From 8f35f8148e1a7ce3ac249e2d2052854409f2c0d6 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Mon, 23 Oct 2023 16:57:30 +0100 Subject: [PATCH] Fix bug where a new writer advances their token too quickly (#16473) * Fix bug where a new writer advances their token too quickly When starting a new writer (for e.g. persisting events), the `MultiWriterIdGenerator` doesn't have a minimum token for it as there are no rows matching that new writer in the DB. This results in the the first stream ID it acquired being announced as persisted *before* it actually finishes persisting, if another writer gets and persists a subsequent stream ID. This is due to the logic of setting the minimum persisted position to the minimum known position of across all writers, and the new writer starts off not being considered. * Fix sending out POSITIONs when our token advances without update Broke in #14820 * For replication HTTP requests, only wait for minimal position --- changelog.d/16473.bugfix | 1 + .../synapse_architecture/streams.md | 13 +- synapse/replication/http/_base.py | 2 +- synapse/replication/tcp/streams/_base.py | 129 +++++++++++------ synapse/replication/tcp/streams/events.py | 8 +- synapse/replication/tcp/streams/federation.py | 15 +- .../replication/tcp/streams/partial_state.py | 10 +- synapse/storage/util/id_generators.py | 68 ++++++++- tests/storage/test_id_generators.py | 136 ++++++++++++++++-- 9 files changed, 305 insertions(+), 77 deletions(-) create mode 100644 changelog.d/16473.bugfix diff --git a/changelog.d/16473.bugfix b/changelog.d/16473.bugfix new file mode 100644 index 000000000000..4f4a0380cd77 --- /dev/null +++ b/changelog.d/16473.bugfix @@ -0,0 +1 @@ +Fix a long-standing, exceedingly rare edge case where the first event persisted by a new event persister worker might not be sent down `/sync`. diff --git a/docs/development/synapse_architecture/streams.md b/docs/development/synapse_architecture/streams.md index bee0b8a8c0a2..67d92acfa1fc 100644 --- a/docs/development/synapse_architecture/streams.md +++ b/docs/development/synapse_architecture/streams.md @@ -51,17 +51,24 @@ will be inserted with that ID. For any given stream reader (including writers themselves), we may define a per-writer current stream ID: -> The current stream ID _for a writer W_ is the largest stream ID such that +> A current stream ID _for a writer W_ is the largest stream ID such that > all transactions added by W with equal or smaller ID have completed. Similarly, there is a "linear" notion of current stream ID: -> The "linear" current stream ID is the largest stream ID such that +> A "linear" current stream ID is the largest stream ID such that > all facts (added by any writer) with equal or smaller ID have completed. Because different stream readers A and B learn about new facts at different times, A and B may disagree about current stream IDs. Put differently: we should think of stream readers as being independent of each other, proceeding through a stream of facts at different rates. +The above definition does not give a unique current stream ID, in fact there can +be a range of current stream IDs. Synapse uses both the minimum and maximum IDs +for different purposes. Most often the maximum is used, as its generally +beneficial for workers to advance their IDs as soon as possible. However, the +minimum is used in situations where e.g. another worker is going to wait until +the stream advances past a position. + **NB.** For both senses of "current", that if a writer opens a transaction that never completes, the current stream ID will never advance beyond that writer's last written stream ID. For single-writer streams, the per-writer current ID and the linear current ID are the same. @@ -114,7 +121,7 @@ Writers need to track: - track their current position (i.e. its own per-writer stream ID). - their facts currently awaiting completion. -At startup, +At startup, - the current position of that writer can be found by querying the database (which suggests that facts need to be written to the database atomically, in a transaction); and - there are no facts awaiting completion. diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py index 63cf24a14d94..7476839db584 100644 --- a/synapse/replication/http/_base.py +++ b/synapse/replication/http/_base.py @@ -238,7 +238,7 @@ async def send_request( data[_STREAM_POSITION_KEY] = { "streams": { - stream.NAME: