Merge pull request #5946 from matrix-org/rei/rss_inc8 github/rei/rss_target rei/rss_target

Separated Statistics [8/7ish EOF]

5 files changed, 1132 insertions, 23 deletions

diff --git a/docs/room_and_user_statistics.md b/docs/room_and_user_statistics.md
new file mode 100644
index 0000000000..5514d36cfb
--- /dev/null
+++ b/docs/room_and_user_statistics.md
@@ -0,0 +1,136 @@
+Room and User Statistics
+========================
+
+Synapse maintains room and user statistics (as well as a cache of room state),
+in various tables.
+
+These can be used for administrative purposes but are also used when generating
+the public room directory. If these tables get stale or out of sync (possibly
+after database corruption), you may wish to regenerate them.
+
+
+# Synapse Administrator Documentation
+
+## Various SQL scripts that you may find useful
+
+### Delete stats, including historical stats
+
+```sql
+DELETE FROM room_stats_current;
+DELETE FROM room_stats_historical;
+DELETE FROM user_stats_current;
+DELETE FROM user_stats_historical;
+```
+
+### Regenerate stats (all subjects)
+
+```sql
+BEGIN;
+    DELETE FROM stats_incremental_position;
+    INSERT INTO stats_incremental_position (
+        state_delta_stream_id,
+        total_events_min_stream_ordering,
+        total_events_max_stream_ordering,
+        is_background_contract
+    ) VALUES (NULL, NULL, NULL, FALSE), (NULL, NULL, NULL, TRUE);
+COMMIT;
+
+DELETE FROM room_stats_current;
+DELETE FROM user_stats_current;
+```
+
+then follow the steps below for **'Regenerate stats (missing subjects only)'**
+
+### Regenerate stats (missing subjects only)
+
+```sql
+-- Set up staging tables
+-- we depend on current_state_events_membership because this is used
+-- in our counting.
+INSERT INTO background_updates (update_name, progress_json) VALUES
+    ('populate_stats_prepare', '{}', 'current_state_events_membership');
+
+-- Run through each room and update stats
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_stats_process_rooms', '{}', 'populate_stats_prepare');
+
+-- Run through each user and update stats.
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_stats_process_users', '{}', 'populate_stats_process_rooms');
+
+-- Clean up staging tables
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_stats_cleanup', '{}', 'populate_stats_process_users');
+```
+
+then **restart Synapse**.
+
+
+# Synapse Developer Documentation
+
+## High-Level Concepts
+
+### Definitions
+
+* **subject**: Something we are tracking stats about – currently a room or user.
+* **current row**: An entry for a subject in the appropriate current statistics
+    table. Each subject can have only one.
+* **historical row**: An entry for a subject in the appropriate historical
+    statistics table. Each subject can have any number of these.
+
+### Overview
+
+Stats are maintained as time series. There are two kinds of column:
+
+* absolute columns – where the value is correct for the time given by `end_ts`
+    in the stats row. (Imagine a line graph for these values)
+    * They can also be thought of as 'gauges' in Prometheus, if you are familiar.
+* per-slice columns – where the value corresponds to how many of the occurrences
+    occurred within the time slice given by `(end_ts − bucket_size)…end_ts`
+    or `start_ts…end_ts`. (Imagine a histogram for these values)
+
+Currently, only absolute columns are in use.
+
+Stats are maintained in two tables (for each type): current and historical.
+
+Current stats correspond to the present values. Each subject can only have one
+entry.
+
+Historical stats correspond to values in the past. Subjects may have multiple
+entries.
+
+## Concepts around the management of stats
+
+### current rows
+
+Current rows contain the most up-to-date statistics for a room.
+They only contain absolute columns
+
+#### incomplete current rows
+
+There are also **incomplete** current rows, which are current rows that do not
+contain a full count yet – this is because they are waiting for the regeneration
+process to give them an initial count. Incomplete current rows DO NOT contain
+correct and up-to-date values. As such, *incomplete rows are not old-collected*.
+Instead, old incomplete rows will be extended so they are no longer old.
+
+### historical rows
+
+Historical rows can always be considered to be valid for the time slice and
+end time specified. (This, of course, assumes a lack of defects in the code
+to track the statistics, and assumes integrity of the database).
+
+Even still, there are two considerations that we may need to bear in mind:
+
+* historical rows will not exist for every time slice – they will be omitted
+    if there were no changes. In this case, the following assumptions can be
+    made to interpolate/recreate missing rows:
+    - absolute fields have the same values as in the preceding row
+    - per-slice fields are zero (`0`)
+* historical rows will not be retained forever – rows older than a configurable
+    time will be purged.
+
+#### purge
+
+The purging of historical rows is not yet implemented.
+
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index f44adfc07b..e849c38b85 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -98,15 +98,16 @@ class StatsHandler(StateDeltasHandler):
                     self.pos["state_delta_stream_id"]
                 )
 
