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Use the chain cover index in get_auth_chain_ids. (#9576)

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This uses a simplified version of get_chain_cover_difference to calculate
auth chain of events.
This commit is contained in:
Patrick Cloke 2021-03-10 09:57:59 -05:00 committed by GitHub
parent 918f6ed827
commit 2a99cc6524
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5 changed files with 226 additions and 11 deletions
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1
changelog.d/9576.misc Normal file
View file

@ -0,0 +1 @@
Improve efficiency of calculating the auth chain in large rooms.

6
synapse/federation/federation_server.py
View file

@ -447,7 +447,7 @@ class FederationServer(FederationBase):
async def _on_state_ids_request_compute(self, room_id, event_id):
state_ids = await self.handler.get_state_ids_for_pdu(room_id, event_id)
auth_chain_ids = await self.store.get_auth_chain_ids(state_ids)
auth_chain_ids = await self.store.get_auth_chain_ids(room_id, state_ids)
return {"pdu_ids": state_ids, "auth_chain_ids": auth_chain_ids}
async def _on_context_state_request_compute(
@ -460,7 +460,9 @@ class FederationServer(FederationBase):
else:
pdus = (await self.state.get_current_state(room_id)).values()
auth_chain = await self.store.get_auth_chain([pdu.event_id for pdu in pdus])
auth_chain = await self.store.get_auth_chain(
room_id, [pdu.event_id for pdu in pdus]
)
return {
"pdus": [pdu.get_pdu_json() for pdu in pdus],

6
synapse/handlers/federation.py
View file

@ -1317,7 +1317,7 @@ class FederationHandler(BaseHandler):
async def on_event_auth(self, event_id: str) -> List[EventBase]:
event = await self.store.get_event(event_id)
auth = await self.store.get_auth_chain(
list(event.auth_event_ids()), include_given=True
event.room_id, list(event.auth_event_ids()), include_given=True
)
return list(auth)
@ -1580,7 +1580,7 @@ class FederationHandler(BaseHandler):
prev_state_ids = await context.get_prev_state_ids()
state_ids = list(prev_state_ids.values())
auth_chain = await self.store.get_auth_chain(state_ids)
auth_chain = await self.store.get_auth_chain(event.room_id, state_ids)
state = await self.store.get_events(list(prev_state_ids.values()))
@ -2219,7 +2219,7 @@ class FederationHandler(BaseHandler):
# Now get the current auth_chain for the event.
local_auth_chain = await self.store.get_auth_chain(
list(event.auth_event_ids()), include_given=True
room_id, list(event.auth_event_ids()), include_given=True
)
# TODO: Check if we would now reject event_id. If so we need to tell

148
synapse/storage/databases/main/event_federation.py
View file

@ -54,11 +54,12 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
) # type: LruCache[str, List[Tuple[str, int]]]
async def get_auth_chain(
self, event_ids: Collection[str], include_given: bool = False
self, room_id: str, event_ids: Collection[str], include_given: bool = False
) -> List[EventBase]:
"""Get auth events for given event_ids. The events *must* be state events.
Args:
room_id: The room the event is in.
event_ids: state events
include_given: include the given events in result
@ -66,24 +67,44 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
list of events
"""
event_ids = await self.get_auth_chain_ids(
event_ids, include_given=include_given
room_id, event_ids, include_given=include_given
)
return await self.get_events_as_list(event_ids)
async def get_auth_chain_ids(
self,
room_id: str,
event_ids: Collection[str],
include_given: bool = False,
) -> List[str]:
"""Get auth events for given event_ids. The events *must* be state events.
Args:
room_id: The room the event is in.
event_ids: state events
include_given: include the given events in result
Returns:
An awaitable which resolve to a list of event_ids
list of event_ids
"""
# Check if we have indexed the room so we can use the chain cover
# algorithm.
room = await self.get_room(room_id)
if room["has_auth_chain_index"]:
try:
return await self.db_pool.runInteraction(
"get_auth_chain_ids_chains",
self._get_auth_chain_ids_using_cover_index_txn,
room_id,
event_ids,
include_given,
)
except _NoChainCoverIndex:
# For whatever reason we don't actually have a chain cover index
# for the events in question, so we fall back to the old method.
pass
return await self.db_pool.runInteraction(
"get_auth_chain_ids",
self._get_auth_chain_ids_txn,
@ -91,9 +112,130 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
include_given,
)
def _get_auth_chain_ids_using_cover_index_txn(
self, txn: Cursor, room_id: str, event_ids: Collection[str], include_given: bool
) -> List[str]:
"""Calculates the auth chain IDs using the chain index."""
# First we look up the chain ID/sequence numbers for the given events.
initial_events = set(event_ids)
# All the events that we've found that are reachable from the events.
seen_events = set() # type: Set[str]
# A map from chain ID to max sequence number of the given events.
event_chains = {} # type: Dict[int, int]
sql = """
SELECT event_id, chain_id, sequence_number
FROM event_auth_chains
WHERE %s
"""
for batch in batch_iter(initial_events, 1000):
clause, args = make_in_list_sql_clause(
txn.database_engine, "event_id", batch
)
txn.execute(sql % (clause,), args)
for event_id, chain_id, sequence_number in txn:
seen_events.add(event_id)
event_chains[chain_id] = max(
sequence_number, event_chains.get(chain_id, 0)
)
# Check that we actually have a chain ID for all the events.
events_missing_chain_info = initial_events.difference(seen_events)
if events_missing_chain_info:
# This can happen due to e.g. downgrade/upgrade of the server. We
# raise an exception and fall back to the previous algorithm.
logger.info(
"Unexpectedly found that events don't have chain IDs in room %s: %s",
room_id,
events_missing_chain_info,
)
raise _NoChainCoverIndex(room_id)
# Now we look up all links for the chains we have, adding chains that
# are reachable from any event.
sql = """
SELECT
origin_chain_id, origin_sequence_number,
target_chain_id, target_sequence_number
FROM event_auth_chain_links
WHERE %s
"""
# A map from chain ID to max sequence number *reachable* from any event ID.
chains = {} # type: Dict[int, int]
# Add all linked chains reachable from initial set of chains.
for batch in batch_iter(event_chains, 1000):
clause, args = make_in_list_sql_clause(
txn.database_engine, "origin_chain_id", batch
)
txn.execute(sql % (clause,), args)
for (
origin_chain_id,
origin_sequence_number,
target_chain_id,
target_sequence_number,
) in txn:
# chains are only reachable if the origin sequence number of
# the link is less than the max sequence number in the
# origin chain.
if origin_sequence_number <= event_chains.get(origin_chain_id, 0):
chains[target_chain_id] = max(
target_sequence_number,
chains.get(target_chain_id, 0),
)
# Add the initial set of chains, excluding the sequence corresponding to
# initial event.
for chain_id, seq_no in event_chains.items():
chains[chain_id] = max(seq_no - 1, chains.get(chain_id, 0))
# Now for each chain we figure out the maximum sequence number reachable
# from *any* event ID. Events with a sequence less than that are in the
# auth chain.
if include_given:
results = initial_events
else:
results = set()
if isinstance(self.database_engine, PostgresEngine):
# We can use `execute_values` to efficiently fetch the gaps when
# using postgres.
sql = """
SELECT event_id
FROM event_auth_chains AS c, (VALUES ?) AS l(chain_id, max_seq)
WHERE
c.chain_id = l.chain_id
AND sequence_number <= max_seq
"""
rows = txn.execute_values(sql, chains.items())
results.update(r for r, in rows)
else:
# For SQLite we just fall back to doing a noddy for loop.
sql = """
SELECT event_id FROM event_auth_chains
WHERE chain_id = ? AND sequence_number <= ?
"""
for chain_id, max_no in chains.items():
txn.execute(sql, (chain_id, max_no))
results.update(r for r, in txn)
return list(results)
def _get_auth_chain_ids_txn(
self, txn: LoggingTransaction, event_ids: Collection[str], include_given: bool
) -> List[str]:
"""Calculates the auth chain IDs.
This is used when we don't have a cover index for the room.
"""
if include_given:
results = set(event_ids)
else:

