diff --git a/changelog.d/10870.misc b/changelog.d/10870.misc
deleted file mode 100644
index 3af049b969..0000000000
--- a/changelog.d/10870.misc
+++ /dev/null
@@ -1 +0,0 @@
-Deduplicate in-flight requests in `_get_state_for_groups`.
diff --git a/changelog.d/11608.misc b/changelog.d/11608.misc
deleted file mode 100644
index 3af049b969..0000000000
--- a/changelog.d/11608.misc
+++ /dev/null
@@ -1 +0,0 @@
-Deduplicate in-flight requests in `_get_state_for_groups`.
diff --git a/changelog.d/11610.misc b/changelog.d/11610.misc
deleted file mode 100644
index 3af049b969..0000000000
--- a/changelog.d/11610.misc
+++ /dev/null
@@ -1 +0,0 @@
-Deduplicate in-flight requests in `_get_state_for_groups`.
diff --git a/changelog.d/12033.misc b/changelog.d/12033.misc
deleted file mode 100644
index 3af049b969..0000000000
--- a/changelog.d/12033.misc
+++ /dev/null
@@ -1 +0,0 @@
-Deduplicate in-flight requests in `_get_state_for_groups`.
diff --git a/changelog.d/12126.removal b/changelog.d/12126.removal
new file mode 100644
index 0000000000..8c8bf6ee7e
--- /dev/null
+++ b/changelog.d/12126.removal
@@ -0,0 +1 @@
+Back out in-flight state caching changes.
\ No newline at end of file
diff --git a/synapse/storage/databases/state/store.py b/synapse/storage/databases/state/store.py
index dadf3d1e3a..7614d76ac6 100644
--- a/synapse/storage/databases/state/store.py
+++ b/synapse/storage/databases/state/store.py
@@ -13,24 +13,11 @@
# limitations under the License.
import logging
-from typing import (
- TYPE_CHECKING,
- Collection,
- Dict,
- Iterable,
- Optional,
- Sequence,
- Set,
- Tuple,
-)
+from typing import TYPE_CHECKING, Collection, Dict, Iterable, List, Optional, Set, Tuple
import attr
-from sortedcontainers import SortedDict
-
-from twisted.internet import defer
from synapse.api.constants import EventTypes
-from synapse.logging.context import make_deferred_yieldable, run_in_background
from synapse.storage._base import SQLBaseStore
from synapse.storage.database import (
DatabasePool,
@@ -42,12 +29,6 @@ from synapse.storage.state import StateFilter
from synapse.storage.types import Cursor
from synapse.storage.util.sequence import build_sequence_generator
from synapse.types import MutableStateMap, StateKey, StateMap
-from synapse.util import unwrapFirstError
-from synapse.util.async_helpers import (
- AbstractObservableDeferred,
- ObservableDeferred,
- yieldable_gather_results,
-)
from synapse.util.caches.descriptors import cached
from synapse.util.caches.dictionary_cache import DictionaryCache
@@ -56,8 +37,8 @@ if TYPE_CHECKING:
logger = logging.getLogger(__name__)
+
MAX_STATE_DELTA_HOPS = 100
-MAX_INFLIGHT_REQUESTS_PER_GROUP = 5
@attr.s(slots=True, frozen=True, auto_attribs=True)
@@ -73,24 +54,6 @@ class _GetStateGroupDelta:
return len(self.delta_ids) if self.delta_ids else 0
-def state_filter_rough_priority_comparator(
- state_filter: StateFilter,
-) -> Tuple[int, int]:
- """
- Returns a comparable value that roughly indicates the relative size of this
- state filter compared to others.
- 'Larger' state filters should sort first when using ascending order, so
- this is essentially the opposite of 'size'.
- It should be treated as a rough guide only and should not be interpreted to
- have any particular meaning. The representation may also change
-
- The current implementation returns a tuple of the form:
- * -1 for include_others, 0 otherwise
- * -(number of entries in state_filter.types)
- """
- return -int(state_filter.include_others), -len(state_filter.types)
-
-
class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
"""A data store for fetching/storing state groups."""
