Merge pull request #4796 from matrix-org/erikj/factor_out_e2e_keys

 Allow /keys/{changes,query} API to run on worker

11 files changed, 765 insertions, 747 deletions

diff --git a/changelog.d/4796.feature b/changelog.d/4796.feature
new file mode 100644
index 0000000000..9e05560a3f
--- /dev/null
+++ b/changelog.d/4796.feature
@@ -0,0 +1 @@
+Add support for /keys/query and /keys/changes REST endpoints to client_reader worker.
diff --git a/docs/workers.rst b/docs/workers.rst
index 3c18db1b19..d80fc04d2e 100644
--- a/docs/workers.rst
+++ b/docs/workers.rst
@@ -225,6 +225,8 @@ following regular expressions::
     ^/_matrix/client/(api/v1|r0|unstable)/rooms/.*/state$
     ^/_matrix/client/(api/v1|r0|unstable)/login$
     ^/_matrix/client/(api/v1|r0|unstable)/account/3pid$
+    ^/_matrix/client/(api/v1|r0|unstable)/keys/query$
+    ^/_matrix/client/(api/v1|r0|unstable)/keys/changes$
 
 Additionally, the following REST endpoints can be handled, but all requests must
 be routed to the same instance::
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index 5070094cad..beaea64a61 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -33,9 +33,13 @@ from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
 from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
+from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
+from synapse.replication.slave.storage.devices import SlavedDeviceStore
 from synapse.replication.slave.storage.directory import DirectoryStore
 from synapse.replication.slave.storage.events import SlavedEventStore
 from synapse.replication.slave.storage.keys import SlavedKeyStore
+from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
+from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
 from synapse.replication.slave.storage.registration import SlavedRegistrationStore
 from synapse.replication.slave.storage.room import RoomStore
 from synapse.replication.slave.storage.transactions import SlavedTransactionStore
@@ -49,6 +53,7 @@ from synapse.rest.client.v1.room import (
     RoomStateRestServlet,
 )
 from synapse.rest.client.v2_alpha.account import ThreepidRestServlet
+from synapse.rest.client.v2_alpha.keys import KeyChangesServlet, KeyQueryServlet
 from synapse.rest.client.v2_alpha.register import RegisterRestServlet
 from synapse.server import HomeServer
 from synapse.storage.engines import create_engine
@@ -61,6 +66,10 @@ logger = logging.getLogger("synapse.app.client_reader")
 
 
 class ClientReaderSlavedStore(
+    SlavedDeviceInboxStore,
+    SlavedDeviceStore,
+    SlavedReceiptsStore,
+    SlavedPushRuleStore,
     SlavedAccountDataStore,
     SlavedEventStore,
     SlavedKeyStore,
@@ -98,6 +107,8 @@ class ClientReaderServer(HomeServer):
                     RegisterRestServlet(self).register(resource)
                     LoginRestServlet(self).register(resource)
                     ThreepidRestServlet(self).register(resource)
+                    KeyQueryServlet(self).register(resource)
+                    KeyChangesServlet(self).register(resource)
 
                     resources.update({
                         "/_matrix/client/r0": resource,
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index c708c35d4d..c09a7c6280 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -37,13 +37,185 @@ from ._base import BaseHandler
 logger = logging.getLogger(__name__)
 
 
-class DeviceHandler(BaseHandler):
+class DeviceWorkerHandler(BaseHandler):
     def __init__(self, hs):
-        super(DeviceHandler, self).__init__(hs)
+        super(DeviceWorkerHandler, self).__init__(hs)
 
         self.hs = hs
         self.state = hs.get_state_handler()
         self._auth_handler = hs.get_auth_handler()
+
+    @defer.inlineCallbacks
+    def get_devices_by_user(self, user_id):
+        """
+        Retrieve the given user's devices
+
+        Args:
+            user_id (str):
+        Returns:
+            defer.Deferred: list[dict[str, X]]: info on each device
+        """
+
+        device_map = yield self.store.get_devices_by_user(user_id)
+
+        ips = yield self.store.get_last_client_ip_by_device(
+            user_id, device_id=None
+        )
+
+        devices = list(device_map.values())
+        for device in devices:
+            _update_device_from_client_ips(device, ips)
+
+        defer.returnValue(devices)
+
+    @defer.inlineCallbacks
+    def get_device(self, user_id, device_id):
+        """ Retrieve the given device
+
+        Args:
+            user_id (str):
+            device_id (str):
+
+        Returns:
+            defer.Deferred: dict[str, X]: info on the device
+        Raises:
+            errors.NotFoundError: if the device was not found
+        """
+        try:
+            device = yield self.store.get_device(user_id, device_id)
+        except errors.StoreError:
+            raise errors.NotFoundError
+        ips = yield self.store.get_last_client_ip_by_device(
+            user_id, device_id,
+        )
+        _update_device_from_client_ips(device, ips)
+        defer.returnValue(device)
+
+    @measure_func("device.get_user_ids_changed")
+    @defer.inlineCallbacks
+    def get_user_ids_changed(self, user_id, from_token):
+        """Get list of users that have had the devices updated, or have newly
+        joined a room, that `user_id` may be interested in.
+
+        Args:
+            user_id (str)
+            from_token (StreamToken)
+        """
+        now_room_key = yield self.store.get_room_events_max_id()
+
+        room_ids = yield self.store.get_rooms_for_user(user_id)
+
+        # First we check if any devices have changed
+        changed = yield self.store.get_user_whose_devices_changed(
+            from_token.device_list_key
+        )
+
+        # Then work out if any users have since joined
+        rooms_changed = self.store.get_rooms_that_changed(room_ids, from_token.room_key)
+
+        member_events = yield self.store.get_membership_changes_for_user(
+            user_id, from_token.room_key, now_room_key,
+        )
+        rooms_changed.update(event.room_id for event in member_events)
+
+        stream_ordering = RoomStreamToken.parse_stream_token(
+            from_token.room_key
+        ).stream
+
+        possibly_changed = set(changed)
+        possibly_left = set()
+        for room_id in rooms_changed:
+            current_state_ids = yield self.store.get_current_state_ids(room_id)
+
+            # The user may have left the room
+            # TODO: Check if they actually did or if we were just invited.
+            if room_id not in room_ids:
+                for key, event_id in iteritems(current_state_ids):
+                    etype, state_key = key
+                    if etype != EventTypes.Member:
+                        continue
+                    possibly_left.add(state_key)
+                continue
+
+            # Fetch the current state at the time.
+            try:
+                event_ids = yield self.store.get_forward_extremeties_for_room(
+                    room_id, stream_ordering=stream_ordering
+                )
+            except errors.StoreError:
+                # we have purged the stream_ordering index since the stream
+                # ordering: treat it the same as a new room
+                event_ids = []
+
+            # special-case for an empty prev state: include all members
+            # in the changed list
+            if not event_ids:
+                for key, event_id in iteritems(current_state_ids):
+                    etype, state_key = key
+                    if etype != EventTypes.Member:
+                        continue
+                    possibly_changed.add(state_key)
+                continue
+
+            current_member_id = current_state_ids.get((EventTypes.Member, user_id))
+            if not current_member_id:
+                continue
+
+            # mapping from event_id -> state_dict
+            prev_state_ids = yield self.store.get_state_ids_for_events(event_ids)
+
+            # Check if we've joined the room? If so we just blindly add all the users to
+            # the "possibly changed" users.
+            for state_dict in itervalues(prev_state_ids):
+                member_event = state_dict.get((EventTypes.Member, user_id), None)
+                if not member_event or member_event != current_member_id:
+                    for key, event_id in iteritems(current_state_ids):
+                        etype, state_key = key
+                        if etype != EventTypes.Member:
+                            continue
+                        possibly_changed.add(state_key)
+                    break
+
+            # If there has been any change in membership, include them in the
+            # possibly changed list. We'll check if they are joined below,
+            # and we're not toooo worried about spuriously adding users.
+            for key, event_id in iteritems(current_state_ids):
+                etype, state_key = key
+                if etype != EventTypes.Member:
+                    continue
+
+                # check if this member has changed since any of the extremities
+                # at the stream_ordering, and add them to the list if so.
+                for state_dict in itervalues(prev_state_ids):
+                    prev_event_id = state_dict.get(key, None)
+                    if not prev_event_id or prev_event_id != event_id:
+                        if state_key != user_id:
+                            possibly_changed.add(state_key)
+                        break
+
+        if possibly_changed or possibly_left:
+            users_who_share_room = yield self.store.get_users_who_share_room_with_user(
+                user_id
+            )
+
+            # Take the intersection of the users whose devices may have changed
+            # and those that actually still share a room with the user
+            possibly_joined = possibly_changed & users_who_share_room
+            possibly_left = (possibly_changed | possibly_left) - users_who_share_room
+        else:
+            possibly_joined = []
+            possibly_left = []
+
+        defer.returnValue({
+            "changed": list(possibly_joined),
+            "left": list(possibly_left),
+        })
+
+
+class DeviceHandler(DeviceWorkerHandler):
+    def __init__(self, hs):
+        super(DeviceHandler, self).__init__(hs)
+
         self.federation_sender = hs.get_federation_sender()
 