76
tests/storage/test_event_federation.py
View file

@ -118,8 +118,7 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
r = self.get_success(self.store.get_rooms_with_many_extremities(5, 1, [room1]))
self.assertTrue(r == [room2] or r == [room3])
@parameterized.expand([(True,), (False,)])
def test_auth_difference(self, use_chain_cover_index: bool):
def _setup_auth_chain(self, use_chain_cover_index: bool) -> str:
room_id = "@ROOM:local"
# The silly auth graph we use to test the auth difference algorithm,
@ -165,7 +164,7 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
"j": 1,
}
# Mark the room as not having a cover index
# Mark the room as maybe having a cover index.
def store_room(txn):
self.store.db_pool.simple_insert_txn(
@ -222,6 +221,77 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
)
)
return room_id
@parameterized.expand([(True,), (False,)])
def test_auth_chain_ids(self, use_chain_cover_index: bool):
room_id = self._setup_auth_chain(use_chain_cover_index)
# a and b have the same auth chain.
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["a"]))
self.assertCountEqual(auth_chain_ids, ["e", "f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["b"]))
self.assertCountEqual(auth_chain_ids, ["e", "f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(
self.store.get_auth_chain_ids(room_id, ["a", "b"])
)
self.assertCountEqual(auth_chain_ids, ["e", "f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["c"]))
self.assertCountEqual(auth_chain_ids, ["g", "h", "i", "j", "k"])
# d and e have the same auth chain.
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["d"]))
self.assertCountEqual(auth_chain_ids, ["f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["e"]))
self.assertCountEqual(auth_chain_ids, ["f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["f"]))
self.assertCountEqual(auth_chain_ids, ["g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["g"]))
self.assertCountEqual(auth_chain_ids, ["h", "i", "j", "k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["h"]))
self.assertEqual(auth_chain_ids, ["k"])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["i"]))
self.assertEqual(auth_chain_ids, ["j"])
# j and k have no parents.
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["j"]))
self.assertEqual(auth_chain_ids, [])
auth_chain_ids = self.get_success(self.store.get_auth_chain_ids(room_id, ["k"]))
self.assertEqual(auth_chain_ids, [])
# More complex input sequences.
auth_chain_ids = self.get_success(
self.store.get_auth_chain_ids(room_id, ["b", "c", "d"])
)
self.assertCountEqual(auth_chain_ids, ["e", "f", "g", "h", "i", "j", "k"])
auth_chain_ids = self.get_success(
self.store.get_auth_chain_ids(room_id, ["h", "i"])
)
self.assertCountEqual(auth_chain_ids, ["k", "j"])
# e gets returned even though include_given is false, but it is in the
# auth chain of b.
auth_chain_ids = self.get_success(
self.store.get_auth_chain_ids(room_id, ["b", "e"])
)
self.assertCountEqual(auth_chain_ids, ["e", "f", "g", "h", "i", "j", "k"])
# Test include_given.
auth_chain_ids = self.get_success(
self.store.get_auth_chain_ids(room_id, ["i"], include_given=True)
)
self.assertCountEqual(auth_chain_ids, ["i", "j"])
@parameterized.expand([(True,), (False,)])
def test_auth_difference(self, use_chain_cover_index: bool):
room_id = self._setup_auth_chain(use_chain_cover_index)
# Now actually test that various combinations give the right result:
difference = self.get_success(