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![Erik Johnston](/assets/img/avatar_default.png)
This is in preparation for having multiple data stores that offer different functionality, e.g. splitting out state or event storage.
120 lines
4.5 KiB
Python
120 lines
4.5 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2018 Vector Creations Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from synapse.storage._base import SQLBaseStore
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logger = logging.getLogger(__name__)
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class StateDeltasStore(SQLBaseStore):
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def get_current_state_deltas(self, prev_stream_id: int, max_stream_id: int):
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"""Fetch a list of room state changes since the given stream id
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Each entry in the result contains the following fields:
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- stream_id (int)
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- room_id (str)
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- type (str): event type
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- state_key (str):
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- event_id (str|None): new event_id for this state key. None if the
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state has been deleted.
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- prev_event_id (str|None): previous event_id for this state key. None
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if it's new state.
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Args:
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prev_stream_id (int): point to get changes since (exclusive)
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max_stream_id (int): the point that we know has been correctly persisted
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- ie, an upper limit to return changes from.
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Returns:
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Deferred[tuple[int, list[dict]]: A tuple consisting of:
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- the stream id which these results go up to
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- list of current_state_delta_stream rows. If it is empty, we are
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up to date.
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"""
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prev_stream_id = int(prev_stream_id)
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# check we're not going backwards
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assert prev_stream_id <= max_stream_id
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if not self._curr_state_delta_stream_cache.has_any_entity_changed(
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prev_stream_id
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):
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# if the CSDs haven't changed between prev_stream_id and now, we
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# know for certain that they haven't changed between prev_stream_id and
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# max_stream_id.
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return max_stream_id, []
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def get_current_state_deltas_txn(txn):
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# First we calculate the max stream id that will give us less than
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# N results.
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# We arbitarily limit to 100 stream_id entries to ensure we don't
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# select toooo many.
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sql = """
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SELECT stream_id, count(*)
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FROM current_state_delta_stream
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WHERE stream_id > ? AND stream_id <= ?
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GROUP BY stream_id
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ORDER BY stream_id ASC
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LIMIT 100
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"""
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txn.execute(sql, (prev_stream_id, max_stream_id))
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total = 0
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for stream_id, count in txn:
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total += count
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if total > 100:
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# We arbitarily limit to 100 entries to ensure we don't
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# select toooo many.
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logger.debug(
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"Clipping current_state_delta_stream rows to stream_id %i",
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stream_id,
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)
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clipped_stream_id = stream_id
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break
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else:
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# if there's no problem, we may as well go right up to the max_stream_id
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clipped_stream_id = max_stream_id
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# Now actually get the deltas
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sql = """
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SELECT stream_id, room_id, type, state_key, event_id, prev_event_id
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FROM current_state_delta_stream
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WHERE ? < stream_id AND stream_id <= ?
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ORDER BY stream_id ASC
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"""
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txn.execute(sql, (prev_stream_id, clipped_stream_id))
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return clipped_stream_id, self.cursor_to_dict(txn)
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return self.runInteraction(
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"get_current_state_deltas", get_current_state_deltas_txn
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)
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def _get_max_stream_id_in_current_state_deltas_txn(self, txn):
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return self._simple_select_one_onecol_txn(
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txn,
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table="current_state_delta_stream",
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keyvalues={},
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retcol="COALESCE(MAX(stream_id), -1)",
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)
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def get_max_stream_id_in_current_state_deltas(self):
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return self.runInteraction(
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"get_max_stream_id_in_current_state_deltas",
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self._get_max_stream_id_in_current_state_deltas_txn,
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)
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