diff --git a/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres b/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres new file mode 100644 index 0000000000..bdbbab5738 --- /dev/null +++ b/synapse/storage/databases/main/schema/delta/58/19instance_map.sql.postgres @@ -0,0 +1,25 @@ +/* Copyright 2020 The Matrix.org Foundation C.I.C + * + * 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. + */ + + +-- A unique and immutable mapping between instance name and an integer ID. This +-- let's us refer to instances via a small ID in e.g. stream tokens, without +-- having to encode the full name. +CREATE TABLE instance_map ( + instance_id SERIAL PRIMARY KEY, + instance_name TEXT NOT NULL +); + +CREATE UNIQUE INDEX instance_map_idx ON instance_map(instance_name); diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py index 37249f1e3f..e6449d68b8 100644 --- a/synapse/storage/databases/main/stream.py +++ b/synapse/storage/databases/main/stream.py @@ -54,6 +54,7 @@ from synapse.storage.database import ( from synapse.storage.databases.main.events_worker import EventsWorkerStore from synapse.storage.engines import BaseDatabaseEngine, PostgresEngine from synapse.types import Collection, PersistedEventPosition, RoomStreamToken +from synapse.util.caches.descriptors import cached from synapse.util.caches.stream_change_cache import StreamChangeCache if TYPE_CHECKING: @@ -1095,6 +1096,58 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore, metaclass=abc.ABCMeta): return (events, token) + @cached() + async def get_id_for_instance(self, instance_name: str) -> int: + """Get a unique, immutable ID that corresponds to the instance. + """ + + def _get_id_for_instance_txn(txn): + instance_id = self.db_pool.simple_select_one_onecol_txn( + txn, + table="instance_map", + keyvalues={"instance_name": instance_name}, + retcol="instance_id", + allow_none=True, + ) + if instance_id is not None: + return instance_id + + # If we don't have an entry upsert one. + # + # We could do this before the first check, and rely on the cache for + # efficiency, but each UPSERT causes the next ID to increment which + # can quickly bloat the size of the generated IDs for new instances. + self.db_pool.simple_upsert_txn( + txn, + table="instance_map", + keyvalues={"instance_name": instance_name}, + values={}, + ) + + return self.db_pool.simple_select_one_onecol_txn( + txn, + table="instance_map", + keyvalues={"instance_name": instance_name}, + retcol="instance_id", + ) + + return await self.db_pool.runInteraction( + "get_id_for_instance", _get_id_for_instance_txn + ) + + @cached() + async def get_name_from_instance_id(self, instance_id: int) -> str: + """Get the instance name from an ID previously returned by + `get_id_for_instance`. + """ + + return await self.db_pool.simple_select_one_onecol( + table="instance_map", + keyvalues={"instance_id": instance_id}, + retcol="instance_name", + desc="get_name_from_instance_id", + ) + class StreamStore(StreamWorkerStore): def get_room_max_stream_ordering(self) -> int: