diff --git a/ereuse_devicehub/db.py b/ereuse_devicehub/db.py
index ac06c9d6..5fc091cb 100644
--- a/ereuse_devicehub/db.py
+++ b/ereuse_devicehub/db.py
@@ -1,9 +1,29 @@
 import citext
 from sqlalchemy import event
 from sqlalchemy.dialects import postgresql
+from sqlalchemy.orm import sessionmaker
 from sqlalchemy.sql import expression
 from sqlalchemy_utils import view
-from teal.db import SchemaSQLAlchemy
+from teal.db import SchemaSQLAlchemy, SchemaSession
+
+
+class DhSession(SchemaSession):
+    def final_flush(self):
+        """A regular flush that performs expensive final operations
+        through Devicehub (like saving searches), so it is thought
+        to be used once in each request, at the very end before
+        a commit.
+        """
+        # This was done before with an ``before_commit`` sqlalchemy event
+        # however it is too fragile –it does not detect previously-flushed
+        # things
+        # This solution makes this more aware to the user, although
+        # has the same problem. This is not final solution.
+        # todo a solution would be for this session to save, on every
+        #   flush, all the new / dirty interesting things in a variable
+        #   until DeviceSearch is executed
+        from ereuse_devicehub.resources.device.search import DeviceSearch
+        DeviceSearch.update_modified_devices(session=self)
 
 
 class SQLAlchemy(SchemaSQLAlchemy):
@@ -23,6 +43,9 @@ class SQLAlchemy(SchemaSQLAlchemy):
         if common_schema:
             self.drop_schema(schema='common')
 
+    def create_session(self, options):
+        return sessionmaker(class_=DhSession, db=self, **options)
+
 
 def create_view(name, selectable):
     """Creates a view.
diff --git a/ereuse_devicehub/devicehub.py b/ereuse_devicehub/devicehub.py
index 097a538c..c3925ec8 100644
--- a/ereuse_devicehub/devicehub.py
+++ b/ereuse_devicehub/devicehub.py
@@ -8,7 +8,6 @@ import ereuse_utils.cli
 from ereuse_utils.session import DevicehubClient
 from flask.globals import _app_ctx_stack, g
 from flask_sqlalchemy import SQLAlchemy
-from sqlalchemy import event
 from teal.teal import Teal
 
 from ereuse_devicehub.auth import Auth
@@ -47,16 +46,10 @@ class Devicehub(Teal):
         self.id = inventory
         """The Inventory ID of this instance. In Teal is the app.schema."""
         self.dummy = Dummy(self)
-        self.before_request(self.register_db_events_listeners)
         self.cli.command('regenerate-search')(self.regenerate_search)
         self.cli.command('init-db')(self.init_db)
         self.before_request(self._prepare_request)
 
-    def register_db_events_listeners(self):
-        """Registers the SQLAlchemy event listeners."""
-        # todo can I make it with a global Session only?
-        event.listen(db.session, 'before_commit', DeviceSearch.update_modified_devices)
-
     # noinspection PyMethodOverriding
     @click.option('--name', '-n',
                   default='Test 1',
diff --git a/ereuse_devicehub/dummy/dummy.py b/ereuse_devicehub/dummy/dummy.py
index 511d11a1..4495a821 100644
--- a/ereuse_devicehub/dummy/dummy.py
+++ b/ereuse_devicehub/dummy/dummy.py
@@ -141,9 +141,9 @@ class Dummy:
         assert len(inventory['items'])
 
         i, _ = user.get(res=Device, query=[('search', 'intel')])
-        assert len(i['items']) == 12
+        assert 12 == len(i['items'])
         i, _ = user.get(res=Device, query=[('search', 'pc')])
-        assert len(i['items']) == 14
+        assert 14 == len(i['items'])
 
         # Let's create a set of events for the pc device
         # Make device Ready
diff --git a/ereuse_devicehub/resources/event/models.py b/ereuse_devicehub/resources/event/models.py
index 7e180810..9efc9e0f 100644
--- a/ereuse_devicehub/resources/event/models.py
+++ b/ereuse_devicehub/resources/event/models.py
@@ -10,7 +10,7 @@ import teal.db
 from boltons import urlutils
 from citext import CIText
 from flask import current_app as app, g
-from sqlalchemy import BigInteger, Boolean, CheckConstraint, Column, DateTime, Enum as DBEnum, \
+from sqlalchemy import BigInteger, Boolean, CheckConstraint, Column, Enum as DBEnum, \
     Float, ForeignKey, Integer, Interval, JSON, Numeric, SmallInteger, Unicode, event, orm
 from sqlalchemy.dialects.postgresql import UUID
 from sqlalchemy.ext.declarative import declared_attr
@@ -378,9 +378,10 @@ class Step(db.Model):
     type = Column(Unicode(STR_SM_SIZE), nullable=False)
     num = Column(SmallInteger, primary_key=True)
     severity = Column(teal.db.IntEnum(Severity), default=Severity.Info, nullable=False)
-    start_time = Column(DateTime, nullable=False)
+    start_time = Column(db.TIMESTAMP(timezone=True), nullable=False)
     start_time.comment = Event.start_time.comment
-    end_time = Column(DateTime, CheckConstraint('end_time > start_time'), nullable=False)
+    end_time = Column(db.TIMESTAMP(timezone=True), CheckConstraint('end_time > start_time'),
+                      nullable=False)
     end_time.comment = Event.end_time.comment
 
