diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index b99cf2d8cd..31082bb16a 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -13,42 +13,46 @@
# 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 heapq
import logging
-from collections import namedtuple
+from collections import defaultdict, namedtuple
from typing import (
+ Any,
Awaitable,
+ Callable,
+ DefaultDict,
Dict,
Iterable,
List,
Optional,
Sequence,
Set,
+ Tuple,
Union,
overload,
)
import attr
from frozendict import frozendict
-from prometheus_client import Histogram
+from prometheus_client import Counter, Histogram
from typing_extensions import Literal
from synapse.api.constants import EventTypes
from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, StateResolutionVersions
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
+from synapse.logging.context import ContextResourceUsage
from synapse.logging.utils import log_function
from synapse.state import v1, v2
from synapse.storage.databases.main.events_worker import EventRedactBehaviour
from synapse.storage.roommember import ProfileInfo
from synapse.types import Collection, StateMap
-from synapse.util import Clock
from synapse.util.async_helpers import Linearizer
from synapse.util.caches.expiringcache import ExpiringCache
from synapse.util.metrics import Measure, measure_func
logger = logging.getLogger(__name__)
-
+metrics_logger = logging.getLogger("synapse.state.metrics")
# Metrics for number of state groups involved in a resolution.
state_groups_histogram = Histogram(
@@ -459,6 +463,33 @@ class StateHandler:
return {key: state_map[ev_id] for key, ev_id in new_state.items()}
+@attr.s(slots=True)
+class _StateResMetrics:
+ """Keeps track of some usage metrics about state res."""
+
+ # System and User CPU time, in seconds
+ cpu_time = attr.ib(type=float, default=0.0)
+
+ # time spent on database transactions (excluding scheduling time). This roughly
+ # corresponds to the amount of work done on the db server, excluding event fetches.
+ db_time = attr.ib(type=float, default=0.0)
+
+ # number of events fetched from the db.
+ db_events = attr.ib(type=int, default=0)
+
+
+_biggest_room_by_cpu_counter = Counter(
+ "synapse_state_res_cpu_for_biggest_room_seconds",
+ "CPU time spent performing state resolution for the single most expensive "
+ "room for state resolution",
+)
+_biggest_room_by_db_counter = Counter(
+ "synapse_state_res_db_for_biggest_room_seconds",
+ "Database time spent performing state resolution for the single most "
+ "expensive room for state resolution",
+)
+
+
class StateResolutionHandler:
"""Responsible for doing state conflict resolution.
@@ -481,6 +512,17 @@ class StateResolutionHandler:
reset_expiry_on_get=True,
)
+ #
+ # stuff for tracking time spent on state-res by room
+ #
+
+ # tracks the amount of work done on state res per room
+ self._state_res_metrics = defaultdict(
+ _StateResMetrics
+ ) # type: DefaultDict[str, _StateResMetrics]
+
+ self.clock.looping_call(self._report_metrics, 120 * 1000)
+
@log_function
async def resolve_state_groups(
self,
@@ -578,21 +620,83 @@ class StateResolutionHandler:
Returns:
a map from (type, state_key) to event_id.
"""
- with Measure(self.clock, "state._resolve_events"):
- v = KNOWN_ROOM_VERSIONS[room_version]
- if v.state_res == StateResolutionVersions.V1:
- return await v1.resolve_events_with_store(
- room_id, state_sets, event_map, state_res_store.get_events
- )
- else:
- return await v2.resolve_events_with_store(
- self.clock,
- room_id,
- room_version,
- state_sets,
- event_map,
- state_res_store,
- )
+ try:
+ with Measure(self.clock, "state._resolve_events") as m:
+ v = KNOWN_ROOM_VERSIONS[room_version]
+ if v.state_res == StateResolutionVersions.V1:
+ return await v1.resolve_events_with_store(
+ room_id, state_sets, event_map, state_res_store.get_events
+ )
+ else:
+ return await v2.resolve_events_with_store(
+ self.clock,
+ room_id,
+ room_version,
+ state_sets,
+ event_map,
+ state_res_store,
+ )
+ finally:
+ self._record_state_res_metrics(room_id, m.get_resource_usage())
+
+ def _record_state_res_metrics(self, room_id: str, rusage: ContextResourceUsage):
+ room_metrics = self._state_res_metrics[room_id]
+ room_metrics.cpu_time += rusage.ru_utime + rusage.ru_stime
+ room_metrics.db_time += rusage.db_txn_duration_sec
+ room_metrics.db_events += rusage.evt_db_fetch_count
+
+ def _report_metrics(self):
+ if not self._state_res_metrics:
+ # no state res has happened since the last iteration: don't bother logging.
+ return
+
+ self._report_biggest(
+ lambda i: i.cpu_time, "CPU time", _biggest_room_by_cpu_counter,
+ )
+
+ self._report_biggest(
+ lambda i: i.db_time, "DB time", _biggest_room_by_db_counter,
+ )
+
+ self._state_res_metrics.clear()
+
+ def _report_biggest(
+ self,
+ extract_key: Callable[[_StateResMetrics], Any],
+ metric_name: str,
+ prometheus_counter_metric: Counter,
+ ) -> None:
+ """Report metrics on the biggest rooms for state res
+
+ Args:
+ extract_key: a callable which, given a _StateResMetrics, extracts a single
+ metric to sort by.
+ metric_name: the name of the metric we have extracted, for the log line
+ prometheus_counter_metric: a prometheus metric recording the sum of the
+ the extracted metric
+ """
+ n_to_log = 10
+ if not metrics_logger.isEnabledFor(logging.DEBUG):
+ # only need the most expensive if we don't have debug logging, which
+ # allows nlargest() to degrade to max()
+ n_to_log = 1
+
+ items = self._state_res_metrics.items()
+
+ # log the N biggest rooms
+ biggest = heapq.nlargest(
+ n_to_log, items, key=lambda i: extract_key(i[1])
+ ) # type: List[Tuple[str, _StateResMetrics]]
+ metrics_logger.debug(
+ "%i biggest rooms for state-res by %s: %s",
+ len(biggest),
+ metric_name,
+ ["%s (%gs)" % (r, extract_key(m)) for (r, m) in biggest],
+ )
+
+ # report info on the single biggest to prometheus
+ _, biggest_metrics = biggest[0]
+ prometheus_counter_metric.inc(extract_key(biggest_metrics))
def _make_state_cache_entry(
|