-                logger.debug("Handling %d state deltas", len(deltas))
-                yield self._handle_deltas(deltas)
+                if deltas:
+                    logger.debug("Handling %d state deltas", len(deltas))
+                    yield self._handle_deltas(deltas)
 
-                self.pos["state_delta_stream_id"] = deltas[-1]["stream_id"]
-                yield self.store.update_stats_positions(self.pos)
+                    self.pos["state_delta_stream_id"] = deltas[-1]["stream_id"]
+                    yield self.store.update_stats_positions(self.pos)
 
-                event_processing_positions.labels("stats").set(
-                    self.pos["state_delta_stream_id"]
-                )
+                    event_processing_positions.labels("stats").set(
+                        self.pos["state_delta_stream_id"]
+                    )
 
             # Then count deltas for total_events and total_event_bytes.
             with Measure(self.clock, "stats_total_events_and_bytes"):
@@ -129,7 +130,6 @@ class StatsHandler(StateDeltasHandler):
             event_id = delta["event_id"]
             stream_id = delta["stream_id"]
             prev_event_id = delta["prev_event_id"]
-            stream_pos = delta["stream_id"]
 
             logger.debug("Handling: %r %r, %s", typ, state_key, event_id)
 
@@ -158,12 +158,9 @@ class StatsHandler(StateDeltasHandler):
                 if event:
                     event_content = event.content or {}
 
-            # We use stream_pos here rather than fetch by event_id as event_id
-            # may be None
-            stream_timestamp = yield self.store.get_received_ts_by_stream_pos(
-                stream_pos
-            )
-            stream_timestamp = int(stream_timestamp)
+            # We can't afford for this time to stray into the past, so we count
+            # it as now.
+            stream_timestamp = int(self.clock.time_msec())
 
             # All the values in this dict are deltas (RELATIVE changes)
             room_stats_delta = {}
@@ -261,7 +258,7 @@ class StatsHandler(StateDeltasHandler):
                 is_newly_created = True
 
             elif typ == EventTypes.JoinRules:
-                old_room_state = yield self.store.get_room_state(room_id)
+                old_room_state = yield self.store.get_room_stats_state(room_id)
                 yield self.store.update_room_state(
                     room_id, {"join_rules": event_content.get("join_rule")}
                 )
@@ -282,7 +279,7 @@ class StatsHandler(StateDeltasHandler):
                         )
 
             elif typ == EventTypes.RoomHistoryVisibility:
-                old_room_state = yield self.store.get_room_state(room_id)
+                old_room_state = yield self.store.get_room_stats_state(room_id)
                 yield self.store.update_room_state(
                     room_id,
                     {"history_visibility": event_content.get("history_visibility")},
diff --git a/synapse/storage/stats.py b/synapse/storage/stats.py
index 24f739a017..f20d8ba8a4 100644
--- a/synapse/storage/stats.py
+++ b/synapse/storage/stats.py
@@ -661,6 +661,79 @@ class StatsStore(StateDeltasStore):
             desc="update_room_state",
         )
 
