Add cleanup migration for indexes.

There are a lot of extra indexes in database (for primary key).

bp: ceilometer-db-sync-models-with-migrations

Change-Id: I44d569de81f078aef27451382baf0a3061f38be2

ceilometer/storage/sqlalchemy/migrate_repo/versions/011_indexes_cleanup.py

@@ -0,0 +1,49 @@
+# -*- encoding: utf-8 -*-
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from sqlalchemy import Index, MetaData, Table
+
+
+INDEXES = {
+    #`table_name`: ((`index_name`, `column`),)
+    "user": (('ix_user_id', 'id'),),
+    "source": (('ix_source_id', 'id'),),
+    "project": (('ix_project_id', 'id'),),
+    "meter": (('ix_meter_id', 'id'),),
+    "alarm": (('ix_alarm_id', 'id'),),
+    "resource": (('ix_resource_id', 'id'),)
+}
+
+
+def upgrade(migrate_engine):
+    meta = MetaData(bind=migrate_engine)
+    load_tables = dict((table_name, Table(table_name, meta, autoload=True))
+                       for table_name in INDEXES.keys())
+    for table_name, indexes in INDEXES.items():
+        table = load_tables[table_name]
+        for index_name, column in indexes:
+            index = Index(index_name, table.c[column])
+            index.drop()
+
+
+def downgrade(migrate_engine):
+    meta = MetaData(bind=migrate_engine)
+    load_tables = dict((table_name, Table(table_name, meta, autoload=True))
+                       for table_name in INDEXES.keys())
+    for table_name, indexes in INDEXES.items():
+        table = load_tables[table_name]
+        for index_name, column in indexes:
+            index = Index(index_name, table.c[column])
+            index.create()