     erasure = relationship(EraseBasic,
@@ -1187,7 +1188,7 @@ class Trade(JoinedTableMixin, EventWithMultipleDevices):
     This class and its inheritors
     extend `Schema's Trade <http://schema.org/TradeAction>`_.
     """
-    shipping_date = Column(DateTime)
+    shipping_date = Column(db.TIMESTAMP(timezone=True))
     shipping_date.comment = """
             When are the devices going to be ready for shipping?
         """
diff --git a/ereuse_devicehub/resources/event/views.py b/ereuse_devicehub/resources/event/views.py
index a492fb79..0d6e846c 100644
--- a/ereuse_devicehub/resources/event/views.py
+++ b/ereuse_devicehub/resources/event/views.py
@@ -23,9 +23,10 @@ class EventView(View):
         Model = db.Model._decl_class_registry.data[json['type']]()
         event = Model(**e)
         db.session.add(event)
-        db.session.commit()
+        db.session().final_flush()
         ret = self.schema.jsonify(event)
         ret.status_code = 201
+        db.session.commit()
         return ret
 
     def one(self, id: UUID):
@@ -84,7 +85,8 @@ class SnapshotView(View):
             snapshot.events |= rates
 
         db.session.add(snapshot)
-        db.session.commit()
+        db.session().final_flush()
         ret = self.schema.jsonify(snapshot)  # transform it back
         ret.status_code = 201
+        db.session.commit()
         return ret
diff --git a/ereuse_devicehub/resources/lot/views.py b/ereuse_devicehub/resources/lot/views.py
index 96c8c824..eb272c34 100644
--- a/ereuse_devicehub/resources/lot/views.py
+++ b/ereuse_devicehub/resources/lot/views.py
@@ -34,9 +34,10 @@ class LotView(View):
         l = request.get_json()
         lot = Lot(**l)
         db.session.add(lot)
-        db.session.commit()
+        db.session().final_flush()
         ret = self.schema.jsonify(lot)
         ret.status_code = 201
+        db.session.commit()
         return ret
 
     def patch(self, id):
@@ -144,17 +145,21 @@ class LotBaseChildrenView(View):
     def post(self, id: uuid.UUID):
         lot = self.get_lot(id)
         self._post(lot, self.get_ids())
-        db.session.commit()
 
+        db.session().final_flush()
         ret = self.schema.jsonify(lot)
         ret.status_code = 201
+
+        db.session.commit()
         return ret
 
     def delete(self, id: uuid.UUID):
         lot = self.get_lot(id)
         self._delete(lot, self.get_ids())
+        db.session().final_flush()
+        response = self.schema.jsonify(lot)
         db.session.commit()
-        return self.schema.jsonify(lot)
+        return response
 
     def _post(self, lot: Lot, ids: Set[uuid.UUID]):
         raise NotImplementedError
diff --git a/ereuse_devicehub/resources/tag/view.py b/ereuse_devicehub/resources/tag/view.py
index f337c8de..9cfe6d7d 100644
--- a/ereuse_devicehub/resources/tag/view.py
+++ b/ereuse_devicehub/resources/tag/view.py
@@ -32,8 +32,10 @@ class TagView(View):
         tags_id, _ = g.tag_provider.post('/', {}, query=[('num', num)])
         tags = [Tag(id=tag_id, provider=g.inventory.tag_provider) for tag_id in tags_id]
         db.session.add_all(tags)
+        db.session().final_flush()
+        response = things_response(self.schema.dump(tags, many=True, nested=1), code=201)
         db.session.commit()
-        return things_response(self.schema.dump(tags, many=True, nested=1), code=201)
+        return response
 
     def _post_one(self):
         # todo do we use this?
@@ -42,6 +44,7 @@ class TagView(View):
         if tag.like_etag():
             raise CannotCreateETag(tag.id)
         db.session.add(tag)
+        db.session().final_flush()
         db.session.commit()
         return Response(status=201)
 