+    def get_statistics_for_subject(self, stats_type, stats_id, start, size=100):
+        """
+        Get statistics for a given subject.
+
+        Args:
+            stats_type (str): The type of subject
+            stats_id (str): The ID of the subject (e.g. room_id or user_id)
+            start (int): Pagination start. Number of entries, not timestamp.
+            size (int): How many entries to return.
+
+        Returns:
+            Deferred[list[dict]], where the dict has the keys of
+            ABSOLUTE_STATS_FIELDS[stats_type],  and "bucket_size" and "end_ts".
+        """
+        return self.runInteraction(
+            "get_statistics_for_subject",
+            self._get_statistics_for_subject_txn,
+            stats_type,
+            stats_id,
+            start,
+            size,
+        )
+
+    def _get_statistics_for_subject_txn(
+        self, txn, stats_type, stats_id, start, size=100
+    ):
+        """
+        Transaction-bound version of L{get_statistics_for_subject}.
+        """
+
+        table, id_col = TYPE_TO_TABLE[stats_type]
+        selected_columns = list(
+            ABSOLUTE_STATS_FIELDS[stats_type] + PER_SLICE_FIELDS[stats_type]
+        )
+
+        slice_list = self._simple_select_list_paginate_txn(
+            txn,
+            table + "_historical",
+            {id_col: stats_id},
+            "end_ts",
+            start,
+            size,
+            retcols=selected_columns + ["bucket_size", "end_ts"],
+            order_direction="DESC",
+        )
+
+        return slice_list
+
+    def get_room_stats_state(self, room_id):
+        """
+        Returns the current room_stats_state for a room.
+
+        Args:
+            room_id (str): The ID of the room to return state for.
+
+        Returns (dict):
+            Dictionary containing these keys:
+                "name", "topic", "canonical_alias", "avatar", "join_rules",
+                "history_visibility"
+        """
+        return self._simple_select_one(
+            "room_stats_state",
+            {"room_id": room_id},
+            retcols=(
+                "name",
+                "topic",
+                "canonical_alias",
+                "avatar",
+                "join_rules",
+                "history_visibility",
+            ),
+        )
+
     @cached()
     def get_earliest_token_for_stats(self, stats_type, id):
         """
@@ -948,10 +1021,11 @@ class StatsStore(StateDeltasStore):
             src_row = self._simple_select_one_txn(
                 txn, src_table, keyvalues, copy_columns
             )
+            all_dest_keyvalues = {**keyvalues, **extra_dst_keyvalues}
             dest_current_row = self._simple_select_one_txn(
                 txn,
                 into_table,
-                keyvalues,
+                keyvalues=all_dest_keyvalues,
                 retcols=list(chain(additive_relatives.keys(), copy_columns)),
                 allow_none=True,
             )
@@ -968,7 +1042,7 @@ class StatsStore(StateDeltasStore):
             else:
                 for (key, val) in additive_relatives.items():
                     src_row[key] = dest_current_row[key] + val
-                self._simple_update_txn(txn, into_table, keyvalues, src_row)
+                self._simple_update_txn(txn, into_table, all_dest_keyvalues, src_row)
 
     def incremental_update_room_total_events_and_bytes(self, in_positions):
         """
@@ -1059,14 +1133,14 @@ class StatsStore(StateDeltasStore):
             new_bytes_expression = "LENGTH(CAST(json AS BLOB))"
 
         sql = """
-            SELECT room_id, COUNT(*) AS new_events, SUM(%s) AS new_bytes
+            SELECT events.room_id, COUNT(*) AS new_events, SUM(%s) AS new_bytes
             FROM events INNER JOIN event_json USING (event_id)
             WHERE ? %s stream_ordering AND stream_ordering %s ?
-            GROUP BY room_id
+            GROUP BY events.room_id
         """ % (
+            new_bytes_expression,
             low_comparator,
             high_comparator,
-            new_bytes_expression,
         )
 
