diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 8881b009df..919e855f3b 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -38,6 +38,7 @@ from synapse.state import StateResolutionStore
from synapse.storage.background_updates import BackgroundUpdateStore
from synapse.storage.event_federation import EventFederationStore
from synapse.storage.events_worker import EventsWorkerStore
+from synapse.storage.state import StateGroupWorkerStore
from synapse.types import RoomStreamToken, get_domain_from_id
from synapse.util import batch_iter
from synapse.util.async_helpers import ObservableDeferred
@@ -205,7 +206,8 @@ def _retry_on_integrity_error(func):
# inherits from EventFederationStore so that we can call _update_backward_extremities
# and _handle_mult_prev_events (though arguably those could both be moved in here)
-class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore):
+class EventsStore(StateGroupWorkerStore, EventFederationStore, EventsWorkerStore,
+ BackgroundUpdateStore):
EVENT_ORIGIN_SERVER_TS_NAME = "event_origin_server_ts"
EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url"
@@ -2034,55 +2036,37 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
logger.info("[purge] finding redundant state groups")
- # Get all state groups that are only referenced by events that are
- # to be deleted.
- # This works by first getting state groups that we may want to delete,
- # joining against event_to_state_groups to get events that use that
- # state group, then left joining against events_to_purge again. Any
- # state group where the left join produce *no nulls* are referenced
- # only by events that are going to be purged.
+ # Get all state groups that are referenced by events that are to be
+ # deleted. We then go and check if they are referenced by other events
+ # or state groups, and if not we delete them.
txn.execute("""
- SELECT state_group FROM
- (
- SELECT DISTINCT state_group FROM events_to_purge
- INNER JOIN event_to_state_groups USING (event_id)
- ) AS sp
- INNER JOIN event_to_state_groups USING (state_group)
- LEFT JOIN events_to_purge AS ep USING (event_id)
- GROUP BY state_group
- HAVING SUM(CASE WHEN ep.event_id IS NULL THEN 1 ELSE 0 END) = 0
+ SELECT DISTINCT state_group FROM events_to_purge
+ INNER JOIN event_to_state_groups USING (event_id)
""")
- state_rows = txn.fetchall()
- logger.info("[purge] found %i redundant state groups", len(state_rows))
-
- # make a set of the redundant state groups, so that we can look them up
- # efficiently
- state_groups_to_delete = set([sg for sg, in state_rows])
-
- # Now we get all the state groups that rely on these state groups
- logger.info("[purge] finding state groups which depend on redundant"
- " state groups")
- remaining_state_groups = []
- for i in range(0, len(state_rows), 100):
- chunk = [sg for sg, in state_rows[i:i + 100]]
- # look for state groups whose prev_state_group is one we are about
- # to delete
- rows = self._simple_select_many_txn(
- txn,
- table="state_group_edges",
- column="prev_state_group",
- iterable=chunk,
- retcols=["state_group"],
- keyvalues={},
- )
- remaining_state_groups.extend(
- row["state_group"] for row in rows
+ referenced_state_groups = set(sg for sg, in txn)
+ logger.info(
+ "[purge] found %i referenced state groups",
+ len(referenced_state_groups),
+ )
- # exclude state groups we are about to delete: no point in
- # updating them
- if row["state_group"] not in state_groups_to_delete
+ logger.info("[purge] finding state groups that can be deleted")
+
+ state_groups_to_delete, remaining_state_groups = (
+ self._find_unreferenced_groups_during_purge(
+ txn, referenced_state_groups,
)
+ )
+
+ logger.info(
+ "[purge] found %i state groups to delete",
+ len(state_groups_to_delete),
+ )
+
+ logger.info(
+ "[purge] de-delta-ing %i remaining state groups",
+ len(remaining_state_groups),
+ )
# Now we turn the state groups that reference to-be-deleted state
# groups to non delta versions.
@@ -2127,11 +2111,11 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
logger.info("[purge] removing redundant state groups")
txn.executemany(
"DELETE FROM state_groups_state WHERE state_group = ?",
- state_rows
+ ((sg,) for sg in state_groups_to_delete),
)
txn.executemany(
"DELETE FROM state_groups WHERE id = ?",
- state_rows
+ ((sg,) for sg in state_groups_to_delete),
)
logger.info("[purge] removing events from event_to_state_groups")
@@ -2227,6 +2211,85 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
logger.info("[purge] done")
+ def _find_unreferenced_groups_during_purge(self, txn, state_groups):
+ """Used when purging history to figure out which state groups can be
+ deleted and which need to be de-delta'ed (due to one of its prev groups
+ being scheduled for deletion).
