MatrixSynapse/synapse/storage/state_deltas.py

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# -*- coding: utf-8 -*-
# Copyright 2018 Vector Creations 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.
import logging
from synapse.storage._base import SQLBaseStore
logger = logging.getLogger(__name__)
class StateDeltasStore(SQLBaseStore):
def get_current_state_deltas(self, prev_stream_id):
"""Fetch a list of room state changes since the given stream id
Each entry in the result contains the following fields:
- stream_id (int)
- room_id (str)
- type (str): event type
- state_key (str):
- event_id (str|None): new event_id for this state key. None if the
state has been deleted.
- prev_event_id (str|None): previous event_id for this state key. None
if it's new state.
Args:
prev_stream_id (int): point to get changes since (exclusive)
Returns:
Deferred[list[dict]]: results
"""
prev_stream_id = int(prev_stream_id)
if not self._curr_state_delta_stream_cache.has_any_entity_changed(
prev_stream_id
):
return []
def get_current_state_deltas_txn(txn):
# First we calculate the max stream id that will give us less than
# N results.
# We arbitarily limit to 100 stream_id entries to ensure we don't
# select toooo many.
sql = """
SELECT stream_id, count(*)
FROM current_state_delta_stream
WHERE stream_id > ?
GROUP BY stream_id
ORDER BY stream_id ASC
LIMIT 100
"""
txn.execute(sql, (prev_stream_id,))
total = 0
max_stream_id = prev_stream_id
for max_stream_id, count in txn:
total += count
if total > 100:
# We arbitarily limit to 100 entries to ensure we don't
# select toooo many.
break
# Now actually get the deltas
sql = """
SELECT stream_id, room_id, type, state_key, event_id, prev_event_id
FROM current_state_delta_stream
WHERE ? < stream_id AND stream_id <= ?
ORDER BY stream_id ASC
"""
txn.execute(sql, (prev_stream_id, max_stream_id))
return self.cursor_to_dict(txn)
return self.runInteraction(
"get_current_state_deltas", get_current_state_deltas_txn
)
def get_max_stream_id_in_current_state_deltas(self):
return self._simple_select_one_onecol(
table="current_state_delta_stream",
keyvalues={},
retcol="COALESCE(MAX(stream_id), -1)",
desc="get_max_stream_id_in_current_state_deltas",
)