         txn.execute(sql, (low_pos, high_pos))
diff --git a/tests/handlers/test_stats.py b/tests/handlers/test_stats.py
new file mode 100644
index 0000000000..698cb1b418
--- /dev/null
+++ b/tests/handlers/test_stats.py
@@ -0,0 +1,898 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector Ltd
+#
+# 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 mock import Mock
+
+from twisted.internet import defer
+
+from synapse import storage
+from synapse.api.constants import EventTypes, Membership
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+
+from tests import unittest
+
+# The expected number of state events in a fresh public room.
+EXPT_NUM_STATE_EVTS_IN_FRESH_PUBLIC_ROOM = 5
+# The expected number of state events in a fresh private room.
+EXPT_NUM_STATE_EVTS_IN_FRESH_PRIVATE_ROOM = 6
+
+
+class StatsRoomTests(unittest.HomeserverTestCase):
+
+    servlets = [
+        admin.register_servlets_for_client_rest_resource,
+        room.register_servlets,
+        login.register_servlets,
+    ]
+
+    def prepare(self, reactor, clock, hs):
+        self.store = hs.get_datastore()
+        self.handler = self.hs.get_stats_handler()
+
+    def _add_background_updates(self):
+        """
+        Add the background updates we need to run.
+        """
+        # Ugh, have to reset this flag
+        self.store._all_done = False
+
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {"update_name": "populate_stats_prepare", "progress_json": "{}"},
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_process_rooms",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_prepare",
+                },
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_process_users",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_process_rooms",
+                },
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_cleanup",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_process_users",
+                },
+            )
+        )
+
+    def get_all_room_state(self):
+        return self.store._simple_select_list(
+            "room_stats_state", None, retcols=("name", "topic", "canonical_alias")
+        )
+
+    def _get_current_stats(self, stats_type, stat_id):
+        table, id_col = storage.stats.TYPE_TO_TABLE[stats_type]
+
+        cols = (
+            ["completed_delta_stream_id"]
+            + list(storage.stats.ABSOLUTE_STATS_FIELDS[stats_type])
+            + list(storage.stats.PER_SLICE_FIELDS[stats_type])
+        )
+
+        return self.get_success(
+            self.store._simple_select_one(
+                table + "_current", {id_col: stat_id}, cols, allow_none=True
+            )
+        )
+
+    def _perform_background_initial_update(self):
+        # Do the initial population of the stats via the background update
+        self._add_background_updates()
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+    def test_initial_room(self):
+        """
+        The background updates will build the table from scratch.
+        """
+        r = self.get_success(self.get_all_room_state())
+        self.assertEqual(len(r), 0)
+
+        # Disable stats
+        self.hs.config.stats_enabled = False
+        self.handler.stats_enabled = False
+
+        u1 = self.register_user("u1", "pass")
+        u1_token = self.login("u1", "pass")
+
+        room_1 = self.helper.create_room_as(u1, tok=u1_token)
+        self.helper.send_state(
+            room_1, event_type="m.room.topic", body={"topic": "foo"}, tok=u1_token
+        )
+
+        # Stats disabled, shouldn't have done anything
+        r = self.get_success(self.get_all_room_state())
+        self.assertEqual(len(r), 0)
+
+        # Enable stats
+        self.hs.config.stats_enabled = True
+        self.handler.stats_enabled = True
+
+        # Do the initial population of the user directory via the background update
+        self._add_background_updates()
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        r = self.get_success(self.get_all_room_state())
+
+        self.assertEqual(len(r), 1)
+        self.assertEqual(r[0]["topic"], "foo")
+
+    def test_initial_earliest_token(self):
+        """
+        Ingestion via notify_new_event will ignore tokens that the background
+        update have already processed.
+        """
+
+        self.reactor.advance(86401)
+
+        self.hs.config.stats_enabled = False
+        self.handler.stats_enabled = False
+
+        u1 = self.register_user("u1", "pass")
+        u1_token = self.login("u1", "pass")
+
+        u2 = self.register_user("u2", "pass")
+        u2_token = self.login("u2", "pass")
+
+        u3 = self.register_user("u3", "pass")
+        u3_token = self.login("u3", "pass")
+
+        room_1 = self.helper.create_room_as(u1, tok=u1_token)
+        self.helper.send_state(
+            room_1, event_type="m.room.topic", body={"topic": "foo"}, tok=u1_token
+        )
+
+        # Begin the ingestion by creating the temp tables. This will also store
+        # the position that the deltas should begin at, once they take over.
+        self.hs.config.stats_enabled = True
+        self.handler.stats_enabled = True
+        self.store._all_done = False
+        self.get_success(self.store.update_stats_positions(None))
+
