MatrixSynapse/tests/storage/databases/test_state_store.py

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# Copyright 2022 The Matrix.org Foundation C.I.C.
#
# 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.
import typing
from typing import Dict, List, Sequence, Tuple
from unittest.mock import patch
from twisted.internet.defer import Deferred, ensureDeferred
from twisted.test.proto_helpers import MemoryReactor
from synapse.api.constants import EventTypes
from synapse.storage.databases.state.store import MAX_INFLIGHT_REQUESTS_PER_GROUP
from synapse.storage.state import StateFilter
from synapse.types import StateMap
from synapse.util import Clock
from tests.unittest import HomeserverTestCase
if typing.TYPE_CHECKING:
from synapse.server import HomeServer
# StateFilter for ALL non-m.room.member state events
ALL_NON_MEMBERS_STATE_FILTER = StateFilter.freeze(
types={EventTypes.Member: set()},
include_others=True,
)
FAKE_STATE = {
(EventTypes.Member, "@alice:test"): "join",
(EventTypes.Member, "@bob:test"): "leave",
(EventTypes.Member, "@charlie:test"): "invite",
("test.type", "a"): "AAA",
("test.type", "b"): "BBB",
("other.event.type", "state.key"): "123",
}
class StateGroupInflightCachingTestCase(HomeserverTestCase):
def prepare(
self, reactor: MemoryReactor, clock: Clock, homeserver: "HomeServer"
) -> None:
self.state_storage = homeserver.get_storage().state
self.state_datastore = homeserver.get_datastores().state
# Patch out the `_get_state_groups_from_groups`.
# This is useful because it lets us pretend we have a slow database.
get_state_groups_patch = patch.object(
self.state_datastore,
"_get_state_groups_from_groups",
self._fake_get_state_groups_from_groups,
)
get_state_groups_patch.start()
self.addCleanup(get_state_groups_patch.stop)
self.get_state_group_calls: List[
Tuple[Tuple[int, ...], StateFilter, Deferred[Dict[int, StateMap[str]]]]
] = []
def _fake_get_state_groups_from_groups(
self, groups: Sequence[int], state_filter: StateFilter
) -> "Deferred[Dict[int, StateMap[str]]]":
d: Deferred[Dict[int, StateMap[str]]] = Deferred()
self.get_state_group_calls.append((tuple(groups), state_filter, d))
return d
def _complete_request_fake(
self,
groups: Tuple[int, ...],
state_filter: StateFilter,
d: "Deferred[Dict[int, StateMap[str]]]",
) -> None:
"""
Assemble a fake database response and complete the database request.
"""
# Return a filtered copy of the fake state
d.callback({group: state_filter.filter_state(FAKE_STATE) for group in groups})
def test_duplicate_requests_deduplicated(self) -> None:
"""
Tests that duplicate requests for state are deduplicated.
This test:
- requests some state (state group 42, 'all' state filter)
- requests it again, before the first request finishes
- checks to see that only one database query was made
- completes the database query
- checks that both requests see the same retrieved state
"""
req1 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.all()
)
)
self.pump(by=0.1)
# This should have gone to the database
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
req2 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.all()
)
)
self.pump(by=0.1)
# No more calls should have gone to the database
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
self.assertFalse(req2.called)
groups, sf, d = self.get_state_group_calls[0]
self.assertEqual(groups, (42,))
self.assertEqual(sf, StateFilter.all())
# Now we can complete the request
self._complete_request_fake(groups, sf, d)
self.assertEqual(self.get_success(req1), FAKE_STATE)
self.assertEqual(self.get_success(req2), FAKE_STATE)
def test_smaller_request_deduplicated(self) -> None:
"""
Tests that duplicate requests for state are deduplicated.
This test:
- requests some state (state group 42, 'all' state filter)
- requests a subset of that state, before the first request finishes
- checks to see that only one database query was made
- completes the database query
- checks that both requests see the correct retrieved state
"""
req1 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.from_types((("test.type", None),))
)
)
self.pump(by=0.1)
# This should have gone to the database
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
req2 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.from_types((("test.type", "b"),))
)
)
self.pump(by=0.1)
# No more calls should have gone to the database, because the second
# request was already in the in-flight cache!
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
self.assertFalse(req2.called)
groups, sf, d = self.get_state_group_calls[0]
self.assertEqual(groups, (42,))
# The state filter is expanded internally for increased cache hit rate,
# so we the database sees a wider state filter than requested.
self.assertEqual(sf, ALL_NON_MEMBERS_STATE_FILTER)
# Now we can complete the request
self._complete_request_fake(groups, sf, d)
self.assertEqual(
self.get_success(req1),
{("test.type", "a"): "AAA", ("test.type", "b"): "BBB"},
)
self.assertEqual(self.get_success(req2), {("test.type", "b"): "BBB"})
def test_partially_overlapping_request_deduplicated(self) -> None:
"""
Tests that partially-overlapping requests are partially deduplicated.