@@ -69,6 +72,7 @@ class TagDeviceView(View):
                 raise LinkedToAnotherDevice(tag.device_id)
         else:
             tag.device_id = device_id
+        db.session().final_flush()
         db.session.commit()
         return Response(status=204)
 
diff --git a/tests/files/erase-sectors.snapshot.yaml b/tests/files/erase-sectors.snapshot.yaml
index 4331352e..59610ff5 100644
--- a/tests/files/erase-sectors.snapshot.yaml
+++ b/tests/files/erase-sectors.snapshot.yaml
@@ -10,28 +10,28 @@ device:
   model: pc1ml
   manufacturer: pc1mr
 components:
-- type: SolidStateDrive
-  serialNumber: c1s
-  model: c1ml
-  manufacturer: c1mr
-  events:
-  - type: EraseSectors
-    startTime: 2018-06-01T08:12:06
-    endTime: 2018-06-01T09:12:06
-    steps:
-    - type: StepZero
-      severity: Info
-      startTime: 2018-06-01T08:15:00
-      endTime: 2018-06-01T09:16:00
-    - type: StepRandom
-      severity: Info
-      startTime: 2018-06-01T08:16:00
-      endTime: 2018-06-01T09:17:00
-- type: Processor
-  serialNumber: p1s
-  model: p1ml
-  manufacturer: p1mr
-- type: RamModule
-  serialNumber: rm1s
-  model: rm1ml
-  manufacturer: rm1mr
+  - type: SolidStateDrive
+    serialNumber: c1s
+    model: c1ml
+    manufacturer: c1mr
+    events:
+      - type: EraseSectors
+        startTime: '2018-06-01T08:12:06+02:00'
+        endTime: '2018-06-01T09:12:06+02:00'
+        steps:
+          - type: StepZero
+            severity: Info
+            startTime: '2018-06-01T08:15:00+02:00'
+            endTime: '2018-06-01T09:16:00+02:00'
+          - type: StepRandom
+            severity: Info
+            startTime: '2018-06-01T08:16:00+02:00'
+            endTime: '2018-06-01T09:17:00+02:00'
+  - type: Processor
+    serialNumber: p1s
+    model: p1ml
+    manufacturer: p1mr
+  - type: RamModule
+    serialNumber: rm1s
+    model: rm1ml
+    manufacturer: rm1mr
diff --git a/tests/test_snapshot.py b/tests/test_snapshot.py
index 4fda076a..2b7ac98d 100644
--- a/tests/test_snapshot.py
+++ b/tests/test_snapshot.py
@@ -86,7 +86,7 @@ def test_snapshot_post(user: UserClient):
     assert snapshot['components'] == device['components']
 
     assert {c['type'] for c in snapshot['components']} == {m.GraphicCard.t, m.RamModule.t,
-                                                                m.Processor.t}
+                                                           m.Processor.t}
     rate = next(e for e in snapshot['events'] if e['type'] == WorkbenchRate.t)
     rate, _ = user.get(res=Event, item=rate['id'])
     assert rate['device']['id'] == snapshot['device']['id']
@@ -298,7 +298,9 @@ def test_erase_privacy_standards(user: UserClient):
     privacy properties.
     """
     s = file('erase-sectors.snapshot')
+    assert '2018-06-01T09:12:06+02:00' == s['components'][0]['events'][0]['endTime']
     snapshot = snapshot_and_check(user, s, (EraseSectors.t,), perform_second_snapshot=True)
+    assert '2018-06-01T07:12:06+00:00' == snapshot['events'][0]['endTime']
     storage, *_ = snapshot['components']
     assert storage['type'] == 'SolidStateDrive', 'Components must be ordered by input order'
     storage, _ = user.get(res=m.Device, item=storage['id'])  # Let's get storage events too
@@ -306,13 +308,15 @@ def test_erase_privacy_standards(user: UserClient):
     erasure1, _snapshot1, erasure2, _snapshot2 = storage['events']
     assert erasure1['type'] == erasure2['type'] == 'EraseSectors'
     assert _snapshot1['type'] == _snapshot2['type'] == 'Snapshot'
-    assert snapshot == user.get(res=Event, item=_snapshot2['id'])[0]
+    get_snapshot, _ = user.get(res=Event, item=_snapshot2['id'])
+    assert get_snapshot['events'][0]['endTime'] == '2018-06-01T07:12:06+00:00'
+    assert snapshot == get_snapshot
     erasure, _ = user.get(res=Event, item=erasure1['id'])
     assert len(erasure['steps']) == 2
-    assert erasure['steps'][0]['startTime'] == '2018-06-01T08:15:00+00:00'
-    assert erasure['steps'][0]['endTime'] == '2018-06-01T09:16:00+00:00'
-    assert erasure['steps'][1]['startTime'] == '2018-06-01T08:16:00+00:00'
-    assert erasure['steps'][1]['endTime'] == '2018-06-01T09:17:00+00:00'
+    assert erasure['steps'][0]['startTime'] == '2018-06-01T06:15:00+00:00'
+    assert erasure['steps'][0]['endTime'] == '2018-06-01T07:16:00+00:00'
+    assert erasure['steps'][1]['startTime'] == '2018-06-01T06:16:00+00:00'
+    assert erasure['steps'][1]['endTime'] == '2018-06-01T07:17:00+00:00'
     assert erasure['device']['id'] == storage['id']
     step1, step2 = erasure['steps']
     assert step1['type'] == 'StepZero'