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {"update_name": "populate_stats_prepare", "progress_json": "{}"},
+            )
+        )
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        # Now, before the table is actually ingested, add some more events.
+        self.helper.invite(room=room_1, src=u1, targ=u2, tok=u1_token)
+        self.helper.join(room=room_1, user=u2, tok=u2_token)
+
+        # orig_delta_processor = self.store.
+
+        # Now do the initial ingestion.
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {"update_name": "populate_stats_process_rooms", "progress_json": "{}"},
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_cleanup",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_process_rooms",
+                },
+            )
+        )
+
+        self.store._all_done = False
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        self.reactor.advance(86401)
+
+        # Now add some more events, triggering ingestion. Because of the stream
+        # position being set to before the events sent in the middle, a simpler
+        # implementation would reprocess those events, and say there were four
+        # users, not three.
+        self.helper.invite(room=room_1, src=u1, targ=u3, tok=u1_token)
+        self.helper.join(room=room_1, user=u3, tok=u3_token)
+
+        # self.handler.notify_new_event()
+
+        # We need to let the delta processor advance…
+        self.pump(10 * 60)
+
+        # Get the slices! There should be two -- day 1, and day 2.
+        r = self.get_success(self.store.get_statistics_for_subject("room", room_1, 0))
+
+        self.assertEqual(len(r), 2)
+
+        # The oldest has 2 joined members
+        self.assertEqual(r[-1]["joined_members"], 2)
+
+        # The newest has 3
+        self.assertEqual(r[0]["joined_members"], 3)
+
+    def test_incorrect_state_transition(self):
+        """
+        If the state transition is not one of (JOIN, INVITE, LEAVE, BAN) to
+        (JOIN, INVITE, LEAVE, BAN), an error is raised.
+        """
+        events = {
+            "a1": {"membership": Membership.LEAVE},
+            "a2": {"membership": "not a real thing"},
+        }
+
+        def get_event(event_id, allow_none=True):
+            m = Mock()
+            m.content = events[event_id]
+            d = defer.Deferred()
+            self.reactor.callLater(0.0, d.callback, m)
+            return d
+
+        def get_received_ts(event_id):
+            return defer.succeed(1)
+
+        self.store.get_received_ts = get_received_ts
+        self.store.get_event = get_event
+
+        deltas = [
+            {
+                "type": EventTypes.Member,
+                "state_key": "some_user",
+                "room_id": "room",
+                "event_id": "a1",
+                "prev_event_id": "a2",
+                "stream_id": 60,
+            }
+        ]
+
+        f = self.get_failure(self.handler._handle_deltas(deltas), ValueError)
+        self.assertEqual(
+            f.value.args[0], "'not a real thing' is not a valid prev_membership"
+        )
+
+        # And the other way...
+        deltas = [
+            {
+                "type": EventTypes.Member,
+                "state_key": "some_user",
+                "room_id": "room",
+                "event_id": "a2",
+                "prev_event_id": "a1",
+                "stream_id": 100,
+            }
+        ]
+
+        f = self.get_failure(self.handler._handle_deltas(deltas), ValueError)
+        self.assertEqual(
+            f.value.args[0], "'not a real thing' is not a valid membership"
+        )
+
+    def test_redacted_prev_event(self):
+        """
+        If the prev_event does not exist, then it is assumed to be a LEAVE.
+        """
+        u1 = self.register_user("u1", "pass")
+        u1_token = self.login("u1", "pass")
+
+        room_1 = self.helper.create_room_as(u1, tok=u1_token)
+
+        # Do the initial population of the stats via the background update
+        self._add_background_updates()
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        events = {"a1": None, "a2": {"membership": Membership.JOIN}}
+
+        def get_event(event_id, allow_none=True):
+            if events.get(event_id):
+                m = Mock()
+                m.content = events[event_id]
+            else:
+                m = None
+            d = defer.Deferred()
+            self.reactor.callLater(0.0, d.callback, m)
+            return d
+
+        def get_received_ts(event_id):
+            return defer.succeed(1)
+
+        self.store.get_received_ts = get_received_ts
+        self.store.get_event = get_event
+
+        deltas = [
+            {
+                "type": EventTypes.Member,
+                "state_key": "some_user:test",
+                "room_id": room_1,
+                "event_id": "a2",
+                "prev_event_id": "a1",
+                "stream_id": 100,
+            }
+        ]
+
+        # Handle our fake deltas, which has a user going from LEAVE -> JOIN.
+        self.get_success(self.handler._handle_deltas(deltas))
+
+        # One delta, with two joined members -- the room creator, and our fake
+        # user.
+        r = self.get_success(self.store.get_statistics_for_subject("room", room_1, 0))
+        self.assertEqual(len(r), 1)