This test:
- requests a single type of wildcard state
(This is internally expanded to be all non-member state)
- requests the entire state in parallel
- checks to see that two database queries were made, but that the second
one is only for member state.
- completes the database queries
- checks that both requests have the correct result.
"""
req1 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.from_types((("test.type", None),))
)
)
self.pump(by=0.1)
# This should have gone to the database
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
req2 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.all()
)
)
self.pump(by=0.1)
# Because it only partially overlaps, this also went to the database
self.assertEqual(len(self.get_state_group_calls), 2)
self.assertFalse(req1.called)
self.assertFalse(req2.called)
# First request:
groups, sf, d = self.get_state_group_calls[0]
self.assertEqual(groups, (42,))
# The state filter is expanded internally for increased cache hit rate,
# so we the database sees a wider state filter than requested.
self.assertEqual(sf, ALL_NON_MEMBERS_STATE_FILTER)
self._complete_request_fake(groups, sf, d)
# Second request:
groups, sf, d = self.get_state_group_calls[1]
self.assertEqual(groups, (42,))
# The state filter is narrowed to only request membership state, because
# the remainder of the state is already being queried in the first request!
self.assertEqual(
sf, StateFilter.freeze({EventTypes.Member: None}, include_others=False)
)
self._complete_request_fake(groups, sf, d)
# Check the results are correct
self.assertEqual(
self.get_success(req1),
{("test.type", "a"): "AAA", ("test.type", "b"): "BBB"},
)
self.assertEqual(self.get_success(req2), FAKE_STATE)
def test_in_flight_requests_stop_being_in_flight(self) -> None:
"""
Tests that in-flight request deduplication doesn't somehow 'hold on'
to completed requests: once they're done, they're taken out of the
in-flight cache.
"""
req1 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.all()
)
)
self.pump(by=0.1)
# This should have gone to the database
self.assertEqual(len(self.get_state_group_calls), 1)
self.assertFalse(req1.called)
# Complete the request right away.
self._complete_request_fake(*self.get_state_group_calls[0])
self.assertTrue(req1.called)
# Send off another request
req2 = ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42, StateFilter.all()
)
)
self.pump(by=0.1)
# It should have gone to the database again, because the previous request
# isn't in-flight and therefore isn't available for deduplication.
self.assertEqual(len(self.get_state_group_calls), 2)
self.assertFalse(req2.called)
# Complete the request right away.
self._complete_request_fake(*self.get_state_group_calls[1])
self.assertTrue(req2.called)
groups, sf, d = self.get_state_group_calls[0]
self.assertEqual(self.get_success(req1), FAKE_STATE)
self.assertEqual(self.get_success(req2), FAKE_STATE)
def test_inflight_requests_capped(self) -> None:
"""
Tests that the number of in-flight requests is capped to 5.
- requests several pieces of state separately
(5 to hit the limit, 1 to 'shunt out', another that comes after the
group has been 'shunted out')
- checks to see that the torrent of requests is shunted out by
rewriting one of the filters as the 'all' state filter
- requests after that one do not cause any additional queries
"""
# 5 at the time of writing.
CAP_COUNT = MAX_INFLIGHT_REQUESTS_PER_GROUP
reqs = []
# Request 7 different keys (1 to 7) of the `some.state` type.
for req_id in range(CAP_COUNT + 2):
reqs.append(
ensureDeferred(
self.state_datastore._get_state_for_group_using_inflight_cache(
42,
StateFilter.freeze(
{"some.state": {str(req_id + 1)}}, include_others=False
),
)
)
)
self.pump(by=0.1)
# There should only be 6 calls to the database, not 7.
self.assertEqual(len(self.get_state_group_calls), CAP_COUNT + 1)
# Assert that the first 5 are exact requests for the individual pieces
# wanted
for req_id in range(CAP_COUNT):
groups, sf, d = self.get_state_group_calls[req_id]
self.assertEqual(
sf,
StateFilter.freeze(
{"some.state": {str(req_id + 1)}}, include_others=False
),
)
# The 6th request should be the 'all' state filter
groups, sf, d = self.get_state_group_calls[CAP_COUNT]
self.assertEqual(sf, StateFilter.all())
# Complete the queries and check which requests complete as a result
for req_id in range(CAP_COUNT):
# This request should not have been completed yet
self.assertFalse(reqs[req_id].called)
groups, sf, d = self.get_state_group_calls[req_id]
self._complete_request_fake(groups, sf, d)
# This should have only completed this one request
self.assertTrue(reqs[req_id].called)
# Now complete the final query; the last 2 requests should complete
# as a result
self.assertFalse(reqs[CAP_COUNT].called)
self.assertFalse(reqs[CAP_COUNT + 1].called)
groups, sf, d = self.get_state_group_calls[CAP_COUNT]
self._complete_request_fake(groups, sf, d)
self.assertTrue(reqs[CAP_COUNT].called)
self.assertTrue(reqs[CAP_COUNT + 1].called)