anonymousland-synapse/synapse/storage/engines/sqlite.py
Sean Quah 6d14fdc271
Make sqlite database migrations transactional again, part two (#14926)
#14910 fixed the regression introduced by #13873 where sqlite database
migrations would no longer run inside a transaction. However, it
committed the transaction before Synapse updated its bookkeeping of
which migrations have been run, which means that migrations may be run
again after they have completed successfully.

Leave the transaction open at the end of `executescript`, to restore the
old, correct behaviour. Also make the PostgreSQL behaviour consistent
with SQLite.

Fixes #14909.

Signed-off-by: Sean Quah <seanq@matrix.org>
2023-01-31 11:03:55 +00:00

173 lines
6.4 KiB
Python

# 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 platform
import sqlite3
import struct
import threading
from typing import TYPE_CHECKING, Any, List, Mapping, Optional
from synapse.storage.engines import BaseDatabaseEngine
from synapse.storage.types import Cursor
if TYPE_CHECKING:
from synapse.storage.database import LoggingDatabaseConnection
class Sqlite3Engine(BaseDatabaseEngine[sqlite3.Connection, sqlite3.Cursor]):
def __init__(self, database_config: Mapping[str, Any]):
super().__init__(sqlite3, database_config)
database = database_config.get("args", {}).get("database")
self._is_in_memory = database in (
None,
":memory:",
)
if platform.python_implementation() == "PyPy":
# pypy's sqlite3 module doesn't handle bytearrays, convert them
# back to bytes.
sqlite3.register_adapter(bytearray, lambda array: bytes(array))
# 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 supports_using_any_list(self) -> bool:
"""Do we support using `a = ANY(?)` and passing a list"""
return False
@property
def supports_returning(self) -> bool:
"""Do we support the `RETURNING` clause in insert/update/delete?"""
return sqlite3.sqlite_version_info >= (3, 35, 0)
def check_database(
self, db_conn: sqlite3.Connection, allow_outdated_version: bool = False
) -> None:
if not allow_outdated_version:
# Synapse is untested against older SQLite versions, and we don't want
# to let users upgrade to a version of Synapse with broken support for their
# sqlite version, because it risks leaving them with a half-upgraded db.
if sqlite3.sqlite_version_info < (3, 27, 0):
raise RuntimeError("Synapse requires sqlite 3.27 or above.")
def check_new_database(self, txn: Cursor) -> None:
"""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: str) -> str:
return sql
def on_new_connection(self, db_conn: "LoggingDatabaseConnection") -> None:
# 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;")
# Enable WAL.
# see https://www.sqlite.org/wal.html
db_conn.execute("PRAGMA journal_mode = WAL;")
db_conn.commit()
def is_deadlock(self, error: Exception) -> bool:
return False
def is_connection_closed(self, conn: sqlite3.Connection) -> bool:
return False
def lock_table(self, txn: Cursor, table: str) -> None:
return
@property
def server_version(self) -> str:
"""Gets a string giving the server version. For example: '3.22.0'."""
return "%i.%i.%i" % sqlite3.sqlite_version_info
def in_transaction(self, conn: sqlite3.Connection) -> bool:
return conn.in_transaction
def attempt_to_set_autocommit(
self, conn: sqlite3.Connection, autocommit: bool
) -> None:
# Twisted doesn't let us set attributes on the connections, so we can't
# set the connection to autocommit mode.
pass
def attempt_to_set_isolation_level(
self, conn: sqlite3.Connection, isolation_level: Optional[int]
) -> None:
# All transactions are SERIALIZABLE by default in sqlite
pass
@staticmethod
def executescript(cursor: sqlite3.Cursor, script: str) -> None:
"""Execute a chunk of SQL containing multiple semicolon-delimited statements.
Python's built-in SQLite driver does not allow you to do this with DBAPI2's
`execute`:
> execute() will only execute a single SQL statement. If you try to execute more
> than one statement with it, it will raise a Warning. Use executescript() if
> you want to execute multiple SQL statements with one call.
The script is prefixed with a `BEGIN TRANSACTION`, since the docs for
`executescript` warn:
> If there is a pending transaction, an implicit COMMIT statement is executed
> first. No other implicit transaction control is performed; any transaction
> control must be added to sql_script.
"""
# The implementation of `executescript` can be found at
# https://github.com/python/cpython/blob/3.11/Modules/_sqlite/cursor.c#L1035.
cursor.executescript(f"BEGIN TRANSACTION; {script}")
# Following functions taken from: https://github.com/coleifer/peewee
def _parse_match_info(buf: bytes) -> List[int]:
bufsize = len(buf)
return [struct.unpack("@I", buf[i : i + 4])[0] for i in range(0, bufsize, 4)]
def _rank(raw_match_info: bytes) -> float:
"""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