         self._edu_updater = DeviceListEduUpdater(hs, self)
@@ -104,52 +276,6 @@ class DeviceHandler(BaseHandler):
         raise errors.StoreError(500, "Couldn't generate a device ID.")
 
     @defer.inlineCallbacks
-    def get_devices_by_user(self, user_id):
-        """
-        Retrieve the given user's devices
-
-        Args:
-            user_id (str):
-        Returns:
-            defer.Deferred: list[dict[str, X]]: info on each device
-        """
-
-        device_map = yield self.store.get_devices_by_user(user_id)
-
-        ips = yield self.store.get_last_client_ip_by_device(
-            user_id, device_id=None
-        )
-
-        devices = list(device_map.values())
-        for device in devices:
-            _update_device_from_client_ips(device, ips)
-
-        defer.returnValue(devices)
-
-    @defer.inlineCallbacks
-    def get_device(self, user_id, device_id):
-        """ Retrieve the given device
-
-        Args:
-            user_id (str):
-            device_id (str):
-
-        Returns:
-            defer.Deferred: dict[str, X]: info on the device
-        Raises:
-            errors.NotFoundError: if the device was not found
-        """
-        try:
-            device = yield self.store.get_device(user_id, device_id)
-        except errors.StoreError:
-            raise errors.NotFoundError
-        ips = yield self.store.get_last_client_ip_by_device(
-            user_id, device_id,
-        )
-        _update_device_from_client_ips(device, ips)
-        defer.returnValue(device)
-
-    @defer.inlineCallbacks
     def delete_device(self, user_id, device_id):
         """ Delete the given device
 
@@ -287,126 +413,6 @@ class DeviceHandler(BaseHandler):
             for host in hosts:
                 self.federation_sender.send_device_messages(host)
 
-    @measure_func("device.get_user_ids_changed")
-    @defer.inlineCallbacks
-    def get_user_ids_changed(self, user_id, from_token):
-        """Get list of users that have had the devices updated, or have newly
-        joined a room, that `user_id` may be interested in.
-
-        Args:
-            user_id (str)
-            from_token (StreamToken)
-        """
-        now_token = yield self.hs.get_event_sources().get_current_token()
-
-        room_ids = yield self.store.get_rooms_for_user(user_id)
-
-        # First we check if any devices have changed
-        changed = yield self.store.get_user_whose_devices_changed(
-            from_token.device_list_key
-        )
-
-        # Then work out if any users have since joined
-        rooms_changed = self.store.get_rooms_that_changed(room_ids, from_token.room_key)
-
-        member_events = yield self.store.get_membership_changes_for_user(
-            user_id, from_token.room_key, now_token.room_key
-        )
-        rooms_changed.update(event.room_id for event in member_events)
-
-        stream_ordering = RoomStreamToken.parse_stream_token(
-            from_token.room_key
-        ).stream
-
-        possibly_changed = set(changed)
-        possibly_left = set()
-        for room_id in rooms_changed:
-            current_state_ids = yield self.store.get_current_state_ids(room_id)
-
-            # The user may have left the room
-            # TODO: Check if they actually did or if we were just invited.
-            if room_id not in room_ids:
-                for key, event_id in iteritems(current_state_ids):
-                    etype, state_key = key
-                    if etype != EventTypes.Member:
-                        continue
-                    possibly_left.add(state_key)
-                continue
-
-            # Fetch the current state at the time.
-            try:
-                event_ids = yield self.store.get_forward_extremeties_for_room(
-                    room_id, stream_ordering=stream_ordering
-                )
-            except errors.StoreError:
-                # we have purged the stream_ordering index since the stream
-                # ordering: treat it the same as a new room
-                event_ids = []
-
-            # special-case for an empty prev state: include all members
-            # in the changed list
-            if not event_ids:
-                for key, event_id in iteritems(current_state_ids):
-                    etype, state_key = key
-                    if etype != EventTypes.Member:
-                        continue
-                    possibly_changed.add(state_key)
-                continue
-
-            current_member_id = current_state_ids.get((EventTypes.Member, user_id))
-            if not current_member_id:
-                continue
-
-            # mapping from event_id -> state_dict
-            prev_state_ids = yield self.store.get_state_ids_for_events(event_ids)
-
-            # Check if we've joined the room? If so we just blindly add all the users to
-            # the "possibly changed" users.
-            for state_dict in itervalues(prev_state_ids):
-                member_event = state_dict.get((EventTypes.Member, user_id), None)
-                if not member_event or member_event != current_member_id:
-                    for key, event_id in iteritems(current_state_ids):
-                        etype, state_key = key
-                        if etype != EventTypes.Member:
-                            continue
-                        possibly_changed.add(state_key)
-                    break
-
-            # If there has been any change in membership, include them in the
-            # possibly changed list. We'll check if they are joined below,
-            # and we're not toooo worried about spuriously adding users.
-            for key, event_id in iteritems(current_state_ids):
-                etype, state_key = key
-                if etype != EventTypes.Member:
-                    continue
-
-                # check if this member has changed since any of the extremities
-                # at the stream_ordering, and add them to the list if so.
-                for state_dict in itervalues(prev_state_ids):
-                    prev_event_id = state_dict.get(key, None)
-                    if not prev_event_id or prev_event_id != event_id:
-                        if state_key != user_id:
-                            possibly_changed.add(state_key)
-                        break
-
-        if possibly_changed or possibly_left:
-            users_who_share_room = yield self.store.get_users_who_share_room_with_user(
-                user_id
-            )
-
-            # Take the intersection of the users whose devices may have changed
-            # and those that actually still share a room with the user
-            possibly_joined = possibly_changed & users_who_share_room
-            possibly_left = (possibly_changed | possibly_left) - users_who_share_room
-        else:
-            possibly_joined = []
-            possibly_left = []
-
-        defer.returnValue({
-            "changed": list(possibly_joined),
-            "left": list(possibly_left),
-        })
-
     @defer.inlineCallbacks
     def on_federation_query_user_devices(self, user_id):
         stream_id, devices = yield self.store.get_devices_with_keys_by_user(user_id)
diff --git a/synapse/replication/slave/storage/deviceinbox.py b/synapse/replication/slave/storage/deviceinbox.py
index 4f19fd35aa..4d59778863 100644
--- a/synapse/replication/slave/storage/deviceinbox.py
+++ b/synapse/replication/slave/storage/deviceinbox.py
@@ -13,15 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage import DataStore
+from synapse.replication.slave.storage._base import BaseSlavedStore
+from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
+from synapse.storage.deviceinbox import DeviceInboxWorkerStore
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
-from ._base import BaseSlavedStore, __func__
-from ._slaved_id_tracker import SlavedIdTracker
 
-
-class SlavedDeviceInboxStore(BaseSlavedStore):
+class SlavedDeviceInboxStore(DeviceInboxWorkerStore, BaseSlavedStore):
     def __init__(self, db_conn, hs):
         super(SlavedDeviceInboxStore, self).__init__(db_conn, hs)
         self._device_inbox_id_gen = SlavedIdTracker(
@@ -43,12 +42,6 @@ class SlavedDeviceInboxStore(BaseSlavedStore):
             expiry_ms=30 * 60 * 1000,
         )
 
-    get_to_device_stream_token = __func__(DataStore.get_to_device_stream_token)
-    get_new_messages_for_device = __func__(DataStore.get_new_messages_for_device)
-    get_new_device_msgs_for_remote = __func__(DataStore.get_new_device_msgs_for_remote)
-    delete_messages_for_device = __func__(DataStore.delete_messages_for_device)
-    delete_device_msgs_for_remote = __func__(DataStore.delete_device_msgs_for_remote)
-
     def stream_positions(self):
         result = super(SlavedDeviceInboxStore, self).stream_positions()
         result["to_device"] = self._device_inbox_id_gen.get_current_token()
diff --git a/synapse/replication/slave/storage/devices.py b/synapse/replication/slave/storage/devices.py
index ec2fd561cc..16c9a162c5 100644
--- a/synapse/replication/slave/storage/devices.py
+++ b/synapse/replication/slave/storage/devices.py
@@ -13,15 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage import DataStore
-from synapse.storage.end_to_end_keys import EndToEndKeyStore
+from synapse.replication.slave.storage._base import BaseSlavedStore
+from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
+from synapse.storage.devices import DeviceWorkerStore
+from synapse.storage.end_to_end_keys import EndToEndKeyWorkerStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
-from ._base import BaseSlavedStore, __func__
-from ._slaved_id_tracker import SlavedIdTracker
 
-
-class SlavedDeviceStore(BaseSlavedStore):
+class SlavedDeviceStore(EndToEndKeyWorkerStore, DeviceWorkerStore, BaseSlavedStore):
     def __init__(self, db_conn, hs):
         super(SlavedDeviceStore, self).__init__(db_conn, hs)
 
@@ -38,17 +37,6 @@ class SlavedDeviceStore(BaseSlavedStore):
             "DeviceListFederationStreamChangeCache", device_list_max,
         )
 
-    get_device_stream_token = __func__(DataStore.get_device_stream_token)
-    get_user_whose_devices_changed = __func__(DataStore.get_user_whose_devices_changed)
-    get_devices_by_remote = __func__(DataStore.get_devices_by_remote)
-    _get_devices_by_remote_txn = __func__(DataStore._get_devices_by_remote_txn)
-    _get_e2e_device_keys_txn = __func__(DataStore._get_e2e_device_keys_txn)
-    mark_as_sent_devices_by_remote = __func__(DataStore.mark_as_sent_devices_by_remote)
-    _mark_as_sent_devices_by_remote_txn = (
-        __func__(DataStore._mark_as_sent_devices_by_remote_txn)
-    )
-    count_e2e_one_time_keys = EndToEndKeyStore.__dict__["count_e2e_one_time_keys"]
-
     def stream_positions(self):
         result = super(SlavedDeviceStore, self).stream_positions()
         result["device_lists"] = self._device_list_id_gen.get_current_token()
@@ -58,14 +46,23 @@ class SlavedDeviceStore(BaseSlavedStore):
         if stream_name == "device_lists":
             self._device_list_id_gen.advance(token)
             for row in rows:
-                self._device_list_stream_cache.entity_has_changed(
-                    row.user_id, token
+                self._invalidate_caches_for_devices(
+                    token, row.user_id, row.destination,
                 )
-
-                if row.destination:
-                    self._device_list_federation_stream_cache.entity_has_changed(
-                        row.destination, token
-                    )
         return super(SlavedDeviceStore, self).process_replication_rows(
             stream_name, token, rows
         )
+
+    def _invalidate_caches_for_devices(self, token, user_id, destination):
+        self._device_list_stream_cache.entity_has_changed(
+            user_id, token
+        )
+
+        if destination:
+            self._device_list_federation_stream_cache.entity_has_changed(
+                destination, token
+            )
+
+        self._get_cached_devices_for_user.invalidate((user_id,))
+        self._get_cached_user_device.invalidate_many((user_id,))
+        self.get_device_list_last_stream_id_for_remote.invalidate((user_id,))
diff --git a/synapse/replication/slave/storage/push_rule.py b/synapse/replication/slave/storage/push_rule.py
index f0200c1e98..45fc913c52 100644
--- a/synapse/replication/slave/storage/push_rule.py
+++ b/synapse/replication/slave/storage/push_rule.py
@@ -20,7 +20,7 @@ from ._slaved_id_tracker import SlavedIdTracker
 from .events import SlavedEventStore
 
 
-class SlavedPushRuleStore(PushRulesWorkerStore, SlavedEventStore):
+class SlavedPushRuleStore(SlavedEventStore, PushRulesWorkerStore):
     def __init__(self, db_conn, hs):
         self._push_rules_stream_id_gen = SlavedIdTracker(
             db_conn, "push_rules_stream", "stream_id",
diff --git a/synapse/server.py b/synapse/server.py
index 4d364fccce..4323e7ff12 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -51,7 +51,7 @@ from synapse.handlers.acme import AcmeHandler
 from synapse.handlers.appservice import ApplicationServicesHandler
 from synapse.handlers.auth import AuthHandler, MacaroonGenerator
 from synapse.handlers.deactivate_account import DeactivateAccountHandler
-from synapse.handlers.device import DeviceHandler
+from synapse.handlers.device import DeviceHandler, DeviceWorkerHandler
 from synapse.handlers.devicemessage import DeviceMessageHandler
 from synapse.handlers.e2e_keys import E2eKeysHandler
 from synapse.handlers.e2e_room_keys import E2eRoomKeysHandler
@@ -307,7 +307,10 @@ class HomeServer(object):
         return MacaroonGenerator(self)
 
     def build_device_handler(self):
-        return DeviceHandler(self)
+        if self.config.worker_app:
+            return DeviceWorkerHandler(self)
+        else:
+            return DeviceHandler(self)
 
     def build_device_message_handler(self):
         return DeviceMessageHandler(self)
diff --git a/synapse/storage/deviceinbox.py b/synapse/storage/deviceinbox.py
index e06b0bc56d..e6a42a53bb 100644
--- a/synapse/storage/deviceinbox.py
+++ b/synapse/storage/deviceinbox.py
@@ -19,14 +19,174 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
+from synapse.storage._base import SQLBaseStore
+from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.util.caches.expiringcache import ExpiringCache
 
-from .background_updates import BackgroundUpdateStore
-
 logger = logging.getLogger(__name__)
 
