anonymousland-synapse/synapse/storage/engines/_base.py
Erik Johnston ae5b2a72c0
Reduce serialization errors in MultiWriterIdGen (#8456)
We call `_update_stream_positions_table_txn` a lot, which is an UPSERT
that can conflict in `REPEATABLE READ` isolation level. Instead of doing
a transaction consisting of a single query we may as well run it outside
of a transaction.
2020-10-07 15:15:57 +01:00

117 lines
3.1 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2015, 2016 OpenMarket 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 abc
from typing import Generic, TypeVar
from synapse.storage.types import Connection
class IncorrectDatabaseSetup(RuntimeError):
pass
ConnectionType = TypeVar("ConnectionType", bound=Connection)
class BaseDatabaseEngine(Generic[ConnectionType], metaclass=abc.ABCMeta):
def __init__(self, module, database_config: dict):
self.module = module
@property
@abc.abstractmethod
def single_threaded(self) -> bool:
...
@property
@abc.abstractmethod
def can_native_upsert(self) -> bool:
"""
Do we support native UPSERTs?
"""
...
@property
@abc.abstractmethod
def supports_tuple_comparison(self) -> bool:
"""
Do we support comparing tuples, i.e. `(a, b) > (c, d)`?
"""
...
@property
@abc.abstractmethod
def supports_using_any_list(self) -> bool:
"""
Do we support using `a = ANY(?)` and passing a list
"""
...
@abc.abstractmethod
def check_database(
self, db_conn: ConnectionType, allow_outdated_version: bool = False
) -> None:
...
@abc.abstractmethod
def check_new_database(self, txn) -> None:
"""Gets called when setting up a brand new database. This allows us to
apply stricter checks on new databases versus existing database.
"""
...
@abc.abstractmethod
def convert_param_style(self, sql: str) -> str:
...
@abc.abstractmethod
def on_new_connection(self, db_conn: ConnectionType) -> None:
...
@abc.abstractmethod
def is_deadlock(self, error: Exception) -> bool:
...
@abc.abstractmethod
def is_connection_closed(self, conn: ConnectionType) -> bool:
...
@abc.abstractmethod
def lock_table(self, txn, table: str) -> None:
...
@property
@abc.abstractmethod
def server_version(self) -> str:
"""Gets a string giving the server version. For example: '3.22.0'
"""
...
@abc.abstractmethod
def in_transaction(self, conn: Connection) -> bool:
"""Whether the connection is currently in a transaction.
"""
...
@abc.abstractmethod
def attempt_to_set_autocommit(self, conn: Connection, autocommit: bool):
"""Attempt to set the connections autocommit mode.
When True queries are run outside of transactions.
Note: This has no effect on SQLite3, so callers still need to
commit/rollback the connections.
"""
...