy
 from sqlalchemy.dialects import mysql
-from sqlalchemy import Boolean, Index, Integer, DateTime, String, SmallInteger
+from sqlalchemy import Boolean, Index, Integer, DateTime, String
 from sqlalchemy import CheckConstraint
 from sqlalchemy import MetaData, Table, Column
 from sqlalchemy import ForeignKey, ForeignKeyConstraint
@@ -847,8 +847,7 @@ class TestMigrationUtils(db_test_base._DbTestCase):
         self.assertIsInstance(table.c.deleted.type, Integer)
 
     def test_change_deleted_column_type_to_boolean(self):
-        expected_types = {'mysql': mysql.TINYINT,
-                          'ibm_db_sa': SmallInteger}
+        expected_types = {'mysql': mysql.TINYINT}
         table_name = 'abc'
         table = Table(table_name, self.meta,
                       Column('id', Integer, primary_key=True),
@@ -862,8 +861,7 @@ class TestMigrationUtils(db_test_base._DbTestCase):
                               expected_types.get(self.engine.name, Boolean))
 
     def test_change_deleted_column_type_to_boolean_with_fc(self):
-        expected_types = {'mysql': mysql.TINYINT,
-                          'ibm_db_sa': SmallInteger}
+        expected_types = {'mysql': mysql.TINYINT}
         table_name_1 = 'abc'
         table_name_2 = 'bcd'
 
@@ -1605,7 +1603,6 @@ class TestDialectFunctionDispatcher(test_base.BaseTestCase):
 
         dispatcher("postgresql+pyodbc://", 1)
         dispatcher("mysql+pymysql://", 2)
-        dispatcher("ibm_db_sa+db2://", 3)
         dispatcher("postgresql+psycopg2://", 4)
         dispatcher("postgresql://", 5)
 
@@ -1620,7 +1617,6 @@ class TestDialectFunctionDispatcher(test_base.BaseTestCase):
                 mock.call.mysql_pymysql('mysql+pymysql://', 2),
                 mock.call.mysql('mysql+pymysql://', 2),
                 mock.call.default('mysql+pymysql://', 2),
-                mock.call.default('ibm_db_sa+db2://', 3),
                 mock.call.postgresql_psycopg2('postgresql+psycopg2://', 4),
                 mock.call.postgresql('postgresql+psycopg2://', 4),
                 mock.call.default('postgresql+psycopg2://', 4),
diff --git a/releasenotes/notes/drop-db2-support-6e70fe42268d2238.yaml b/releasenotes/notes/drop-db2-support-6e70fe42268d2238.yaml
new file mode 100644
index 0000000..be32c3b
--- /dev/null
+++ b/releasenotes/notes/drop-db2-support-6e70fe42268d2238.yaml
@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    Checks specific to the DB2 database have been removed. This database
+    has not been supported by any OpenStack project for many years.