@@ -143,12 +106,6 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
500000,
)
- # Current ongoing get_state_for_groups in-flight requests
- # {group ID -> {StateFilter -> ObservableDeferred}}
- self._state_group_inflight_requests: Dict[
- int, SortedDict[StateFilter, AbstractObservableDeferred[StateMap[str]]]
- ] = {}
-
def get_max_state_group_txn(txn: Cursor) -> int:
txn.execute("SELECT COALESCE(max(id), 0) FROM state_groups")
return txn.fetchone()[0] # type: ignore
@@ -200,7 +157,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
)
async def _get_state_groups_from_groups(
- self, groups: Sequence[int], state_filter: StateFilter
+ self, groups: List[int], state_filter: StateFilter
) -> Dict[int, StateMap[str]]:
"""Returns the state groups for a given set of groups from the
database, filtering on types of state events.
@@ -271,170 +228,6 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
return state_filter.filter_state(state_dict_ids), not missing_types
- def _get_state_for_group_gather_inflight_requests(
- self, group: int, state_filter_left_over: StateFilter
- ) -> Tuple[Sequence[AbstractObservableDeferred[StateMap[str]]], StateFilter]:
- """
- Attempts to gather in-flight requests and re-use them to retrieve state
- for the given state group, filtered with the given state filter.
-
- If there are more than MAX_INFLIGHT_REQUESTS_PER_GROUP in-flight requests,
- and there *still* isn't enough information to complete the request by solely
- reusing others, a full state filter will be requested to ensure that subsequent
- requests can reuse this request.
-
- Used as part of _get_state_for_group_using_inflight_cache.
-
- Returns:
- Tuple of two values:
- A sequence of ObservableDeferreds to observe
- A StateFilter representing what else needs to be requested to fulfill the request
- """
-
- inflight_requests = self._state_group_inflight_requests.get(group)
- if inflight_requests is None:
- # no requests for this group, need to retrieve it all ourselves
- return (), state_filter_left_over
-
- # The list of ongoing requests which will help narrow the current request.
- reusable_requests = []
-
- # Iterate over existing requests in roughly biggest-first order.
- for request_state_filter in inflight_requests:
- request_deferred = inflight_requests[request_state_filter]
- new_state_filter_left_over = state_filter_left_over.approx_difference(
- request_state_filter
- )
- if new_state_filter_left_over == state_filter_left_over:
- # Reusing this request would not gain us anything, so don't bother.
- continue
-
- reusable_requests.append(request_deferred)
- state_filter_left_over = new_state_filter_left_over
- if state_filter_left_over == StateFilter.none():
- # we have managed to collect enough of the in-flight requests
- # to cover our StateFilter and give us the state we need.
- break
-
- if (
- state_filter_left_over != StateFilter.none()
- and len(inflight_requests) >= MAX_INFLIGHT_REQUESTS_PER_GROUP
- ):
- # There are too many requests for this group.
- # To prevent even more from building up, we request the whole
- # state filter to guarantee that we can be reused by any subsequent
- # requests for this state group.
- return (), StateFilter.all()
-
- return reusable_requests, state_filter_left_over
-
- async def _get_state_for_group_fire_request(
- self, group: int, state_filter: StateFilter
- ) -> StateMap[str]:
- """
- Fires off a request to get the state at a state group,
- potentially filtering by type and/or state key.
-
- This request will be tracked in the in-flight request cache and automatically
- removed when it is finished.
-
- Used as part of _get_state_for_group_using_inflight_cache.
-
- Args:
- group: ID of the state group for which we want to get state
- state_filter: the state filter used to fetch state from the database
- """
- cache_sequence_nm = self._state_group_cache.sequence
- cache_sequence_m = self._state_group_members_cache.sequence
-
- # Help the cache hit ratio by expanding the filter a bit
- db_state_filter = state_filter.return_expanded()
-
- async def _the_request() -> StateMap[str]:
- group_to_state_dict = await self._get_state_groups_from_groups(
- (group,), state_filter=db_state_filter
- )
-
- # Now let's update the caches
- self._insert_into_cache(
- group_to_state_dict,
- db_state_filter,
- cache_seq_num_members=cache_sequence_m,
- cache_seq_num_non_members=cache_sequence_nm,
- )
-
- # Remove ourselves from the in-flight cache
- group_request_dict = self._state_group_inflight_requests[group]
- del group_request_dict[db_state_filter]
- if not group_request_dict:
- # If there are no more requests in-flight for this group,
- # clean up the cache by removing the empty dictionary
- del self._state_group_inflight_requests[group]
-
- return group_to_state_dict[group]
-
- # We don't immediately await the result, so must use run_in_background
- # But we DO await the result before the current log context (request)
- # finishes, so don't need to run it as a background process.
- request_deferred = run_in_background(_the_request)
- observable_deferred = ObservableDeferred(request_deferred, consumeErrors=True)
-
- # Insert the ObservableDeferred into the cache
- group_request_dict = self._state_group_inflight_requests.setdefault(
- group, SortedDict(state_filter_rough_priority_comparator)
- )
- group_request_dict[db_state_filter] = observable_deferred
-
- return await make_deferred_yieldable(observable_deferred.observe())
-
- async def _get_state_for_group_using_inflight_cache(
- self, group: int, state_filter: StateFilter
- ) -> MutableStateMap[str]:
- """
- Gets the state at a state group, potentially filtering by type and/or
- state key.
-
- 1. Calls _get_state_for_group_gather_inflight_requests to gather any
- ongoing requests which might overlap with the current request.
- 2. Fires a new request, using _get_state_for_group_fire_request,
- for any state which cannot be gathered from ongoing requests.
-
- Args:
- group: ID of the state group for which we want to get state
- state_filter: the state filter used to fetch state from the database
- Returns:
- state map
- """
-
- # first, figure out whether we can re-use any in-flight requests
- # (and if so, what would be left over)
- (
- reusable_requests,
- state_filter_left_over,
- ) = self._get_state_for_group_gather_inflight_requests(group, state_filter)
-
- if state_filter_left_over != StateFilter.none():
- # Fetch remaining state
- remaining = await self._get_state_for_group_fire_request(
- group, state_filter_left_over
- )
- assembled_state: MutableStateMap[str] = dict(remaining)
- else:
- assembled_state = {}
-
- gathered = await make_deferred_yieldable(
- defer.gatherResults(
- (r.observe() for r in reusable_requests), consumeErrors=True
- )
- ).addErrback(unwrapFirstError)
-
- # assemble our result.
- for result_piece in gathered:
- assembled_state.update(result_piece)
-
- # Filter out any state that may be more than what we asked for.
- return state_filter.filter_state(assembled_state)
-
async def _get_state_for_groups(
self, groups: Iterable[int], state_filter: Optional[StateFilter] = None
) -> Dict[int, MutableStateMap[str]]:
@@ -476,17 +269,31 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
if not incomplete_groups:
return state
- async def get_from_cache(group: int, state_filter: StateFilter) -> None:
- state[group] = await self._get_state_for_group_using_inflight_cache(
- group, state_filter
- )
+ cache_sequence_nm = self._state_group_cache.sequence
+ cache_sequence_m = self._state_group_members_cache.sequence
- await yieldable_gather_results(
- get_from_cache,
- incomplete_groups,
- state_filter,
+ # Help the cache hit ratio by expanding the filter a bit
+ db_state_filter = state_filter.return_expanded()
+
+ group_to_state_dict = await self._get_state_groups_from_groups(
+ list(incomplete_groups), state_filter=db_state_filter
)
+ # Now lets update the caches
+ self._insert_into_cache(
+ group_to_state_dict,
+ db_state_filter,
+ cache_seq_num_members=cache_sequence_m,
+ cache_seq_num_non_members=cache_sequence_nm,
+ )
+
+ # And finally update the result dict, by filtering out any extra
+ # stuff we pulled out of the database.
+ for group, group_state_dict in group_to_state_dict.items():
+ # We just replace any existing entries, as we will have loaded
+ # everything we need from the database anyway.
+ state[group] = state_filter.filter_state(group_state_dict)
+
return state
def _get_state_for_groups_using_cache(
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)
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