 
-class DeviceInboxStore(BackgroundUpdateStore):
+class DeviceInboxWorkerStore(SQLBaseStore):
+    def get_to_device_stream_token(self):
+        return self._device_inbox_id_gen.get_current_token()
+
+    def get_new_messages_for_device(
+        self, user_id, device_id, last_stream_id, current_stream_id, limit=100
+    ):
+        """
+        Args:
+            user_id(str): The recipient user_id.
+            device_id(str): The recipient device_id.
+            current_stream_id(int): The current position of the to device
+                message stream.
+        Returns:
+            Deferred ([dict], int): List of messages for the device and where
+                in the stream the messages got to.
+        """
+        has_changed = self._device_inbox_stream_cache.has_entity_changed(
+            user_id, last_stream_id
+        )
+        if not has_changed:
+            return defer.succeed(([], current_stream_id))
+
+        def get_new_messages_for_device_txn(txn):
+            sql = (
+                "SELECT stream_id, message_json FROM device_inbox"
+                " WHERE user_id = ? AND device_id = ?"
+                " AND ? < stream_id AND stream_id <= ?"
+                " ORDER BY stream_id ASC"
+                " LIMIT ?"
+            )
+            txn.execute(sql, (
+                user_id, device_id, last_stream_id, current_stream_id, limit
+            ))
+            messages = []
+            for row in txn:
+                stream_pos = row[0]
+                messages.append(json.loads(row[1]))
+            if len(messages) < limit:
+                stream_pos = current_stream_id
+            return (messages, stream_pos)
+
+        return self.runInteraction(
+            "get_new_messages_for_device", get_new_messages_for_device_txn,
+        )
+
+    @defer.inlineCallbacks
+    def delete_messages_for_device(self, user_id, device_id, up_to_stream_id):
+        """
+        Args:
+            user_id(str): The recipient user_id.
+            device_id(str): The recipient device_id.
+            up_to_stream_id(int): Where to delete messages up to.
+        Returns:
+            A deferred that resolves to the number of messages deleted.
+        """
+        # If we have cached the last stream id we've deleted up to, we can
+        # check if there is likely to be anything that needs deleting
+        last_deleted_stream_id = self._last_device_delete_cache.get(
+            (user_id, device_id), None
+        )
+        if last_deleted_stream_id:
+            has_changed = self._device_inbox_stream_cache.has_entity_changed(
+                user_id, last_deleted_stream_id
+            )
+            if not has_changed:
+                defer.returnValue(0)
+
+        def delete_messages_for_device_txn(txn):
+            sql = (
+                "DELETE FROM device_inbox"
+                " WHERE user_id = ? AND device_id = ?"
+                " AND stream_id <= ?"
+            )
+            txn.execute(sql, (user_id, device_id, up_to_stream_id))
+            return txn.rowcount
+
+        count = yield self.runInteraction(
+            "delete_messages_for_device", delete_messages_for_device_txn
+        )
+
+        # Update the cache, ensuring that we only ever increase the value
+        last_deleted_stream_id = self._last_device_delete_cache.get(
+            (user_id, device_id), 0
+        )
+        self._last_device_delete_cache[(user_id, device_id)] = max(
+            last_deleted_stream_id, up_to_stream_id
+        )
+
+        defer.returnValue(count)
+
+    def get_new_device_msgs_for_remote(
+        self, destination, last_stream_id, current_stream_id, limit=100
+    ):
+        """
+        Args:
+            destination(str): The name of the remote server.
+            last_stream_id(int|long): The last position of the device message stream
+                that the server sent up to.
+            current_stream_id(int|long): The current position of the device
+                message stream.
+        Returns:
+            Deferred ([dict], int|long): List of messages for the device and where
+                in the stream the messages got to.
+        """
+
+        has_changed = self._device_federation_outbox_stream_cache.has_entity_changed(
+            destination, last_stream_id
+        )
+        if not has_changed or last_stream_id == current_stream_id:
+            return defer.succeed(([], current_stream_id))
+
+        def get_new_messages_for_remote_destination_txn(txn):
+            sql = (
+                "SELECT stream_id, messages_json FROM device_federation_outbox"
+                " WHERE destination = ?"
+                " AND ? < stream_id AND stream_id <= ?"
+                " ORDER BY stream_id ASC"
+                " LIMIT ?"
+            )
+            txn.execute(sql, (
+                destination, last_stream_id, current_stream_id, limit
+            ))
+            messages = []
+            for row in txn:
+                stream_pos = row[0]
+                messages.append(json.loads(row[1]))
+            if len(messages) < limit:
+                stream_pos = current_stream_id
+            return (messages, stream_pos)
+
+        return self.runInteraction(
+            "get_new_device_msgs_for_remote",
+            get_new_messages_for_remote_destination_txn,
+        )
+
+    def delete_device_msgs_for_remote(self, destination, up_to_stream_id):
+        """Used to delete messages when the remote destination acknowledges
+        their receipt.
+
+        Args:
+            destination(str): The destination server_name
+            up_to_stream_id(int): Where to delete messages up to.
+        Returns:
+            A deferred that resolves when the messages have been deleted.
+        """
+        def delete_messages_for_remote_destination_txn(txn):
+            sql = (
+                "DELETE FROM device_federation_outbox"
+                " WHERE destination = ?"
+                " AND stream_id <= ?"
+            )
+            txn.execute(sql, (destination, up_to_stream_id))
+
+        return self.runInteraction(
+            "delete_device_msgs_for_remote",
+            delete_messages_for_remote_destination_txn
+        )
+
+
+class DeviceInboxStore(DeviceInboxWorkerStore, BackgroundUpdateStore):
     DEVICE_INBOX_STREAM_ID = "device_inbox_stream_drop"
 
     def __init__(self, db_conn, hs):
@@ -220,93 +380,6 @@ class DeviceInboxStore(BackgroundUpdateStore):
 
         txn.executemany(sql, rows)
 
-    def get_new_messages_for_device(
-        self, user_id, device_id, last_stream_id, current_stream_id, limit=100
-    ):
-        """
-        Args:
-            user_id(str): The recipient user_id.
-            device_id(str): The recipient device_id.
-            current_stream_id(int): The current position of the to device
-                message stream.
-        Returns:
-            Deferred ([dict], int): List of messages for the device and where
-                in the stream the messages got to.
-        """
-        has_changed = self._device_inbox_stream_cache.has_entity_changed(
-            user_id, last_stream_id
-        )
-        if not has_changed:
-            return defer.succeed(([], current_stream_id))
-
-        def get_new_messages_for_device_txn(txn):
-            sql = (
-                "SELECT stream_id, message_json FROM device_inbox"
-                " WHERE user_id = ? AND device_id = ?"
-                " AND ? < stream_id AND stream_id <= ?"
-                " ORDER BY stream_id ASC"
-                " LIMIT ?"
-            )
-            txn.execute(sql, (
-                user_id, device_id, last_stream_id, current_stream_id, limit
-            ))
-            messages = []
-            for row in txn:
-                stream_pos = row[0]
-                messages.append(json.loads(row[1]))
-            if len(messages) < limit:
-                stream_pos = current_stream_id
-            return (messages, stream_pos)
-
-        return self.runInteraction(
-            "get_new_messages_for_device", get_new_messages_for_device_txn,
-        )
-
-    @defer.inlineCallbacks
-    def delete_messages_for_device(self, user_id, device_id, up_to_stream_id):
-        """
-        Args:
-            user_id(str): The recipient user_id.
-            device_id(str): The recipient device_id.
-            up_to_stream_id(int): Where to delete messages up to.
-        Returns:
-            A deferred that resolves to the number of messages deleted.
-        """
-        # If we have cached the last stream id we've deleted up to, we can
-        # check if there is likely to be anything that needs deleting
-        last_deleted_stream_id = self._last_device_delete_cache.get(
-            (user_id, device_id), None
-        )
-        if last_deleted_stream_id:
-            has_changed = self._device_inbox_stream_cache.has_entity_changed(
-                user_id, last_deleted_stream_id
-            )
-            if not has_changed:
-                defer.returnValue(0)
-
-        def delete_messages_for_device_txn(txn):
-            sql = (
-                "DELETE FROM device_inbox"
-                " WHERE user_id = ? AND device_id = ?"
-                " AND stream_id <= ?"
-            )
-            txn.execute(sql, (user_id, device_id, up_to_stream_id))
-            return txn.rowcount
-
-        count = yield self.runInteraction(
-            "delete_messages_for_device", delete_messages_for_device_txn
-        )
-
-        # Update the cache, ensuring that we only ever increase the value
-        last_deleted_stream_id = self._last_device_delete_cache.get(
-            (user_id, device_id), 0
-        )
-        self._last_device_delete_cache[(user_id, device_id)] = max(
-            last_deleted_stream_id, up_to_stream_id
-        )
-
-        defer.returnValue(count)
-
     def get_all_new_device_messages(self, last_pos, current_pos, limit):
         """
         Args:
@@ -351,77 +424,6 @@ class DeviceInboxStore(BackgroundUpdateStore):
             "get_all_new_device_messages", get_all_new_device_messages_txn
         )
 