stream.current_token(local_instance_name) + stream.NAME: stream.minimal_local_current_token() for stream in streams }, "instance_name": local_instance_name, diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py index c6088a0f99f8..5c4d228f3d7c 100644 --- a/synapse/replication/tcp/streams/_base.py +++ b/synapse/replication/tcp/streams/_base.py @@ -33,6 +33,7 @@ if TYPE_CHECKING: from synapse.server import HomeServer + from synapse.storage.util.id_generators import AbstractStreamIdGenerator logger = logging.getLogger(__name__) @@ -107,22 +108,10 @@ def parse_row(cls, row: StreamRow) -> Any: def __init__( self, local_instance_name: str, - current_token_function: Callable[[str], Token], update_function: UpdateFunction, ): """Instantiate a Stream - `current_token_function` and `update_function` are callbacks which - should be implemented by subclasses. - - `current_token_function` takes an instance name, which is a writer to - the stream, and returns the position in the stream of the writer (as - viewed from the current process). On the writer process this is where - the writer has successfully written up to, whereas on other processes - this is the position which we have received updates up to over - replication. (Note that most streams have a single writer and so their - implementations ignore the instance name passed in). - `update_function` is called to get updates for this stream between a pair of stream tokens. See the `UpdateFunction` type definition for more info. @@ -133,12 +122,28 @@ def __init__( update_function: callback go get stream updates, as above """ self.local_instance_name = local_instance_name - self.current_token = current_token_function self.update_function = update_function # The token from which we last asked for updates self.last_token = self.current_token(self.local_instance_name) + def current_token(self, instance_name: str) -> Token: + """This takes an instance name, which is a writer to + the stream, and returns the position in the stream of the writer (as + viewed from the current process). + """ + # We can't make this an abstract class as it makes mypy unhappy. + raise NotImplementedError() + + def minimal_local_current_token(self) -> Token: + """Tries to return a minimal current token for the local instance, + i.e. for writers this would be the last successful write. + + If local instance is not a writer (or has written yet) then falls back + to returning the normal "current token". + """ + raise NotImplementedError() + def discard_updates_and_advance(self) -> None: """Called when the stream should advance but the updates would be discarded, e.g. when there are no currently connected workers. @@ -190,6 +195,25 @@ async def get_updates_since( return updates, upto_token, limited +class _StreamFromIdGen(Stream): + """Helper class for simple streams that use a stream ID generator""" + + def __init__( + self, + local_instance_name: str, + update_function: UpdateFunction, + stream_id_gen: "AbstractStreamIdGenerator", + ): + self._stream_id_gen = stream_id_gen + super().__init__(local_instance_name, update_function) + + def current_token(self, instance_name: str) -> Token: + return self._stream_id_gen.get_current_token_for_writer(instance_name) + + def minimal_local_current_token(self) -> Token: + return self._stream_id_gen.get_minimal_local_current_token() + + def current_token_without_instance( current_token: Callable[[], int] ) -> Callable[[str], int]: @@ -242,17 +266,21 @@ def __init__(self, hs: "HomeServer"): self.store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - self._current_token, self.store.get_all_new_backfill_event_rows, ) - def _current_token(self, instance_name: str) -> int: + def current_token(self, instance_name: str) -> Token: # The backfill stream over replication operates on *positive* numbers, # which means we need to negate it. return -self.store._backfill_id_gen.get_current_token_for_writer(instance_name) + def minimal_local_current_token(self) -> Token: + # The backfill stream over replication operates on *positive* numbers, + # which means we need to negate it. + return -self.store._backfill_id_gen.get_minimal_local_current_token() -class PresenceStream(Stream): + +class PresenceStream(_StreamFromIdGen): @attr.s(slots=True, frozen=True, auto_attribs=True) class PresenceStreamRow: user_id: str @@ -283,9 +311,7 @@ def __init__(self, hs: "HomeServer"): update_function = make_http_update_function(hs, self.NAME) super().