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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: int, max_stream_id: int):
- """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)
- max_stream_id (int): the point that we know has been correctly persisted
- - ie, an upper limit to return changes from.
- Returns:
- Deferred[tuple[int, list[dict]]: A tuple consisting of:
- - the stream id which these results go up to
- - list of current_state_delta_stream rows. If it is empty, we are
- up to date.
- """
- prev_stream_id = int(prev_stream_id)
- # check we're not going backwards
- assert prev_stream_id <= max_stream_id
- if not self._curr_state_delta_stream_cache.has_any_entity_changed(
- prev_stream_id
- ):
- # if the CSDs haven't changed between prev_stream_id and now, we
- # know for certain that they haven't changed between prev_stream_id and
- # max_stream_id.
- return max_stream_id, []
- 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 > ? AND stream_id <= ?
- GROUP BY stream_id
- ORDER BY stream_id ASC
- LIMIT 100
- """
- txn.execute(sql, (prev_stream_id, max_stream_id))
- total = 0
- for stream_id, count in txn:
- total += count
- if total > 100:
- # We arbitarily limit to 100 entries to ensure we don't
- # select toooo many.
- logger.debug(
- "Clipping current_state_delta_stream rows to stream_id %i",
- stream_id,
- )
- clipped_stream_id = stream_id
- break
- else:
- # if there's no problem, we may as well go right up to the max_stream_id
- clipped_stream_id = max_stream_id
- # 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, clipped_stream_id))
- return clipped_stream_id, self.db.cursor_to_dict(txn)
- return self.db.runInteraction(
- "get_current_state_deltas", get_current_state_deltas_txn
- )
- def _get_max_stream_id_in_current_state_deltas_txn(self, txn):
- return self.db.simple_select_one_onecol_txn(
- txn,
- table="current_state_delta_stream",
- keyvalues={},
- retcol="COALESCE(MAX(stream_id), -1)",
- )
- def get_max_stream_id_in_current_state_deltas(self):
- return self.db.runInteraction(
- "get_max_stream_id_in_current_state_deltas",
- self._get_max_stream_id_in_current_state_deltas_txn,
- )
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