synapse-product/synapse/storage/engines/sqlite.py
Erik Johnston fa8934b175 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 17:08:58 +01:00

142 lines
4.6 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 struct
import threading
import typing
from synapse.storage.engines import BaseDatabaseEngine
from synapse.storage.types import Connection
if typing.TYPE_CHECKING:
import sqlite3 # noqa: F401
class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
def __init__(self, database_module, database_config):
super().__init__(database_module, database_config)
database = database_config.get("args", {}).get("database")
self._is_in_memory = database in (None, ":memory:",)
# The current max state_group, or None if we haven't looked
# in the DB yet.
self._current_state_group_id = None
self._current_state_group_id_lock = threading.Lock()
@property
def single_threaded(self) -> bool:
return True
@property
def can_native_upsert(self):
"""
Do we support native UPSERTs? This requires SQLite3 3.24+, plus some
more work we haven't done yet to tell what was inserted vs updated.
"""
return self.module.sqlite_version_info >= (3, 24, 0)
@property
def supports_tuple_comparison(self):
"""
Do we support comparing tuples, i.e. `(a, b) > (c, d)`? This requires
SQLite 3.15+.
"""
return self.module.sqlite_version_info >= (3, 15, 0)
@property
def supports_using_any_list(self):
"""Do we support using `a = ANY(?)` and passing a list
"""
return False
def check_database(self, db_conn, allow_outdated_version: bool = False):
if not allow_outdated_version:
version = self.module.sqlite_version_info
if version < (3, 11, 0):
raise RuntimeError("Synapse requires sqlite 3.11 or above.")
def check_new_database(self, txn):
"""Gets called when setting up a brand new database. This allows us to
apply stricter checks on new databases versus existing database.
"""
def convert_param_style(self, sql):
return sql
def on_new_connection(self, db_conn):
# We need to import here to avoid an import loop.
from synapse.storage.prepare_database import prepare_database
if self._is_in_memory:
# In memory databases need to be rebuilt each time. Ideally we'd
# reuse the same connection as we do when starting up, but that
# would involve using adbapi before we have started the reactor.
prepare_database(db_conn, self, config=None)
db_conn.create_function("rank", 1, _rank)
db_conn.execute("PRAGMA foreign_keys = ON;")
db_conn.commit()
def is_deadlock(self, error):
return False
def is_connection_closed(self, conn):
return False
def lock_table(self, txn, table):
return
@property
def server_version(self):
"""Gets a string giving the server version. For example: '3.22.0'
Returns:
string
"""
return "%i.%i.%i" % self.module.sqlite_version_info
def in_transaction(self, conn: Connection) -> bool:
return conn.in_transaction # type: ignore
def attempt_to_set_autocommit(self, conn: Connection, autocommit: bool):
# Twisted doesn't let us set attributes on the connections, so we can't
# set the connection to autocommit mode.
pass
# Following functions taken from: https://github.com/coleifer/peewee
def _parse_match_info(buf):
bufsize = len(buf)
return [struct.unpack("@I", buf[i : i + 4])[0] for i in range(0, bufsize, 4)]
def _rank(raw_match_info):
"""Handle match_info called w/default args 'pcx' - based on the example rank
function http://sqlite.org/fts3.html#appendix_a
"""
match_info = _parse_match_info(raw_match_info)
score = 0.0
p, c = match_info[:2]
for phrase_num in range(p):
phrase_info_idx = 2 + (phrase_num * c * 3)
for col_num in range(c):
col_idx = phrase_info_idx + (col_num * 3)
x1, x2 = match_info[col_idx : col_idx + 2]
if x1 > 0:
score += float(x1) / x2
return score