__init__( - hs.get_instance_name(), - current_token_without_instance(store.get_current_presence_token), - update_function, + hs.get_instance_name(), update_function, store._presence_id_gen ) @@ -305,13 +331,18 @@ class PresenceFederationStreamRow: ROW_TYPE = PresenceFederationStreamRow def __init__(self, hs: "HomeServer"): - federation_queue = hs.get_presence_handler().get_federation_queue() + self._federation_queue = hs.get_presence_handler().get_federation_queue() super().__init__( hs.get_instance_name(), - federation_queue.get_current_token, - federation_queue.get_replication_rows, + self._federation_queue.get_replication_rows, ) + def current_token(self, instance_name: str) -> Token: + return self._federation_queue.get_current_token(instance_name) + + def minimal_local_current_token(self) -> Token: + return self._federation_queue.get_current_token(self.local_instance_name) + class TypingStream(Stream): @attr.s(slots=True, frozen=True, auto_attribs=True) @@ -341,20 +372,25 @@ def __init__(self, hs: "HomeServer"): update_function: Callable[ [str, int, int, int], Awaitable[Tuple[List[Tuple[int, Any]], int, bool]] ] = typing_writer_handler.get_all_typing_updates - current_token_function = typing_writer_handler.get_current_token + self.current_token_function = typing_writer_handler.get_current_token else: # Query the typing writer process update_function = make_http_update_function(hs, self.NAME) - current_token_function = hs.get_typing_handler().get_current_token + self.current_token_function = hs.get_typing_handler().get_current_token super().__init__( hs.get_instance_name(), - current_token_without_instance(current_token_function), update_function, ) + def current_token(self, instance_name: str) -> Token: + return self.current_token_function() + + def minimal_local_current_token(self) -> Token: + return self.current_token_function() -class ReceiptsStream(Stream): + +class ReceiptsStream(_StreamFromIdGen): @attr.s(slots=True, frozen=True, auto_attribs=True) class ReceiptsStreamRow: room_id: str @@ -371,12 +407,12 @@ def __init__(self, hs: "HomeServer"): store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - current_token_without_instance(store.get_max_receipt_stream_id), store.get_all_updated_receipts, + store._receipts_id_gen, ) -class PushRulesStream(Stream): +class PushRulesStream(_StreamFromIdGen): """A user has changed their push rules""" @attr.s(slots=True, frozen=True, auto_attribs=True) @@ -387,20 +423,16 @@ class PushRulesStreamRow: ROW_TYPE = PushRulesStreamRow def __init__(self, hs: "HomeServer"): - self.store = hs.get_datastores().main + store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - self._current_token, - self.store.get_all_push_rule_updates, + store.get_all_push_rule_updates, + store._push_rules_stream_id_gen, ) - def _current_token(self, instance_name: str) -> int: - push_rules_token = self.store.get_max_push_rules_stream_id() - return push_rules_token - -class PushersStream(Stream): +class PushersStream(_StreamFromIdGen): """A user has added/changed/removed a pusher""" @attr.s(slots=True, frozen=True, auto_attribs=True) @@ -418,8 +450,8 @@ def __init__(self, hs: "HomeServer"): super().__init__( hs.get_instance_name(), - current_token_without_instance(store.get_pushers_stream_token), store.get_all_updated_pushers_rows, + store._pushers_id_gen, ) @@ -447,15 +479,20 @@ class CachesStreamRow: ROW_TYPE = CachesStreamRow def __init__(self, hs: "HomeServer"): - store = hs.get_datastores().main + self.store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - store.get_cache_stream_token_for_writer, - store.get_all_updated_caches, + self.store.get_all_updated_caches, ) + def current_token(self, instance_name: str) -> Token: + return self.store.get_cache_stream_token_for_writer(instance_name) + + def minimal_local_current_token(self) -> Token: + return self.current_token(self.local_instance_name) + -class DeviceListsStream(Stream): +class DeviceListsStream(_StreamFromIdGen): """Either a user has updated their devices or a remote server needs to be told about a device update. """ @@ -473,8 +510,8 @@ def __init__(self, hs: "HomeServer"): self.store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - current_token_without_instance(self.store.get_device_stream_token), self._update_function, + self.store._device_list_id_gen, ) async def _update_function( @@ -525,7 +562,7 @@ async def _update_function( return