+
+ Args:
+ txn
+ state_groups (set[int]): Set of state groups referenced by events
+ that are going to be deleted.
+
+ Returns:
+ tuple[set[int], set[int]]: The set of state groups that can be
+ deleted and the set of state groups that need to be de-delta'ed
+ """
+ # Graph of state group -> previous group
+ graph = {}
+
+ # Set of events that we have found to be referenced by events
+ referenced_groups = set()
+
+ # Set of state groups we've already seen
+ state_groups_seen = set(state_groups)
+
+ # Set of state groups to handle next.
+ next_to_search = set(state_groups)
+ while next_to_search:
+ # We bound size of groups we're looking up at once, to stop the
+ # SQL query getting too big
+ if len(next_to_search) < 100:
+ current_search = next_to_search
+ next_to_search = set()
+ else:
+ current_search = set(itertools.islice(next_to_search, 100))
+ next_to_search -= current_search
+
+ # Check if state groups are referenced
+ sql = """
+ SELECT DISTINCT state_group FROM event_to_state_groups
+ LEFT JOIN events_to_purge AS ep USING (event_id)
+ WHERE state_group IN (%s) AND ep.event_id IS NULL
+ """ % (",".join("?" for _ in current_search),)
+ txn.execute(sql, list(current_search))
+
+ referenced = set(sg for sg, in txn)
+ referenced_groups |= referenced
+
+ # We don't continue iterating up the state group graphs for state
+ # groups that are referenced.
+ current_search -= referenced
+
+ rows = self._simple_select_many_txn(
+ txn,
+ table="state_group_edges",
+ column="prev_state_group",
+ iterable=current_search,
+ keyvalues={},
+ retcols=("prev_state_group", "state_group",),
+ )
+
+ prevs = set(row["state_group"] for row in rows)
+ # We don't bother re-handling groups we've already seen
+ prevs -= state_groups_seen
+ next_to_search |= prevs
+ state_groups_seen |= prevs
+
+ for row in rows:
+ # Note: Each state group can have at most one prev group
+ graph[row["state_group"]] = row["prev_state_group"]
+
+ to_delete = state_groups_seen - referenced_groups
+
+ to_dedelta = set()
+ for sg in referenced_groups:
+ prev_sg = graph.get(sg)
+ if prev_sg and prev_sg in to_delete:
+ to_dedelta.add(sg)
+
+ return to_delete, to_dedelta
+
@defer.inlineCallbacks
def is_event_after(self, event_id1, event_id2):
"""Returns True if event_id1 is after event_id2 in the stream
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index b364719312..bd740e1e45 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
# Remember to update this number every time a change is made to database
# schema files, so the users will be informed on server restarts.
-SCHEMA_VERSION = 51
+SCHEMA_VERSION = 52
dir_path = os.path.abspath(os.path.dirname(__file__))
diff --git a/synapse/storage/schema/delta/52/add_event_to_state_group_index.sql b/synapse/storage/schema/delta/52/add_event_to_state_group_index.sql
new file mode 100644
index 0000000000..91e03d13e1
--- /dev/null
+++ b/synapse/storage/schema/delta/52/add_event_to_state_group_index.sql
@@ -0,0 +1,19 @@
+/* Copyright 2018 New Vector Ltd
+ *
+ * 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.
+ */
+
+-- This is needed to efficiently check for unreferenced state groups during
+-- purge. Added events_to_state_group(state_group) index
+INSERT into background_updates (update_name, progress_json)
+ VALUES ('event_to_state_groups_sg_index', '{}');
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index ef65929bb2..d737bd6778 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -1257,6 +1257,7 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
STATE_GROUP_DEDUPLICATION_UPDATE_NAME = "state_group_state_deduplication"
STATE_GROUP_INDEX_UPDATE_NAME = "state_group_state_type_index"
CURRENT_STATE_INDEX_UPDATE_NAME = "current_state_members_idx"
+ EVENT_STATE_GROUP_INDEX_UPDATE_NAME = "event_to_state_groups_sg_index"
def __init__(self, db_conn, hs):
super(StateStore, self).__init__(db_conn, hs)
@@ -1275,6 +1276,12 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
columns=["state_key"],
where_clause="type='m.room.member'",
)
+ self.register_background_index_update(
+ self.EVENT_STATE_GROUP_INDEX_UPDATE_NAME,
+ index_name="event_to_state_groups_sg_index",
+ table="event_to_state_groups",
+ columns=["state_group"],
+ )
def _store_event_state_mappings_txn(self, txn, events_and_contexts):
state_groups = {}
|