+        self.assertEqual(r[0]["joined_members"], 2)
+
+    def test_create_user(self):
+        """
+        When we create a user, it should have statistics already ready.
+        """
+
+        u1 = self.register_user("u1", "pass")
+
+        u1stats = self._get_current_stats("user", u1)
+
+        self.assertIsNotNone(u1stats)
+
+        # row is complete
+        self.assertIsNotNone(u1stats["completed_delta_stream_id"])
+
+        # not in any rooms by default
+        self.assertEqual(u1stats["public_rooms"], 0)
+        self.assertEqual(u1stats["private_rooms"], 0)
+
+    def test_create_room(self):
+        """
+        When we create a room, it should have statistics already ready.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+        r1stats = self._get_current_stats("room", r1)
+        r2 = self.helper.create_room_as(u1, tok=u1token, is_public=False)
+        r2stats = self._get_current_stats("room", r2)
+
+        self.assertIsNotNone(r1stats)
+        self.assertIsNotNone(r2stats)
+
+        # row is complete
+        self.assertIsNotNone(r1stats["completed_delta_stream_id"])
+        self.assertIsNotNone(r2stats["completed_delta_stream_id"])
+
+        # contains the default things you'd expect in a fresh room
+        self.assertEqual(
+            r1stats["total_events"],
+            EXPT_NUM_STATE_EVTS_IN_FRESH_PUBLIC_ROOM,
+            "Wrong number of total_events in new room's stats!"
+            " You may need to update this if more state events are added to"
+            " the room creation process.",
+        )
+        self.assertEqual(
+            r2stats["total_events"],
+            EXPT_NUM_STATE_EVTS_IN_FRESH_PRIVATE_ROOM,
+            "Wrong number of total_events in new room's stats!"
+            " You may need to update this if more state events are added to"
+            " the room creation process.",
+        )
+
+        self.assertEqual(
+            r1stats["current_state_events"], EXPT_NUM_STATE_EVTS_IN_FRESH_PUBLIC_ROOM
+        )
+        self.assertEqual(
+            r2stats["current_state_events"], EXPT_NUM_STATE_EVTS_IN_FRESH_PRIVATE_ROOM
+        )
+
+        self.assertEqual(r1stats["joined_members"], 1)
+        self.assertEqual(r1stats["invited_members"], 0)
+        self.assertEqual(r1stats["banned_members"], 0)
+
+        self.assertEqual(r2stats["joined_members"], 1)
+        self.assertEqual(r2stats["invited_members"], 0)
+        self.assertEqual(r2stats["banned_members"], 0)
+
+    def test_send_message_increments_total_events(self):
+        """
+        When we send a message, it increments total_events.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.send(r1, "hiss", tok=u1token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+
+    def test_send_state_event_nonoverwriting(self):
+        """
+        When we send a non-overwriting state event, it increments total_events AND current_state_events
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        self.helper.send_state(
+            r1, "cat.hissing", {"value": True}, tok=u1token, state_key="tabby"
+        )
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.send_state(
+            r1, "cat.hissing", {"value": False}, tok=u1token, state_key="moggy"
+        )
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            1,
+        )
+
+    def test_send_state_event_overwriting(self):
+        """
+        When we send an overwriting state event, it increments total_events ONLY
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        self.helper.send_state(
+            r1, "cat.hissing", {"value": True}, tok=u1token, state_key="tabby"
+        )
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.send_state(
+            r1, "cat.hissing", {"value": False}, tok=u1token, state_key="tabby"
+        )
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            0,
+        )
+
+    def test_join_first_time(self):
+        """
+        When a user joins a room for the first time, total_events, current_state_events and
+        joined_members should increase by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.join(r1, u2, tok=u2token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            1,
+        )
+        self.assertEqual(
+            r1stats_post["joined_members"] - r1stats_ante["joined_members"], 1
+        )
+
+    def test_join_after_leave(self):
+        """
+        When a user joins a room after being previously left, total_events and
+        joined_members should increase by exactly 1.
+        current_state_events should not increase.
+        left_members should decrease by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+
+        self.helper.join(r1, u2, tok=u2token)
+        self.helper.leave(r1, u2, tok=u2token)
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.join(r1, u2, tok=u2token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            0,
+        )
+        self.assertEqual(
+            r1stats_post["joined_members"] - r1stats_ante["joined_members"], +1
+        )
+        self.assertEqual(
+            r1stats_post["left_members"] - r1stats_ante["left_members"], -1
+        )
+
+    def test_invited(self):
+        """
+        When a user invites another user, current_state_events, total_events and