updates, upper_limit_token, devices_limited or signatures_limited -class ToDeviceStream(Stream): +class ToDeviceStream(_StreamFromIdGen): """New to_device messages for a client""" @attr.s(slots=True, frozen=True, auto_attribs=True) @@ -539,12 +576,12 @@ def __init__(self, hs: "HomeServer"): store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - current_token_without_instance(store.get_to_device_stream_token), store.get_all_new_device_messages, + store._device_inbox_id_gen, ) -class AccountDataStream(Stream): +class AccountDataStream(_StreamFromIdGen): """Global or per room account data was changed""" @attr.s(slots=True, frozen=True, auto_attribs=True) @@ -560,8 +597,8 @@ def __init__(self, hs: "HomeServer"): self.store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - current_token_without_instance(self.store.get_max_account_data_stream_id), self._update_function, + self.store._account_data_id_gen, ) async def _update_function( diff --git a/synapse/replication/tcp/streams/events.py b/synapse/replication/tcp/streams/events.py index da6d948e1ba3..38823113d818 100644 --- a/synapse/replication/tcp/streams/events.py +++ b/synapse/replication/tcp/streams/events.py @@ -19,10 +19,10 @@ import attr from synapse.replication.tcp.streams._base import ( - Stream, StreamRow, StreamUpdateResult, Token, + _StreamFromIdGen, ) if TYPE_CHECKING: @@ -139,7 +139,7 @@ class EventsStreamAllStateRow(BaseEventsStreamRow): TypeToRow = {Row.TypeId: Row for Row in _EventRows} -class EventsStream(Stream): +class EventsStream(_StreamFromIdGen): """We received a new event, or an event went from being an outlier to not""" NAME = "events" @@ -147,9 +147,7 @@ class EventsStream(Stream): def __init__(self, hs: "HomeServer"): self._store = hs.get_datastores().main super().__init__( - hs.get_instance_name(), - self._store._stream_id_gen.get_current_token_for_writer, - self._update_function, + hs.get_instance_name(), self._update_function, self._store._stream_id_gen ) async def _update_function( diff --git a/synapse/replication/tcp/streams/federation.py b/synapse/replication/tcp/streams/federation.py index 4046bdec6931..7f5af5852c1c 100644 --- a/synapse/replication/tcp/streams/federation.py +++ b/synapse/replication/tcp/streams/federation.py @@ -18,6 +18,7 @@ from synapse.replication.tcp.streams._base import ( Stream, + Token, current_token_without_instance, make_http_update_function, ) @@ -47,7 +48,7 @@ def __init__(self, hs: "HomeServer"): # will be a real FederationSender, which has stubs for current_token and # get_replication_rows.) federation_sender = hs.get_federation_sender() - current_token = current_token_without_instance( + self.current_token_func = current_token_without_instance( federation_sender.get_current_token ) update_function: Callable[ @@ -57,15 +58,21 @@ def __init__(self, hs: "HomeServer"): elif hs.should_send_federation(): # federation sender: Query master process update_function = make_http_update_function(hs, self.NAME) - current_token = self._stub_current_token + self.current_token_func = self._stub_current_token else: # other worker: stub out the update function (we're not interested in # any updates so when we get a POSITION we do nothing) update_function = self._stub_update_function - current_token = self._stub_current_token + self.current_token_func = self._stub_current_token - super().__init__(hs.get_instance_name(), current_token, update_function) + super().__init__(hs.get_instance_name(), update_function) + + def current_token(self, instance_name: str) -> Token: + return self.current_token_func(instance_name) + + def minimal_local_current_token(self) -> Token: + return self.current_token(self.local_instance_name) @staticmethod def _stub_current_token(instance_name: str) -> int: diff --git a/synapse/replication/tcp/streams/partial_state.py b/synapse/replication/tcp/streams/partial_state.py index a8ce5ffd7289..ad181d7e9331 100644 --- a/synapse/replication/tcp/streams/partial_state.py +++ b/synapse/replication/tcp/streams/partial_state.py @@ -15,7 +15,7 @@ import attr -from synapse.replication.tcp.streams import Stream +from synapse.replication.tcp.streams._base import _StreamFromIdGen if TYPE_CHECKING: from synapse.server import HomeServer @@ -27,7 +27,7 @@ class UnPartialStatedRoomStreamRow: room_id: str -class UnPartialStatedRoomStream(Stream): +class UnPartialStatedRoomStream(_StreamFromIdGen): """ Stream to notify about rooms becoming un-partial-stated; that