-    def get_to_device_stream_token(self):
-        return self._device_inbox_id_gen.get_current_token()
-
-    def get_new_device_msgs_for_remote(
-        self, destination, last_stream_id, current_stream_id, limit=100
-    ):
-        """
-        Args:
-            destination(str): The name of the remote server.
-            last_stream_id(int|long): The last position of the device message stream
-                that the server sent up to.
-            current_stream_id(int|long): The current position of the device
-                message stream.
-        Returns:
-            Deferred ([dict], int|long): List of messages for the device and where
-                in the stream the messages got to.
-        """
-
-        has_changed = self._device_federation_outbox_stream_cache.has_entity_changed(
-            destination, last_stream_id
-        )
-        if not has_changed or last_stream_id == current_stream_id:
-            return defer.succeed(([], current_stream_id))
-
-        def get_new_messages_for_remote_destination_txn(txn):
-            sql = (
-                "SELECT stream_id, messages_json FROM device_federation_outbox"
-                " WHERE destination = ?"
-                " AND ? < stream_id AND stream_id <= ?"
-                " ORDER BY stream_id ASC"
-                " LIMIT ?"
-            )
-            txn.execute(sql, (
-                destination, last_stream_id, current_stream_id, limit
-            ))
-            messages = []
-            for row in txn:
-                stream_pos = row[0]
-                messages.append(json.loads(row[1]))
-            if len(messages) < limit:
-                stream_pos = current_stream_id
-            return (messages, stream_pos)
-
-        return self.runInteraction(
-            "get_new_device_msgs_for_remote",
-            get_new_messages_for_remote_destination_txn,
-        )
-
-    def delete_device_msgs_for_remote(self, destination, up_to_stream_id):
-        """Used to delete messages when the remote destination acknowledges
-        their receipt.
-
-        Args:
-            destination(str): The destination server_name
-            up_to_stream_id(int): Where to delete messages up to.
-        Returns:
-            A deferred that resolves when the messages have been deleted.
-        """
-        def delete_messages_for_remote_destination_txn(txn):
-            sql = (
-                "DELETE FROM device_federation_outbox"
-                " WHERE destination = ?"
-                " AND stream_id <= ?"
-            )
-            txn.execute(sql, (destination, up_to_stream_id))
-
-        return self.runInteraction(
-            "delete_device_msgs_for_remote",
-            delete_messages_for_remote_destination_txn
-        )
-
     @defer.inlineCallbacks
     def _background_drop_index_device_inbox(self, progress, batch_size):
         def reindex_txn(conn):
diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index ecdab34e7d..e716dc1437 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -22,11 +22,10 @@ from twisted.internet import defer
 
 from synapse.api.errors import StoreError
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.storage._base import Cache, SQLBaseStore, db_to_json
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
 
-from ._base import Cache, db_to_json
-
 logger = logging.getLogger(__name__)
 
 DROP_DEVICE_LIST_STREAMS_NON_UNIQUE_INDEXES = (
@@ -34,7 +33,343 @@ DROP_DEVICE_LIST_STREAMS_NON_UNIQUE_INDEXES = (
 )
 