+        invited_members should increase by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.invite(r1, u1, u2, tok=u1token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            1,
+        )
+        self.assertEqual(
+            r1stats_post["invited_members"] - r1stats_ante["invited_members"], +1
+        )
+
+    def test_join_after_invite(self):
+        """
+        When a user joins a room after being invited, total_events and
+        joined_members should increase by exactly 1.
+        current_state_events should not increase.
+        invited_members should decrease by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+
+        self.helper.invite(r1, u1, u2, tok=u1token)
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.join(r1, u2, tok=u2token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            0,
+        )
+        self.assertEqual(
+            r1stats_post["joined_members"] - r1stats_ante["joined_members"], +1
+        )
+        self.assertEqual(
+            r1stats_post["invited_members"] - r1stats_ante["invited_members"], -1
+        )
+
+    def test_left(self):
+        """
+        When a user leaves a room after joining, total_events and
+        left_members should increase by exactly 1.
+        current_state_events should not increase.
+        joined_members should decrease by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+
+        self.helper.join(r1, u2, tok=u2token)
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.leave(r1, u2, tok=u2token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            0,
+        )
+        self.assertEqual(
+            r1stats_post["left_members"] - r1stats_ante["left_members"], +1
+        )
+        self.assertEqual(
+            r1stats_post["joined_members"] - r1stats_ante["joined_members"], -1
+        )
+
+    def test_banned(self):
+        """
+        When a user is banned from a room after joining, total_events and
+        left_members should increase by exactly 1.
+        current_state_events should not increase.
+        banned_members should decrease by exactly 1.
+        """
+
+        self._perform_background_initial_update()
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+
+        self.helper.join(r1, u2, tok=u2token)
+
+        r1stats_ante = self._get_current_stats("room", r1)
+
+        self.helper.change_membership(r1, u1, u2, "ban", tok=u1token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+
+        self.assertEqual(r1stats_post["total_events"] - r1stats_ante["total_events"], 1)
+        self.assertEqual(
+            r1stats_post["current_state_events"] - r1stats_ante["current_state_events"],
+            0,
+        )
+        self.assertEqual(
+            r1stats_post["banned_members"] - r1stats_ante["banned_members"], +1
+        )
+        self.assertEqual(
+            r1stats_post["joined_members"] - r1stats_ante["joined_members"], -1
+        )
+
+    def test_initial_background_update(self):
+        """
+        Test that statistics can be generated by the initial background update
+        handler.
+
+        This test also tests that stats rows are not created for new subjects
+        when stats are disabled. However, it may be desirable to change this
+        behaviour eventually to still keep current rows.
+        """
+
+        self.hs.config.stats_enabled = False
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token)
+
+        # test that these subjects, which were created during a time of disabled
+        # stats, do not have stats.
+        self.assertIsNone(self._get_current_stats("room", r1))
+        self.assertIsNone(self._get_current_stats("user", u1))
+
+        self.hs.config.stats_enabled = True
+
+        self._perform_background_initial_update()
+
+        r1stats = self._get_current_stats("room", r1)
+        u1stats = self._get_current_stats("user", u1)
+
+        self.assertIsNotNone(r1stats["completed_delta_stream_id"])
+        self.assertIsNotNone(u1stats["completed_delta_stream_id"])
+
+        self.assertEqual(r1stats["joined_members"], 1)
+        self.assertEqual(
+            r1stats["total_events"], EXPT_NUM_STATE_EVTS_IN_FRESH_PUBLIC_ROOM
+        )
+        self.assertEqual(
+            r1stats["current_state_events"], EXPT_NUM_STATE_EVTS_IN_FRESH_PUBLIC_ROOM
+        )
+
+        self.assertEqual(u1stats["public_rooms"], 1)
+
+    def test_incomplete_stats(self):
+        """
+        This tests that we track incomplete statistics.
+
+        We first test that incomplete stats are incrementally generated,
+        following the preparation of a background regen.
+
+        We then test that these incomplete rows are completed by the background
+        regen.
+        """
+
+        u1 = self.register_user("u1", "pass")
+        u1token = self.login("u1", "pass")
+        u2 = self.register_user("u2", "pass")
+        u2token = self.login("u2", "pass")
+        u3 = self.register_user("u3", "pass")
+        r1 = self.helper.create_room_as(u1, tok=u1token, is_public=False)
+
+        # preparation stage of the initial background update
+        # Ugh, have to reset this flag
+        self.store._all_done = False
+
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {"update_name": "populate_stats_prepare", "progress_json": "{}"},
+            )
+        )
+
+        self.get_success(
+            self.store._simple_delete(
+                "room_stats_current", {"1": 1}, "test_delete_stats"
+            )
+        )
+        self.get_success(
+            self.store._simple_delete(
+                "user_stats_current", {"1": 1}, "test_delete_stats"
+            )
+        )
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        r1stats_ante = self._get_current_stats("room", r1)
+        u1stats_ante = self._get_current_stats("user", u1)
+        u2stats_ante = self._get_current_stats("user", u2)
+
+        self.helper.invite(r1, u1, u2, tok=u1token)
+        self.helper.join(r1, u2, tok=u2token)
+        self.helper.invite(r1, u1, u3, tok=u1token)
+        self.helper.send(r1, "thou shalt yield", tok=u1token)
+
+        r1stats_post = self._get_current_stats("room", r1)
+        u1stats_post = self._get_current_stats("user", u1)
+        u2stats_post = self._get_current_stats("user", u2)
+
+        # now let the background update continue & finish
+
+        self.store._all_done = False
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_process_rooms",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_prepare",
+                },
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_process_users",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_process_rooms",
+                },
+            )
+        )
+        self.get_success(
+            self.store._simple_insert(
+                "background_updates",
+                {
+                    "update_name": "populate_stats_cleanup",
+                    "progress_json": "{}",
+                    "depends_on": "populate_stats_process_users",
+                },
+            )
+        )
+
+        while not self.get_success(self.store.has_completed_background_updates()):
+            self.get_success(self.store.do_next_background_update(100), by=0.1)
+
+        r1stats_complete = self._get_current_stats("room", r1)
+        u1stats_complete = self._get_current_stats("user", u1)
+        u2stats_complete = self._get_current_stats("user", u2)
+
+        # now we make our assertions
+
+        # first check that none of the stats rows were complete before
+        # the background update occurred.
+        self.assertIsNone(r1stats_ante["completed_delta_stream_id"])
+        self.assertIsNone(r1stats_post["completed_delta_stream_id"])
+        self.assertIsNone(u1stats_ante["completed_delta_stream_id"])
+        self.assertIsNone(u1stats_post["completed_delta_stream_id"])
+        self.assertIsNone(u2stats_ante["completed_delta_stream_id"])
+        self.assertIsNone(u2stats_post["completed_delta_stream_id"])
+
+        # check that _ante rows are all skeletons without any deltas applied
+        self.assertEqual(r1stats_ante["joined_members"], 0)
+        self.assertEqual(r1stats_ante["invited_members"], 0)
+        self.assertEqual(r1stats_ante["total_events"], 0)
+        self.assertEqual(r1stats_ante["current_state_events"], 0)
+
+        self.assertEqual(u1stats_ante["public_rooms"], 0)
+        self.assertEqual(u1stats_ante["private_rooms"], 0)
+        self.assertEqual(u2stats_ante["public_rooms"], 0)
+        self.assertEqual(u2stats_ante["private_rooms"], 0)
+
+        # check that _post rows have the expected deltas applied
+        self.assertEqual(r1stats_post["joined_members"], 1)
+        self.assertEqual(r1stats_post["invited_members"], 1)
+        self.assertEqual(r1stats_post["total_events"], 4)
+        self.assertEqual(r1stats_post["current_state_events"], 2)
+
+        self.assertEqual(u1stats_post["public_rooms"], 0)
+        self.assertEqual(u1stats_post["private_rooms"], 0)
+        self.assertEqual(u2stats_post["public_rooms"], 0)
+        self.assertEqual(u2stats_post["private_rooms"], 1)
+
+        # check that _complete rows are complete and correct
+        self.assertEqual(r1stats_complete["joined_members"], 2)
+        self.assertEqual(r1stats_complete["invited_members"], 1)
+        self.assertEqual(
+            r1stats_complete["total_events"],
+            4 + EXPT_NUM_STATE_EVTS_IN_FRESH_PRIVATE_ROOM,
+        )
+        self.assertEqual(
+            r1stats_complete["current_state_events"],
+            2 + EXPT_NUM_STATE_EVTS_IN_FRESH_PRIVATE_ROOM,
+        )
+
+        self.assertEqual(u1stats_complete["public_rooms"], 0)
+        self.assertEqual(u1stats_complete["private_rooms"], 1)
+        self.assertEqual(u2stats_complete["public_rooms"], 0)
+        self.assertEqual(u2stats_complete["private_rooms"], 1)
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index 9915367144..cdded88b7f 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -128,8 +128,12 @@ class RestHelper(object):
 
         return channel.json_body
 
-    def send_state(self, room_id, event_type, body, tok, expect_code=200):
-        path = "/_matrix/client/r0/rooms/%s/state/%s" % (room_id, event_type)
+    def send_state(self, room_id, event_type, body, tok, expect_code=200, state_key=""):
+        path = "/_matrix/client/r0/rooms/%s/state/%s/%s" % (
+            room_id,
+            event_type,
+            state_key,
+        )
         if tok:
             path = path + "?access_token=%s" % tok