Back out in-flight state caching changes. (#12126)

1 files changed, 0 insertions, 454 deletions

diff --git a/tests/storage/databases/test_state_store.py b/tests/storage/databases/test_state_store.py
deleted file mode 100644
index 2b484c95a9..0000000000
--- a/tests/storage/databases/test_state_store.py
+++ /dev/null
@@ -1,454 +0,0 @@
-# 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 parameterized import parameterized
-
-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,
-    state_filter_rough_priority_comparator,
-)
-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)
-
-    @parameterized.expand([(False,), (True,)])
-    def test_ordering_of_request_reuse(self, reverse: bool) -> None:
-        """
-        Tests that 'larger' in-flight requests are ordered first.
-
-        This is mostly a design decision in order to prevent a request from
-        hanging on to multiple queries when it would have been sufficient to
-        hang on to only one bigger query.
-
-        The 'size' of a state filter is a rough heuristic.
-
-        - requests two pieces of state, one 'larger' than the other, but each
-          spawning a query
-        - requests a third piece of state
-        - completes the larger of the first two queries
-        - checks that the third request gets completed (and doesn't needlessly
-          wait for the other query)
-
-        Parameters:
-            reverse: whether to reverse the order of the initial requests, to ensure
-                     that the effect doesn't depend on the order of request submission.
-        """
-
-        # We add in an extra state type to make sure that both requests spawn
-        # queries which are not optimised out.
-        state_filters = [
-            StateFilter.freeze(
-                {"state.type": {"A"}, "other.state.type": {"a"}}, include_others=False
-            ),
-            StateFilter.freeze(
-                {
-                    "state.type": None,
-                    "other.state.type": {"b"},
-                    # The current rough size comparator uses the number of state types
-                    # as an indicator of size.
-                    # To influence it to make this state filter bigger than the previous one,
-                    # we add another dummy state type.
-                    "extra.state.type": {"c"},
-                },
-                include_others=False,
-            ),
-        ]
-
-        if reverse:
-            # For fairness, we perform one test run with the list reversed.
-            state_filters.reverse()
-            smallest_state_filter_idx = 1
-            biggest_state_filter_idx = 0
-        else:
-            smallest_state_filter_idx = 0
-            biggest_state_filter_idx = 1
-
-        # This assertion is for our own sanity more than anything else.
-        self.assertLess(
-            state_filter_rough_priority_comparator(
-                state_filters[biggest_state_filter_idx]
-            ),
-            state_filter_rough_priority_comparator(
-                state_filters[smallest_state_filter_idx]
-            ),
-            "Test invalid: bigger state filter is not actually bigger.",
-        )
-
-        # Spawn the initial two requests
-        for state_filter in state_filters:
-            ensureDeferred(
-                self.state_datastore._get_state_for_group_using_inflight_cache(
-                    42,
-                    state_filter,
-                )
-            )
-
-        # Spawn a third request
-        req = ensureDeferred(
-            self.state_datastore._get_state_for_group_using_inflight_cache(
-                42,
-                StateFilter.freeze(
-                    {
-                        "state.type": {"A"},
-                    },
-                    include_others=False,
-                ),
-            )
-        )
-        self.pump(by=0.1)
-
-        self.assertFalse(req.called)
-
-        # Complete the largest request's query to make sure that the final request
-        # only waits for that one (and doesn't needlessly wait for both queries)
-        self._complete_request_fake(
-            *self.get_state_group_calls[biggest_state_filter_idx]
-        )
-
-        # That should have been sufficient to complete the third request
-        self.assertTrue(req.called)