Commit Graph

13 Commits

Author SHA1 Message Date
Eric Eastwood
fef2e792be
Fix historical messages backfilling in random order on remote homeservers (MSC2716) (#11114)
Fix https://github.com/matrix-org/synapse/issues/11091
Fix https://github.com/matrix-org/synapse/issues/10764 (side-stepping the issue because we no longer have to deal with `fake_prev_event_id`)

 1. Made the `/backfill` response return messages in `(depth, stream_ordering)` order (previously only sorted by `depth`)
    - Technically, it shouldn't really matter how `/backfill` returns things but I'm just trying to make the `stream_ordering` a little more consistent from the origin to the remote homeservers in order to get the order of messages from `/messages` consistent ([sorted by `(topological_ordering, stream_ordering)`](https://github.com/matrix-org/synapse/blob/develop/docs/development/room-dag-concepts.md#depth-and-stream-ordering)).
    - Even now that we return backfilled messages in order, it still doesn't guarantee the same `stream_ordering` (and more importantly the [`/messages` order](https://github.com/matrix-org/synapse/blob/develop/docs/development/room-dag-concepts.md#depth-and-stream-ordering)) on the other server. For example, if a room has a bunch of history imported and someone visits a permalink to a historical message back in time, their homeserver will skip over the historical messages in between and insert the permalink as the next message in the `stream_order` and totally throw off the sort.
       - This will be even more the case when we add the [MSC3030 jump to date API endpoint](https://github.com/matrix-org/matrix-doc/pull/3030) so the static archives can navigate and jump to a certain date.
       - We're solving this in the future by switching to [online topological ordering](https://github.com/matrix-org/gomatrixserverlib/issues/187) and [chunking](https://github.com/matrix-org/synapse/issues/3785) which by its nature will apply retroactively to fix any inconsistencies introduced by people permalinking
 2. As we're navigating `prev_events` to return in `/backfill`, we order by `depth` first (newest -> oldest) and now also tie-break based on the `stream_ordering` (newest -> oldest). This is technically important because MSC2716 inserts a bunch of historical messages at the same `depth` so it's best to be prescriptive about which ones we should process first. In reality, I think the code already looped over the historical messages as expected because the database is already in order.
 3. Making the historical state chain and historical event chain float on their own by having no `prev_events` instead of a fake `prev_event` which caused backfill to get clogged with an unresolvable event. Fixes https://github.com/matrix-org/synapse/issues/11091 and https://github.com/matrix-org/synapse/issues/10764
 4. We no longer find connected insertion events by finding a potential `prev_event` connection to the current event we're iterating over. We now solely rely on marker events which when processed, add the insertion event as an extremity and the federating homeserver can ask about it when time calls.
    - Related discussion, https://github.com/matrix-org/synapse/pull/11114#discussion_r741514793


Before | After
--- | ---
![](https://user-images.githubusercontent.com/558581/139218681-b465c862-5c49-4702-a59e-466733b0cf45.png) | ![](https://user-images.githubusercontent.com/558581/146453159-a1609e0a-8324-439d-ae44-e4bce43ac6d1.png)



#### Why aren't we sorting topologically when receiving backfill events?

> The main reason we're going to opt to not sort topologically when receiving backfill events is because it's probably best to do whatever is easiest to make it just work. People will probably have opinions once they look at [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716) which could change whatever implementation anyway.
> 
> As mentioned, ideally we would do this but code necessary to make the fake edges but it gets confusing and gives an impression of “just whyyyy” (feels icky). This problem also dissolves with online topological ordering.
>
> -- https://github.com/matrix-org/synapse/pull/11114#discussion_r741517138

See https://github.com/matrix-org/synapse/pull/11114#discussion_r739610091 for the technical difficulties
2022-02-07 15:54:13 -06:00
Eric Eastwood
84f235aea4
Rename to more clear get_insertion_event_id_by_batch_id (MSC2716) (#11244)
`get_insertion_event_by_batch_id` -> `get_insertion_event_id_by_batch_id`

Split out from https://github.com/matrix-org/synapse/pull/11114
2021-11-08 21:21:10 -06:00
Eric Eastwood
da0040785e
Support sending no state_events_at_start in the MSC2716 /batch_send endpoint (#11188)
As brought up by @tulir, https://matrix.to/#/!SBYNQlpqkwJzFIdzxI:nevarro.space/$Gwnb2ZvXHc3poYXuBhho0cmoYq4KJ11Jh3m5s8kjNOM?via=nevarro.space&via=beeper.com&via=matrix.org

This use case only works if the user is already joined in the current room state
at the given `?prev_event_id`
2021-11-03 03:13:51 -05:00
Patrick Cloke
c01bc5f43d
Add remaining type hints to synapse.events. (#11098) 2021-11-02 09:55:52 -04:00
Eric Eastwood
35d6b914eb
Resolve and share state_groups for all historical events in batch (MSC2716) (#10975)
Resolve and share `state_groups` for all historical events in batch.  This also helps for showing the appropriate avatar/displayname in Element and will work whenever `/messages` has one of the historical messages as the first message in the batch.

This does have the flaw where if you just insert a single historical event somewhere, it probably won't resolve the state correctly from `/messages` or `/context` since it will grab a non historical event above or below with resolved state which never included the historical state back then. For the same reasions, this also does not work in Element between the transition from actual messages to historical messages. In the Gitter case, this isn't really a problem since all of the historical messages are in one big lump at the beginning of the room.