 
-class DeviceStore(BackgroundUpdateStore):
+class DeviceWorkerStore(SQLBaseStore):
+    def get_device(self, user_id, device_id):
+        """Retrieve a device.
+
+        Args:
+            user_id (str): The ID of the user which owns the device
+            device_id (str): The ID of the device to retrieve
+        Returns:
+            defer.Deferred for a dict containing the device information
+        Raises:
+            StoreError: if the device is not found
+        """
+        return self._simple_select_one(
+            table="devices",
+            keyvalues={"user_id": user_id, "device_id": device_id},
+            retcols=("user_id", "device_id", "display_name"),
+            desc="get_device",
+        )
+
+    @defer.inlineCallbacks
+    def get_devices_by_user(self, user_id):
+        """Retrieve all of a user's registered devices.
+
+        Args:
+            user_id (str):
+        Returns:
+            defer.Deferred: resolves to a dict from device_id to a dict
+            containing "device_id", "user_id" and "display_name" for each
+            device.
+        """
+        devices = yield self._simple_select_list(
+            table="devices",
+            keyvalues={"user_id": user_id},
+            retcols=("user_id", "device_id", "display_name"),
+            desc="get_devices_by_user"
+        )
+
+        defer.returnValue({d["device_id"]: d for d in devices})
+
+    def get_devices_by_remote(self, destination, from_stream_id):
+        """Get stream of updates to send to remote servers
+
+        Returns:
+            (int, list[dict]): current stream id and list of updates
+        """
+        now_stream_id = self._device_list_id_gen.get_current_token()
+
+        has_changed = self._device_list_federation_stream_cache.has_entity_changed(
+            destination, int(from_stream_id)
+        )
+        if not has_changed:
+            return (now_stream_id, [])
+
+        return self.runInteraction(
+            "get_devices_by_remote", self._get_devices_by_remote_txn,
+            destination, from_stream_id, now_stream_id,
+        )
+
+    def _get_devices_by_remote_txn(self, txn, destination, from_stream_id,
+                                   now_stream_id):
+        sql = """
+            SELECT user_id, device_id, max(stream_id) FROM device_lists_outbound_pokes
+            WHERE destination = ? AND ? < stream_id AND stream_id <= ? AND sent = ?
+            GROUP BY user_id, device_id
+            LIMIT 20
+        """
+        txn.execute(
+            sql, (destination, from_stream_id, now_stream_id, False)
+        )
+
+        # maps (user_id, device_id) -> stream_id
+        query_map = {(r[0], r[1]): r[2] for r in txn}
+        if not query_map:
+            return (now_stream_id, [])
+
+        if len(query_map) >= 20:
+            now_stream_id = max(stream_id for stream_id in itervalues(query_map))
+
+        devices = self._get_e2e_device_keys_txn(
+            txn, query_map.keys(), include_all_devices=True, include_deleted_devices=True
+        )
+
+        prev_sent_id_sql = """
+            SELECT coalesce(max(stream_id), 0) as stream_id
+            FROM device_lists_outbound_last_success
+            WHERE destination = ? AND user_id = ? AND stream_id <= ?
+        """
+
+        results = []
+        for user_id, user_devices in iteritems(devices):
+            # The prev_id for the first row is always the last row before
+            # `from_stream_id`
+            txn.execute(prev_sent_id_sql, (destination, user_id, from_stream_id))
+            rows = txn.fetchall()
+            prev_id = rows[0][0]
+            for device_id, device in iteritems(user_devices):
+                stream_id = query_map[(user_id, device_id)]
+                result = {
+                    "user_id": user_id,
+                    "device_id": device_id,
+                    "prev_id": [prev_id] if prev_id else [],
+                    "stream_id": stream_id,
+                }
+
+                prev_id = stream_id
+
+                if device is not None:
+                    key_json = device.get("key_json", None)
+                    if key_json:
+                        result["keys"] = db_to_json(key_json)
+                    device_display_name = device.get("device_display_name", None)
+                    if device_display_name:
+                        result["device_display_name"] = device_display_name
+                else:
+                    result["deleted"] = True
+
+                results.append(result)
+
+        return (now_stream_id, results)
+
+    def mark_as_sent_devices_by_remote(self, destination, stream_id):
+        """Mark that updates have successfully been sent to the destination.
+        """
+        return self.runInteraction(
+            "mark_as_sent_devices_by_remote", self._mark_as_sent_devices_by_remote_txn,
+            destination, stream_id,
+        )
+
+    def _mark_as_sent_devices_by_remote_txn(self, txn, destination, stream_id):
+        # We update the device_lists_outbound_last_success with the successfully
+        # poked users. We do the join to see which users need to be inserted and
+        # which updated.
+        sql = """
+            SELECT user_id, coalesce(max(o.stream_id), 0), (max(s.stream_id) IS NOT NULL)
+            FROM device_lists_outbound_pokes as o
+            LEFT JOIN device_lists_outbound_last_success as s
+                USING (destination, user_id)
+            WHERE destination = ? AND o.stream_id <= ?
+            GROUP BY user_id
+        """
+        txn.execute(sql, (destination, stream_id,))
+        rows = txn.fetchall()
+
+        sql = """
+            UPDATE device_lists_outbound_last_success
+            SET stream_id = ?
+            WHERE destination = ? AND user_id = ?
+        """
+        txn.executemany(
+            sql, ((row[1], destination, row[0],) for row in rows if row[2])
+        )
+
+        sql = """
+            INSERT INTO device_lists_outbound_last_success
+            (destination, user_id, stream_id) VALUES (?, ?, ?)
+        """
+        txn.executemany(
+            sql, ((destination, row[0], row[1],) for row in rows if not row[2])
+        )
+
+        # Delete all sent outbound pokes
+        sql = """
+            DELETE FROM device_lists_outbound_pokes
+            WHERE destination = ? AND stream_id <= ?
+        """
+        txn.execute(sql, (destination, stream_id,))
+
+    def get_device_stream_token(self):
+        return self._device_list_id_gen.get_current_token()
+
+    @defer.inlineCallbacks
+    def get_user_devices_from_cache(self, query_list):
+        """Get the devices (and keys if any) for remote users from the cache.
+
+        Args:
+            query_list(list): List of (user_id, device_ids), if device_ids is
+                falsey then return all device ids for that user.
+
+        Returns:
+            (user_ids_not_in_cache, results_map), where user_ids_not_in_cache is
+            a set of user_ids and results_map is a mapping of
+            user_id -> device_id -> device_info
+        """
+        user_ids = set(user_id for user_id, _ in query_list)
+        user_map = yield self.get_device_list_last_stream_id_for_remotes(list(user_ids))
+        user_ids_in_cache = set(
+            user_id for user_id, stream_id in user_map.items() if stream_id
+        )
+        user_ids_not_in_cache = user_ids - user_ids_in_cache
+
+        results = {}
+        for user_id, device_id in query_list:
+            if user_id not in user_ids_in_cache:
+                continue
+
+            if device_id:
+                device = yield self._get_cached_user_device(user_id, device_id)
+                results.setdefault(user_id, {})[device_id] = device
+            else:
+                results[user_id] = yield self._get_cached_devices_for_user(user_id)
+
+        defer.returnValue((user_ids_not_in_cache, results))
+
+    @cachedInlineCallbacks(num_args=2, tree=True)
+    def _get_cached_user_device(self, user_id, device_id):
+        content = yield self._simple_select_one_onecol(
+            table="device_lists_remote_cache",
+            keyvalues={
+                "user_id": user_id,
+                "device_id": device_id,
+            },
+            retcol="content",
+            desc="_get_cached_user_device",
+        )
+        defer.returnValue(db_to_json(content))
+
+    @cachedInlineCallbacks()
+    def _get_cached_devices_for_user(self, user_id):
+        devices = yield self._simple_select_list(
+            table="device_lists_remote_cache",
+            keyvalues={
+                "user_id": user_id,
+            },
+            retcols=("device_id", "content"),
+            desc="_get_cached_devices_for_user",
+        )
+        defer.returnValue({
+            device["device_id"]: db_to_json(device["content"])
+            for device in devices
+        })
+
+    def get_devices_with_keys_by_user(self, user_id):
+        """Get all devices (with any device keys) for a user
+
+        Returns:
+            (stream_id, devices)
+        """
+        return self.runInteraction(
+            "get_devices_with_keys_by_user",
+            self._get_devices_with_keys_by_user_txn, user_id,
+        )
+
+    def _get_devices_with_keys_by_user_txn(self, txn, user_id):
+        now_stream_id = self._device_list_id_gen.get_current_token()
+
+        devices = self._get_e2e_device_keys_txn(
+            txn, [(user_id, None)], include_all_devices=True
+        )
+
+        if devices:
+            user_devices = devices[user_id]
+            results = []
+            for device_id, device in iteritems(user_devices):
+                result = {
+                    "device_id": device_id,
+                }
+
+                key_json = device.get("key_json", None)
+                if key_json:
+                    result["keys"] = db_to_json(key_json)
+                device_display_name = device.get("device_display_name", None)
+                if device_display_name:
+                    result["device_display_name"] = device_display_name
+
+                results.append(result)
+
+            return now_stream_id, results
+
+        return now_stream_id, []
+
+    @defer.inlineCallbacks
+    def get_user_whose_devices_changed(self, from_key):
+        """Get set of users whose devices have changed since `from_key`.
+        """
+        from_key = int(from_key)
+        changed = self._device_list_stream_cache.get_all_entities_changed(from_key)
+        if changed is not None:
+            defer.returnValue(set(changed))
+
+        sql = """
+            SELECT DISTINCT user_id FROM device_lists_stream WHERE stream_id > ?
+        """
+        rows = yield self._execute("get_user_whose_devices_changed", None, sql, from_key)
+        defer.returnValue(set(row[0] for row in rows))
+
+    def get_all_device_list_changes_for_remotes(self, from_key, to_key):
+        """Return a list of `(stream_id, user_id, destination)` which is the
+        combined list of changes to devices, and which destinations need to be
+        poked. `destination` may be None if no destinations need to be poked.
+        """
+        # We do a group by here as there can be a large number of duplicate
+        # entries, since we throw away device IDs.
+        sql = """
+            SELECT MAX(stream_id) AS stream_id, user_id, destination
+            FROM device_lists_stream
+            LEFT JOIN device_lists_outbound_pokes USING (stream_id, user_id, device_id)
+            WHERE ? < stream_id AND stream_id <= ?
+            GROUP BY user_id, destination
+        """
+        return self._execute(
+            "get_all_device_list_changes_for_remotes", None,
+            sql, from_key, to_key
+        )
+
+    @cached(max_entries=10000)
+    def get_device_list_last_stream_id_for_remote(self, user_id):
+        """Get the last stream_id we got for a user. May be None if we haven't
+        got any information for them.
+        """
+        return self._simple_select_one_onecol(
+            table="device_lists_remote_extremeties",
+            keyvalues={"user_id": user_id},
+            retcol="stream_id",
+            desc="get_device_list_last_stream_id_for_remote",
+            allow_none=True,
+        )
+
+    @cachedList(cached_method_name="get_device_list_last_stream_id_for_remote",
+                list_name="user_ids", inlineCallbacks=True)
+    def get_device_list_last_stream_id_for_remotes(self, user_ids):
+        rows = yield self._simple_select_many_batch(
+            table="device_lists_remote_extremeties",
+            column="user_id",
+            iterable=user_ids,
+            retcols=("user_id", "stream_id",),
+            desc="get_device_list_last_stream_id_for_remotes",
+        )
+
+        results = {user_id: None for user_id in user_ids}
+        results.update({
+            row["user_id"]: row["stream_id"] for row in rows
+        })
+
+        defer.returnValue(results)
+
+
+class DeviceStore(DeviceWorkerStore, BackgroundUpdateStore):
     def __init__(self, db_conn, hs):
         super(DeviceStore, self).__init__(db_conn, hs)
 
@@ -121,24 +456,6 @@ class DeviceStore(BackgroundUpdateStore):
                          initial_device_display_name, e)
             raise StoreError(500, "Problem storing device.")
 
-    def get_device(self, user_id, device_id):
-        """Retrieve a device.
-
-        Args:
-            user_id (str): The ID of the user which owns the device
-            device_id (str): The ID of the device to retrieve
-        Returns:
-            defer.Deferred for a dict containing the device information
-        Raises:
-            StoreError: if the device is not found
-        """
-        return self._simple_select_one(
-            table="devices",
-            keyvalues={"user_id": user_id, "device_id": device_id},
-            retcols=("user_id", "device_id", "display_name"),
-            desc="get_device",
-        )
-
     @defer.inlineCallbacks
     def delete_device(self, user_id, device_id):
         """Delete a device.
@@ -203,57 +520,6 @@ class DeviceStore(BackgroundUpdateStore):
         )
 
     @defer.inlineCallbacks
-    def get_devices_by_user(self, user_id):
-        """Retrieve all of a user's registered devices.
-
-        Args:
-            user_id (str):
-        Returns:
-            defer.Deferred: resolves to a dict from device_id to a dict
-            containing "device_id", "user_id" and "display_name" for each
-            device.
-        """
-        devices = yield self._simple_select_list(
-            table="devices",
-            keyvalues={"user_id": user_id},
-            retcols=("user_id", "device_id", "display_name"),
-            desc="get_devices_by_user"
-        )
-
-        defer.returnValue({d["device_id"]: d for d in devices})
-
-    @cached(max_entries=10000)
-    def get_device_list_last_stream_id_for_remote(self, user_id):
-        """Get the last stream_id we got for a user. May be None if we haven't
-        got any information for them.
-        """
-        return self._simple_select_one_onecol(
-            table="device_lists_remote_extremeties",
-            keyvalues={"user_id": user_id},
-            retcol="stream_id",
-            desc="get_device_list_remote_extremity",
-            allow_none=True,
-        )
-
-    @cachedList(cached_method_name="get_device_list_last_stream_id_for_remote",
-                list_name="user_ids", inlineCallbacks=True)
-    def get_device_list_last_stream_id_for_remotes(self, user_ids):
-        rows = yield self._simple_select_many_batch(
-            table="device_lists_remote_extremeties",
-            column="user_id",
-            iterable=user_ids,
-            retcols=("user_id", "stream_id",),
-            desc="get_user_devices_from_cache",
-        )
-
-        results = {user_id: None for user_id in user_ids}
-        results.update({
-            row["user_id"]: row["stream_id"] for row in rows
-        })
-
-        defer.returnValue(results)
-
-    @defer.inlineCallbacks
     def mark_remote_user_device_list_as_unsubscribed(self, user_id):
         """Mark that we no longer track device lists for remote user.
         """
@@ -405,268 +671,6 @@ class DeviceStore(BackgroundUpdateStore):
             lock=False,
         )
 
-    def get_devices_by_remote(self, destination, from_stream_id):
-        """Get stream of updates to send to remote servers
-
-        Returns:
-            (int, list[dict]): current stream id and list of updates
-        """
-        now_stream_id = self._device_list_id_gen.get_current_token()
-
-        has_changed = self._device_list_federation_stream_cache.has_entity_changed(
-            destination, int(from_stream_id)
-        )
-        if not has_changed:
-            return (now_stream_id, [])
-
-        return self.runInteraction(
-            "get_devices_by_remote", self._get_devices_by_remote_txn,
-            destination, from_stream_id, now_stream_id,
-        )
-
-    def _get_devices_by_remote_txn(self, txn, destination, from_stream_id,
-                                   now_stream_id):
-        sql = """
-            SELECT user_id, device_id, max(stream_id) FROM device_lists_outbound_pokes
-            WHERE destination = ? AND ? < stream_id AND stream_id <= ? AND sent = ?
-            GROUP BY user_id, device_id
-            LIMIT 20
-        """
-        txn.execute(
-            sql, (destination, from_stream_id, now_stream_id, False)
-        )
-
-        # maps (user_id, device_id) -> stream_id
-        query_map = {(r[0], r[1]): r[2] for r in txn}
-        if not query_map:
-            return (now_stream_id, [])
-
-        if len(query_map) >= 20:
-            now_stream_id = max(stream_id for stream_id in itervalues(query_map))
-
-        devices = self._get_e2e_device_keys_txn(
-            txn, query_map.keys(), include_all_devices=True, include_deleted_devices=True
-        )
-
-        prev_sent_id_sql = """
-            SELECT coalesce(max(stream_id), 0) as stream_id
-            FROM device_lists_outbound_last_success
-            WHERE destination = ? AND user_id = ? AND stream_id <= ?
-        """
-
-        results = []
-        for user_id, user_devices in iteritems(devices):
-            # The prev_id for the first row is always the last row before
-            # `from_stream_id`
-            txn.execute(prev_sent_id_sql, (destination, user_id, from_stream_id))
-            rows = txn.fetchall()
-            prev_id = rows[0][0]
-            for device_id, device in iteritems(user_devices):
-                stream_id = query_map[(user_id, device_id)]
-                result = {
-                    "user_id": user_id,
-                    "device_id": device_id,
-                    "prev_id": [prev_id] if prev_id else [],
-                    "stream_id": stream_id,
-                }
-
-                prev_id = stream_id
-
-                if device is not None:
-                    key_json = device.get("key_json", None)
-                    if key_json:
-                        result["keys"] = db_to_json(key_json)
-                    device_display_name = device.get("device_display_name", None)
-                    if device_display_name:
-                        result["device_display_name"] = device_display_name
-                else:
-                    result["deleted"] = True
-
-                results.append(result)
-
-        return (now_stream_id, results)
-
-    @defer.inlineCallbacks
-    def get_user_devices_from_cache(self, query_list):
-        """Get the devices (and keys if any) for remote users from the cache.
-
-        Args:
-            query_list(list): List of (user_id, device_ids), if device_ids is
-                falsey then return all device ids for that user.
-
-        Returns:
-            (user_ids_not_in_cache, results_map), where user_ids_not_in_cache is
-            a set of user_ids and results_map is a mapping of
-            user_id -> device_id -> device_info
-        """
-        user_ids = set(user_id for user_id, _ in query_list)
-        user_map = yield self.get_device_list_last_stream_id_for_remotes(list(user_ids))
-        user_ids_in_cache = set(
-            user_id for user_id, stream_id in user_map.items() if stream_id
-        )
-        user_ids_not_in_cache = user_ids - user_ids_in_cache
-
-        results = {}
-        for user_id, device_id in query_list:
-            if user_id not in user_ids_in_cache:
-                continue
-
-            if device_id:
-                device = yield self._get_cached_user_device(user_id, device_id)
-                results.setdefault(user_id, {})[device_id] = device
-            else:
-                results[user_id] = yield self._get_cached_devices_for_user(user_id)
-
-        defer.returnValue((user_ids_not_in_cache, results))
-
-    @cachedInlineCallbacks(num_args=2, tree=True)
-    def _get_cached_user_device(self, user_id, device_id):
-        content = yield self._simple_select_one_onecol(
-            table="device_lists_remote_cache",
-            keyvalues={
-                "user_id": user_id,
-                "device_id": device_id,
-            },
-            retcol="content",
-            desc="_get_cached_user_device",
-        )
-        defer.returnValue(db_to_json(content))
-
-    @cachedInlineCallbacks()
-    def _get_cached_devices_for_user(self, user_id):
-        devices = yield self._simple_select_list(
-            table="device_lists_remote_cache",
-            keyvalues={
-                "user_id": user_id,
-            },
-            retcols=("device_id", "content"),
-            desc="_get_cached_devices_for_user",
-        )
-        defer.returnValue({
-            device["device_id"]: db_to_json(device["content"])
-            for device in devices
-        })
-
-    def get_devices_with_keys_by_user(self, user_id):
-        """Get all devices (with any device keys) for a user
-
-        Returns:
-            (stream_id, devices)
-        """
-        return self.runInteraction(
-            "get_devices_with_keys_by_user",
-            self._get_devices_with_keys_by_user_txn, user_id,
-        )
-
-    def _get_devices_with_keys_by_user_txn(self, txn, user_id):
-        now_stream_id = self._device_list_id_gen.get_current_token()
-
-        devices = self._get_e2e_device_keys_txn(
-            txn, [(user_id, None)], include_all_devices=True
-        )
-
-        if devices:
-            user_devices = devices[user_id]
-            results = []
-            for device_id, device in iteritems(user_devices):
-                result = {
-                    "device_id": device_id,
-                }
-
-                key_json = device.get("key_json", None)
-                if key_json:
-                    result["keys"] = db_to_json(key_json)
-                device_display_name = device.get("device_display_name", None)
-                if device_display_name:
-                    result["device_display_name"] = device_display_name
-
-                results.append(result)
-
-            return now_stream_id, results
-
-        return now_stream_id, []
-
-    def mark_as_sent_devices_by_remote(self, destination, stream_id):
-        """Mark that updates have successfully been sent to the destination.
-        """
-        return self.runInteraction(
-            "mark_as_sent_devices_by_remote", self._mark_as_sent_devices_by_remote_txn,
-            destination, stream_id,
-        )
-
-    def _mark_as_sent_devices_by_remote_txn(self, txn, destination, stream_id):
-        # We update the device_lists_outbound_last_success with the successfully
-        # poked users. We do the join to see which users need to be inserted and
-        # which updated.
-        sql = """
-            SELECT user_id, coalesce(max(o.stream_id), 0), (max(s.stream_id) IS NOT NULL)
-            FROM device_lists_outbound_pokes as o
-            LEFT JOIN device_lists_outbound_last_success as s
-                USING (destination, user_id)
-            WHERE destination = ? AND o.stream_id <= ?
-            GROUP BY user_id
-        """
-        txn.execute(sql, (destination, stream_id,))
-        rows = txn.fetchall()
-
-        sql = """
-            UPDATE device_lists_outbound_last_success
-            SET stream_id = ?
-            WHERE destination = ? AND user_id = ?
-        """
-        txn.executemany(
-            sql, ((row[1], destination, row[0],) for row in rows if row[2])
-        )
-
-        sql = """
-            INSERT INTO device_lists_outbound_last_success
-            (destination, user_id, stream_id) VALUES (?, ?, ?)
-        """
-        txn.executemany(
-            sql, ((destination, row[0], row[1],) for row in rows if not row[2])
-        )
-
-        # Delete all sent outbound pokes
-        sql = """
-            DELETE FROM device_lists_outbound_pokes
-            WHERE destination = ? AND stream_id <= ?
-        """
-        txn.execute(sql, (destination, stream_id,))
-
-    @defer.inlineCallbacks
-    def get_user_whose_devices_changed(self, from_key):
-        """Get set of users whose devices have changed since `from_key`.
-        """
-        from_key = int(from_key)
-        changed = self._device_list_stream_cache.get_all_entities_changed(from_key)
-        if changed is not None:
-            defer.returnValue(set(changed))
-
-        sql = """
-            SELECT DISTINCT user_id FROM device_lists_stream WHERE stream_id > ?
-        """
-        rows = yield self._execute("get_user_whose_devices_changed", None, sql, from_key)
-        defer.returnValue(set(row[0] for row in rows))
-
-    def get_all_device_list_changes_for_remotes(self, from_key, to_key):
-        """Return a list of `(stream_id, user_id, destination)` which is the
-        combined list of changes to devices, and which destinations need to be
-        poked. `destination` may be None if no destinations need to be poked.
-        """
-        # We do a group by here as there can be a large number of duplicate
-        # entries, since we throw away device IDs.
-        sql = """
-            SELECT MAX(stream_id) AS stream_id, user_id, destination
-            FROM device_lists_stream
-            LEFT JOIN device_lists_outbound_pokes USING (stream_id, user_id, device_id)
-            WHERE ? < stream_id AND stream_id <= ?
-            GROUP BY user_id, destination
-        """
-        return self._execute(
-            "get_all_device_list_changes_for_remotes", None,
-            sql, from_key, to_key
-        )
-
     @defer.inlineCallbacks
     def add_device_change_to_streams(self, user_id, device_ids, hosts):
         """Persist that a user's devices have been updated, and which hosts
@@ -732,9 +736,6 @@ class DeviceStore(BackgroundUpdateStore):
             ]
         )
 
