Merge tag 'v0.33.5'

Features
--------

- Python 3.5 and 3.6 support is now in beta.
([\#3576](https://github.com/matrix-org/synapse/issues/3576))
- Implement `event_format` filter param in `/sync`
([\#3790](https://github.com/matrix-org/synapse/issues/3790))
- Add synapse_admin_mau:registered_reserved_users metric to expose
number of real reaserved users
([\#3846](https://github.com/matrix-org/synapse/issues/3846))

Bugfixes
--------

- Remove connection ID for replication prometheus metrics, as it creates
a large number of new series.
([\#3788](https://github.com/matrix-org/synapse/issues/3788))
- guest users should not be part of mau total
([\#3800](https://github.com/matrix-org/synapse/issues/3800))
- Bump dependency on pyopenssl 16.x, to avoid incompatibility with
recent Twisted.
([\#3804](https://github.com/matrix-org/synapse/issues/3804))
- Fix existing room tags not coming down sync when joining a room
([\#3810](https://github.com/matrix-org/synapse/issues/3810))
- Fix jwt import check
([\#3824](https://github.com/matrix-org/synapse/issues/3824))
- fix VOIP crashes under Python 3 (#3821)
([\#3835](https://github.com/matrix-org/synapse/issues/3835))
- Fix manhole so that it works with latest openssh clients
([\#3841](https://github.com/matrix-org/synapse/issues/3841))
- Fix outbound requests occasionally wedging, which can result in
federation breaking between servers.
([\#3845](https://github.com/matrix-org/synapse/issues/3845))
- Show heroes if room name/canonical alias has been deleted
([\#3851](https://github.com/matrix-org/synapse/issues/3851))
- Fix handling of redacted events from federation
([\#3859](https://github.com/matrix-org/synapse/issues/3859))
-  ([\#3874](https://github.com/matrix-org/synapse/issues/3874))
- Mitigate outbound federation randomly becoming wedged
([\#3875](https://github.com/matrix-org/synapse/issues/3875))

Internal Changes
----------------

- CircleCI tests now run on the potential merge of a PR.
([\#3704](https://github.com/matrix-org/synapse/issues/3704))
- http/ is now ported to Python 3.
([\#3771](https://github.com/matrix-org/synapse/issues/3771))
- Improve human readable error messages for threepid
registration/account update
([\#3789](https://github.com/matrix-org/synapse/issues/3789))
- Make /sync slightly faster by avoiding needless copies
([\#3795](https://github.com/matrix-org/synapse/issues/3795))
- handlers/ is now ported to Python 3.
([\#3803](https://github.com/matrix-org/synapse/issues/3803))
- Limit the number of PDUs/EDUs per federation transaction
([\#3805](https://github.com/matrix-org/synapse/issues/3805))
- Only start postgres instance for postgres tests on Travis CI
([\#3806](https://github.com/matrix-org/synapse/issues/3806))
- tests/ is now ported to Python 3.
([\#3808](https://github.com/matrix-org/synapse/issues/3808))
- crypto/ is now ported to Python 3.
([\#3822](https://github.com/matrix-org/synapse/issues/3822))
- rest/ is now ported to Python 3.
([\#3823](https://github.com/matrix-org/synapse/issues/3823))
- add some logging for the keyring queue
([\#3826](https://github.com/matrix-org/synapse/issues/3826))
- speed up lazy loading by 2-3x
([\#3827](https://github.com/matrix-org/synapse/issues/3827))
- Improved Dockerfile to remove build requirements after building
reducing the image size.
([\#3834](https://github.com/matrix-org/synapse/issues/3834))
- Disable lazy loading for incremental syncs for now
([\#3840](https://github.com/matrix-org/synapse/issues/3840))
- federation/ is now ported to Python 3.
([\#3847](https://github.com/matrix-org/synapse/issues/3847))
- Log when we retry outbound requests
([\#3853](https://github.com/matrix-org/synapse/issues/3853))
- Removed some excess logging messages.
([\#3855](https://github.com/matrix-org/synapse/issues/3855))
- Speed up purge history for rooms that have been previously purged
([\#3856](https://github.com/matrix-org/synapse/issues/3856))
- Refactor some HTTP timeout code.
([\#3857](https://github.com/matrix-org/synapse/issues/3857))
- Fix running merged builds on CircleCI
([\#3858](https://github.com/matrix-org/synapse/issues/3858))
- Fix typo in replication stream exception.
([\#3860](https://github.com/matrix-org/synapse/issues/3860))
- Add in flight real time metrics for Measure blocks
([\#3871](https://github.com/matrix-org/synapse/issues/3871))
- Disable buffering and automatic retrying in treq requests to prevent
timeouts. ([\#3872](https://github.com/matrix-org/synapse/issues/3872))
- mention jemalloc in the README
([\#3877](https://github.com/matrix-org/synapse/issues/3877))
- Remove unmaintained "nuke-room-from-db.sh" script
([\#3888](https://github.com/matrix-org/synapse/issues/3888))