For a future iteration, might be good to look at `/messages` and `/context` to additionally add the `state` for any historical messages in that batch.

---

How are the `state_groups` shared? To illustrate the `state_group` sharing, see this example:


**Before** (new `state_group` for every event 😬, very inefficient):
```
# Tests from https://github.com/matrix-org/complement/pull/206
$ COMPLEMENT_ALWAYS_PRINT_SERVER_LOGS=1 COMPLEMENT_DIR=../complement ./scripts-dev/complement.sh TestBackfillingHistory/parallel/should_resolve_member_state_events_for_historical_events
create_new_client_event m.room.member event=$_JXfwUDIWS6xKGG4SmZXjSFrizhARM7QblhATVWWUcA state_group=None
create_new_client_event org.matrix.msc2716.insertion event=$1ZBfmBKEjg94d-vGYymKrVYeghwBOuGJ3wubU1-I9y0 state_group=9
create_new_client_event org.matrix.msc2716.insertion event=$Mq2JvRetTyclPuozRI682SAjYp3GqRuPc8_cH5-ezPY state_group=10
create_new_client_event m.room.message event=$MfmY4rBQkxrIp8jVwVMTJ4PKnxSigpG9E2cn7S0AtTo state_group=11
create_new_client_event m.room.message event=$uYOv6V8wiF7xHwOMt-60d1AoOIbqLgrDLz6ZIQDdWUI state_group=12
create_new_client_event m.room.message event=$PAbkJRMxb0bX4A6av463faiAhxkE3FEObM1xB4D0UG4 state_group=13
create_new_client_event org.matrix.msc2716.batch event=$Oy_S7AWN7rJQe_MYwGPEy6RtbYklrI-tAhmfiLrCaKI state_group=14
```

**After** (all events in batch sharing `state_group=10`) (the base insertion event has `state_group=8` which matches the `prev_event` we're inserting next to):

```
# Tests from https://github.com/matrix-org/complement/pull/206
$ COMPLEMENT_ALWAYS_PRINT_SERVER_LOGS=1 COMPLEMENT_DIR=../complement ./scripts-dev/complement.sh TestBackfillingHistory/parallel/should_resolve_member_state_events_for_historical_events
create_new_client_event m.room.member event=$PWomJ8PwENYEYuVNoG30gqtybuQQSZ55eldBUSs0i0U state_group=None
create_new_client_event org.matrix.msc2716.insertion event=$e_mCU7Eah9ABF6nQU7lu4E1RxIWccNF05AKaTT5m3lw state_group=9
create_new_client_event org.matrix.msc2716.insertion event=$ui7A3_GdXIcJq0C8GpyrF8X7B3DTjMd_WGCjogax7xU state_group=10
create_new_client_event m.room.message event=$EnTIM5rEGVezQJiYl62uFBl6kJ7B-sMxWqe2D_4FX1I state_group=10
create_new_client_event m.room.message event=$LGx5jGONnBPuNhAuZqHeEoXChd9ryVkuTZatGisOPjk state_group=10
create_new_client_event m.room.message event=$wW0zwoN50lbLu1KoKbybVMxLbKUj7GV_olozIc5i3M0 state_group=10
create_new_client_event org.matrix.msc2716.batch event=$5ZB6dtzqFBCEuMRgpkU201Qhx3WtXZGTz_YgldL6JrQ state_group=10
```
2021-10-13 17:44:00 -05:00
Eric Eastwood
a7d22c36db
Refactor MSC2716 /batch_send endpoint into separate handler functions (#10974) 2021-10-08 18:35:00 -05:00
Eric Eastwood
9fd057b8c5
Ensure (room_id, next_batch_id) is unique to avoid cross-talk/conflicts between batches (MSC2716) (#10877)
Part of [MSC2716](https://github.com/matrix-org/matrix-doc/pull/2716)

Part of https://github.com/matrix-org/synapse/issues/10737
2021-09-28 21:23:16 -05:00
Eric Eastwood
51e2db3598
Rename MSC2716 things from chunk to batch to match /batch_send endpoint (#10838)
See https://github.com/matrix-org/matrix-doc/pull/2716#discussion_r684574497

Dropping support for older MSC2716 room versions so we don't have to worry about
supporting both chunk and batch events.
2021-09-21 15:06:28 -05:00
Eric Eastwood
ee557b5375
Rename /batch_send query parameter from ?prev_event to more obvious usage with ?prev_event_id (MSC2716) (#10839)
As mentioned in https://github.com/matrix-org/matrix-doc/pull/2716#discussion_r705872887
and https://github.com/matrix-org/synapse/issues/10737
2021-09-21 14:10:01 +01:00
Eric Eastwood
145c006ef7
Verify ?chunk_id actually corresponds to an insertion event that exists (MSC2716) (#10776) 2021-09-15 09:34:30 +01:00
Eric Eastwood
1c555527b3
Split out /batch_send meta events to their own fields (MSC2716) (#10777) 2021-09-15 09:30:58 +01:00
Patrick Cloke
d1f1b46c2c
Additional type hints for client REST servlets (part 4) (#10728) 2021-09-01 11:59:32 -04:00
reivilibre
642a42edde
Flatten the synapse.rest.client package (#10600) 2021-08-17 11:57:58 +00:00