-    def get_device_stream_token(self):
-        return self._device_list_id_gen.get_current_token()
-
     def _prune_old_outbound_device_pokes(self):
         """Delete old entries out of the device_lists_outbound_pokes to ensure
         that we don't fill up due to dead servers. We keep one entry per
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index 2a0f6cfca9..e381e472a2 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -23,49 +23,7 @@ from synapse.util.caches.descriptors import cached
 from ._base import SQLBaseStore, db_to_json
 
 
-class EndToEndKeyStore(SQLBaseStore):
-    def set_e2e_device_keys(self, user_id, device_id, time_now, device_keys):
-        """Stores device keys for a device. Returns whether there was a change
-        or the keys were already in the database.
-        """
-        def _set_e2e_device_keys_txn(txn):
-            old_key_json = self._simple_select_one_onecol_txn(
-                txn,
-                table="e2e_device_keys_json",
-                keyvalues={
-                    "user_id": user_id,
-                    "device_id": device_id,
-                },
-                retcol="key_json",
-                allow_none=True,
-            )
-
-            # In py3 we need old_key_json to match new_key_json type. The DB
-            # returns unicode while encode_canonical_json returns bytes.
-            new_key_json = encode_canonical_json(device_keys).decode("utf-8")
-
-            if old_key_json == new_key_json:
-                return False
-
-            self._simple_upsert_txn(
-                txn,
-                table="e2e_device_keys_json",
-                keyvalues={
-                    "user_id": user_id,
-                    "device_id": device_id,
-                },
-                values={
-                    "ts_added_ms": time_now,
-                    "key_json": new_key_json,
-                }
-            )
-
-            return True
-
-        return self.runInteraction(
-            "set_e2e_device_keys", _set_e2e_device_keys_txn
-        )
-
+class EndToEndKeyWorkerStore(SQLBaseStore):
     @defer.inlineCallbacks
     def get_e2e_device_keys(
         self, query_list, include_all_devices=False,
@@ -238,6 +196,50 @@ class EndToEndKeyStore(SQLBaseStore):
             "count_e2e_one_time_keys", _count_e2e_one_time_keys
         )
 
+
+class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
+    def set_e2e_device_keys(self, user_id, device_id, time_now, device_keys):
+        """Stores device keys for a device. Returns whether there was a change
+        or the keys were already in the database.
+        """
+        def _set_e2e_device_keys_txn(txn):
+            old_key_json = self._simple_select_one_onecol_txn(
+                txn,
+                table="e2e_device_keys_json",
+                keyvalues={
+                    "user_id": user_id,
+                    "device_id": device_id,
+                },
+                retcol="key_json",
+                allow_none=True,
+            )
+
+            # In py3 we need old_key_json to match new_key_json type. The DB
+            # returns unicode while encode_canonical_json returns bytes.
+            new_key_json = encode_canonical_json(device_keys).decode("utf-8")
+
+            if old_key_json == new_key_json:
+                return False
+
+            self._simple_upsert_txn(
+                txn,
+                table="e2e_device_keys_json",
+                keyvalues={
+                    "user_id": user_id,
+                    "device_id": device_id,
+                },
+                values={
+                    "ts_added_ms": time_now,
+                    "key_json": new_key_json,
+                }
+            )
+
+            return True
+
+        return self.runInteraction(
+            "set_e2e_device_keys", _set_e2e_device_keys_txn
+        )
+
     def claim_e2e_one_time_keys(self, query_list):
         """Take a list of one time keys out of the database"""
         def _claim_e2e_one_time_keys(txn):