is, when the background sync finishes such that we now have full state for @@ -41,8 +41,8 @@ def __init__(self, hs: "HomeServer"): store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - store.get_un_partial_stated_rooms_token, store.get_un_partial_stated_rooms_from_stream, + store._un_partial_stated_rooms_stream_id_gen, ) @@ -56,7 +56,7 @@ class UnPartialStatedEventStreamRow: rejection_status_changed: bool -class UnPartialStatedEventStream(Stream): +class UnPartialStatedEventStream(_StreamFromIdGen): """ Stream to notify about events becoming un-partial-stated. """ @@ -68,6 +68,6 @@ def __init__(self, hs: "HomeServer"): store = hs.get_datastores().main super().__init__( hs.get_instance_name(), - store.get_un_partial_stated_events_token, store.get_un_partial_stated_events_from_stream, + store._un_partial_stated_events_stream_id_gen, ) diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py index d2c874b9a8d7..9c3eafb562a5 100644 --- a/synapse/storage/util/id_generators.py +++ b/synapse/storage/util/id_generators.py @@ -133,6 +133,15 @@ def get_current_token_for_writer(self, instance_name: str) -> int: """ raise NotImplementedError() + @abc.abstractmethod + def get_minimal_local_current_token(self) -> int: + """Tries to return a minimal current token for the local instance, + i.e. for writers this would be the last successful write. + + If local instance is not a writer (or has written yet) then falls back + to returning the normal "current token". + """ + @abc.abstractmethod def get_next(self) -> AsyncContextManager[int]: """ @@ -312,6 +321,9 @@ def get_current_token(self) -> int: def get_current_token_for_writer(self, instance_name: str) -> int: return self.get_current_token() + def get_minimal_local_current_token(self) -> int: + return self.get_current_token() + class MultiWriterIdGenerator(AbstractStreamIdGenerator): """Generates and tracks stream IDs for a stream with multiple writers. @@ -408,6 +420,11 @@ def __init__( # The maximum stream ID that we have seen been allocated across any writer. self._max_seen_allocated_stream_id = 1 + # The maximum position of the local instance. This can be higher than + # the corresponding position in `current_positions` table when there are + # no active writes in progress. + self._max_position_of_local_instance = self._max_seen_allocated_stream_id + self._sequence_gen = PostgresSequenceGenerator(sequence_name) # We check that the table and sequence haven't diverged. @@ -427,6 +444,16 @@ def __init__( self._current_positions.values(), default=1 ) + # For the case where `stream_positions` is not up to date, + # `_persisted_upto_position` may be higher. + self._max_seen_allocated_stream_id = max( + self._max_seen_allocated_stream_id, self._persisted_upto_position + ) + + # Bump our local maximum position now that we've loaded things from the + # DB. + self._max_position_of_local_instance = self._max_seen_allocated_stream_id + if not writers: # If there have been no explicit writers given then any instance can # write to the stream. In which case, let's pre-seed our own @@ -545,6 +572,14 @@ def sort_by_stream_id_key_func(row: Tuple[str, int]) -> int: if instance == self._instance_name: self._current_positions[instance] = stream_id + if self._writers: + # If we have explicit writers then make sure that each instance has + # a position. + for writer in self._writers: + self._current_positions.setdefault( + writer, self._persisted_upto_position + ) + cur.close() def _load_next_id_txn(self, txn: Cursor) -> int: @@ -688,6 +723,9 @@ def _mark_id_as_finished(self, next_id: int) -> None: if new_cur: curr = self._current_positions.get(self._instance_name, 0) self._current_positions[self._instance_name] = max(curr, new_cur) + self._max_position_of_local_instance = max( + curr, new_cur, self._max_position_of_local_instance + ) self._add_persisted_position(next_id) @@ -702,10 +740,26 @@ def get_current_token_for_writer(self, instance_name: str) -> int: # persisted up to position. This stops Synapse from doing a full table # scan when a new writer announces itself over replication. with self._lock: - return self._return_factor * self._current_positions.get( + if self._instance_name == instance_name: + return self._return_factor * self._max_position_of_local_instance + + pos = self._current_positions.get( instance_name, self._persisted_upto_position ) + # We want to return the maximum "current token" that we can for a + # writer, this helps ensure that streams progress as fast as + # possible. + pos = max(pos, self._persisted_upto_position) + + return self._return_factor * pos + + def get_minimal_local_current_token(self) -> int: + with self._lock: + return self._return_factor * self._current_positions.get( + self._instance_name, self._persisted_upto_position + ) + def get_positions(self) -> Dict[str, int]: """Get a copy of the current positon map. @@ -774,6 +828,18 @@ def _add_persisted_position(self, new_id: int) -> None: self._persisted_upto_position = max(min_curr, self._persisted_upto_position) + # Advance our local max position. + self._max_position_of_local_instance = max( + self._max_position_of_local_instance, self._persisted_upto_position + ) + + if not self._unfinished_ids and not self._in_flight_fetches: + # If we don't have anything in flight, it's safe to advance to the + # max seen stream ID. + self._max_position_of_local_instance = max( + self._max_seen_allocated_stream_id, self._max_position_of_local_instance + ) + # We now iterate through the seen positions, discarding those that are # less than the current min positions, and incrementing the min position # if its exactly one greater. diff --git a/tests/storage/test_id_generators.py b/tests/storage/test_id_generators.py index 9174fb096470..fd53b0644c12 100644 --- a/tests/storage/test_id_generators.py +++ b/tests/storage/test_id_generators.py @@ -259,8 +259,9 @@ def test_empty(self) -> None: id_gen = self._create_id_generator() - # The table is empty so we expect an empty map for positions - self.assertEqual(id_gen.get_positions(), {}) + # The table is empty so we expect the map for positions to have a dummy + # minimum value. + self.assertEqual(id_gen.get_positions(), {"master": 1}) def test_single_instance(self) -> None: """Test that reads and writes from a single process are handled @@ -349,15 +350,12 @@ def test_multi_instance(self) -> None: first_id_gen = self._create_id_generator("first", writers=["first", "second"]) second_id_gen = self._create_id_generator("second", writers=["first", "second"]) - # The first ID gen will notice that it can advance its token to 7 as it - # has no in progress writes... self.assertEqual(first_id_gen.get_positions(), {"first": 3, "second": 7}) - self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 3) + self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 7) self.assertEqual(first_id_gen.get_current_token_for_writer("second"), 7) - # ... but the second ID gen doesn't know that. self.assertEqual(second_id_gen.get_positions(), {"first": 3, "second": 7}) - self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 3) + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 7) self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7) # Try allocating a new ID gen and check that we only see position @@ -398,6 +396,56 @@ async def _get_next_async2() -> None: second_id_gen.advance("first", 8) self.assertEqual(second_id_gen.get_positions(), {"first": 8, "second": 9}) + def test_multi_instance_empty_row(self) -> None: + """Test that reads and writes from multiple processes are handled + correctly, when one of the writers starts without any rows. + """ + # Insert some rows for two out of three of the ID gens. + self._insert_rows("first", 3) + self._insert_rows("second", 4) + + first_id_gen = self._create_id_generator( + "first", writers=["first", "second", "third"] + ) + second_id_gen = self._create_id_generator( + "second", writers=["first", "second", "third"] + ) + third_id_gen = self._create_id_generator( + "third", writers=["first", "second", "third"] + ) + + self.assertEqual( + first_id_gen.get_positions(), {"first": 3, "second": 7, "third": 7} + ) + self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 7) + self.assertEqual(first_id_gen.get_current_token_for_writer("second"), 7) + self.assertEqual(first_id_gen.get_current_token_for_writer("third"), 7) + + self.assertEqual( + second_id_gen.get_positions(), {"first": 3, "second": 7, "third": 7} + ) + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 7) + self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7) + self.assertEqual(second_id_gen.get_current_token_for_writer("third"), 7) + + # Try allocating a new ID gen and check that we only see position + # advanced after we leave the context manager. + + async def _get_next_async() -> None: + async with third_id_gen.get_next() as stream_id: + self.assertEqual(stream_id, 8) + + self.assertEqual( + third_id_gen.get_positions(), {"first": 3, "second": 7, "third": 7} + ) + self.assertEqual(third_id_gen.get_persisted_upto_position(), 7) + + self.get_success(_get_next_async()) + + self.assertEqual( + third_id_gen.get_positions(), {"first": 3, "second": 7, "third": 8} + ) + def test_get_next_txn(self) -> None: """Test that the `get_next_txn` function works correctly.""" @@ -600,6 +648,70 @@ def _insert(txn: Cursor) -> None: with self.assertRaises(IncorrectDatabaseSetup): self._create_id_generator("first") + def test_minimal_local_token(self) -> None: + self._insert_rows("first", 3) + self._insert_rows("second", 4) + + first_id_gen = self._create_id_generator("first", writers=["first", "second"]) + second_id_gen = self._create_id_generator("second", writers=["first", "second"]) + + self.assertEqual(first_id_gen.get_positions(), {"first": 3, "second": 7}) + self.assertEqual(first_id_gen.get_minimal_local_current_token(), 3) + + self.assertEqual(second_id_gen.get_positions(), {"first": 3, "second": 7}) + self.assertEqual(second_id_gen.get_minimal_local_current_token(), 7) + + def test_current_token_gap(self) -> None: + """Test that getting the current token for a writer returns the maximal + token when there are no writes. + """ + self._insert_rows("first", 3) + self._insert_rows("second", 4) + + first_id_gen = self._create_id_generator( + "first", writers=["first", "second", "third"] + ) + second_id_gen = self._create_id_generator( + "second", writers=["first", "second", "third"] + ) + + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 7) + self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7) + self.assertEqual(second_id_gen.get_current_token(), 7) + + # Check that the first ID gen advancing causes the second ID gen to + # advance (as the second ID gen has nothing in flight). + + async def _get_next_async() -> None: + async with first_id_gen.get_next_mult(2): + pass + + self.get_success(_get_next_async()) + second_id_gen.advance("first", 9) + + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 9) + self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 9) + self.assertEqual(second_id_gen.get_current_token(), 7) + + # Check that the first ID gen advancing doesn't advance the second ID + # gen when the second ID gen has stuff in flight. + self.get_success(_get_next_async()) + + ctxmgr = second_id_gen.get_next() + self.get_success(ctxmgr.__aenter__()) + + second_id_gen.advance("first", 11) + + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 11) + self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 9) + self.assertEqual(second_id_gen.get_current_token(), 7) + + self.get_success(ctxmgr.__aexit__(None, None, None)) + + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 11) + self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 12) + self.assertEqual(second_id_gen.get_current_token(), 7) + class BackwardsMultiWriterIdGeneratorTestCase(HomeserverTestCase): """Tests MultiWriterIdGenerator that produce *negative* stream IDs.""" @@ -712,8 +824,8 @@ async def _get_next_async() -> None: self.get_success(_get_next_async()) - self.assertEqual(id_gen_1.get_positions(), {"first": -1}) - self.assertEqual(id_gen_2.get_positions(), {"first": -1}) + self.assertEqual(id_gen_1.get_positions(), {"first": -1, "second": -1}) + self.assertEqual(id_gen_2.get_positions(), {"first": -1, "second": -1}) self.assertEqual(id_gen_1.get_persisted_upto_position(), -1) self.assertEqual(id_gen_2.get_persisted_upto_position(), -1) @@ -822,11 +934,11 @@ def test_load_existing_stream(self) -> None: second_id_gen = self._create_id_generator("second", writers=["first", "second"]) self.assertEqual(first_id_gen.get_positions(), {"first": 3, "second": 6}) - self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 3) - self.assertEqual(first_id_gen.get_current_token_for_writer("second"), 6) + self.assertEqual(first_id_gen.get_current_token_for_writer("first"), 7) + self.assertEqual(first_id_gen.get_current_token_for_writer("second"), 7) self.assertEqual(first_id_gen.get_persisted_upto_position(), 7) self.assertEqual(second_id_gen.get_positions(), {"first": 3, "second": 7}) - self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 3) + self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 7) self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7) self.assertEqual(second_id_gen.get_persisted_upto_position(), 7)