anonymousland-synapse/synapse/storage/engines/postgres.py
Mark Haines d5fb561709 Optionally make committing to postgres asynchronous.
Useful when running tests when you don't care whether the server
will lose data that it claims that it has committed.
2016-06-20 17:53:38 +01:00

65 lines
2.4 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.
from ._base import IncorrectDatabaseSetup
class PostgresEngine(object):
single_threaded = False
def __init__(self, database_module, database_config):
self.module = database_module
self.module.extensions.register_type(self.module.extensions.UNICODE)
self.synchronous_commit = database_config.get("synchronous_commit", True)
def check_database(self, txn):
txn.execute("SHOW SERVER_ENCODING")
rows = txn.fetchall()
if rows and rows[0][0] != "UTF8":
raise IncorrectDatabaseSetup(
"Database has incorrect encoding: '%s' instead of 'UTF8'\n"
"See docs/postgres.rst for more information."
% (rows[0][0],)
)
def convert_param_style(self, sql):
return sql.replace("?", "%s")
def on_new_connection(self, db_conn):
db_conn.set_isolation_level(
self.module.extensions.ISOLATION_LEVEL_REPEATABLE_READ
)
# Asynchronous commit, don't wait for the server to call fsync before
# ending the transaction.
# https://www.postgresql.org/docs/current/static/wal-async-commit.html
if not self.synchronous_commit:
cursor = db_conn.cursor()
cursor.execute("SET synchronous_commit TO OFF")
cursor.close()
def is_deadlock(self, error):
if isinstance(error, self.module.DatabaseError):
# https://www.postgresql.org/docs/current/static/errcodes-appendix.html
# "40001" serialization_failure
# "40P01" deadlock_detected
return error.pgcode in ["40001", "40P01"]
return False
def is_connection_closed(self, conn):
return bool(conn.closed)
def lock_table(self, txn, table):
txn.execute("LOCK TABLE %s in EXCLUSIVE MODE" % (table,))