1 files changed, 65 insertions, 0 deletions

diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py

index 9b4e6d6aa8..0707f9a86a 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -51,6 +51,12 @@ ProfileInfo = namedtuple(
     "ProfileInfo", ("avatar_url", "display_name")
 )
 
+# "members" points to a truncated list of (user_id, event_id) tuples for users of
+# a given membership type, suitable for use in calculating heroes for a room.
+# "count" points to the total numberr of users of a given membership type.
+MemberSummary = namedtuple(
+    "MemberSummary", ("members", "count")
+)
 
 _MEMBERSHIP_PROFILE_UPDATE_NAME = "room_membership_profile_update"
 
@@ -82,6 +88,65 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             return [to_ascii(r[0]) for r in txn]
         return self.runInteraction("get_users_in_room", f)
 
+    @cached(max_entries=100000)
+    def get_room_summary(self, room_id):
+        """ Get the details of a room roughly suitable for use by the room
+        summary extension to /sync. Useful when lazy loading room members.
+        Args:
+            room_id (str): The room ID to query
+        Returns:
+            Deferred[dict[str, MemberSummary]:
+                dict of membership states, pointing to a MemberSummary named tuple.
+        """
+
+        def _get_room_summary_txn(txn):
+            # first get counts.
+            # We do this all in one transaction to keep the cache small.
+            # FIXME: get rid of this when we have room_stats
+            sql = """
+                SELECT count(*), m.membership FROM room_memberships as m
+                 INNER JOIN current_state_events as c
+                 ON m.event_id = c.event_id
+                 AND m.room_id = c.room_id
+                 AND m.user_id = c.state_key
+                 WHERE c.type = 'm.room.member' AND c.room_id = ?
+                 GROUP BY m.membership
+            """
+
+            txn.execute(sql, (room_id,))
+            res = {}
+            for count, membership in txn:
+                summary = res.setdefault(to_ascii(membership), MemberSummary([], count))
+
+            # we order by membership and then fairly arbitrarily by event_id so
+            # heroes are consistent
+            sql = """
+                SELECT m.user_id, m.membership, m.event_id
+                FROM room_memberships as m
+                 INNER JOIN current_state_events as c
+                 ON m.event_id = c.event_id
+                 AND m.room_id = c.room_id
+                 AND m.user_id = c.state_key
+                 WHERE c.type = 'm.room.member' AND c.room_id = ?
+                 ORDER BY
+                    CASE m.membership WHEN ? THEN 1 WHEN ? THEN 2 ELSE 3 END ASC,
+                    m.event_id ASC
+                 LIMIT ?
+            """
+
+            # 6 is 5 (number of heroes) plus 1, in case one of them is the calling user.
+            txn.execute(sql, (room_id, Membership.JOIN, Membership.INVITE, 6))
+            for user_id, membership, event_id in txn:
+                summary = res[to_ascii(membership)]
+                # we will always have a summary for this membership type at this
+                # point given the summary currently contains the counts.
+                members = summary.members
+                members.append((to_ascii(user_id), to_ascii(event_id)))
+
+            return res
+
+        return self.runInteraction("get_room_summary", _get_room_summary_txn)
+
     @cached()
     def get_invited_rooms_for_user(self, user_id):
         """ Get all the rooms the user is invited to