zulip/zerver/lib/db.py

55 lines
1.7 KiB
Python

import time
from collections.abc import Callable, Iterable, Mapping, Sequence
from typing import Any, TypeAlias, TypeVar
from psycopg2.extensions import connection, cursor
from psycopg2.sql import Composable
from typing_extensions import override
CursorObj = TypeVar("CursorObj", bound=cursor)
Query: TypeAlias = str | bytes | Composable
Params: TypeAlias = Sequence[object] | Mapping[str, object] | None
ParamsT = TypeVar("ParamsT")
# Similar to the tracking done in Django's CursorDebugWrapper, but done at the
# psycopg2 cursor level so it works with SQLAlchemy.
def wrapper_execute(
self: CursorObj, action: Callable[[Query, ParamsT], None], sql: Query, params: ParamsT
) -> None:
start = time.time()
try:
action(sql, params)
finally:
stop = time.time()
duration = stop - start
assert isinstance(self.connection, TimeTrackingConnection)
self.connection.queries.append(
{
"time": f"{duration:.3f}",
}
)
class TimeTrackingCursor(cursor):
"""A psycopg2 cursor class that tracks the time spent executing queries."""
@override
def execute(self, query: Query, vars: Params = None) -> None:
wrapper_execute(self, super().execute, query, vars)
@override
def executemany(self, query: Query, vars_list: Iterable[Params]) -> None: # nocoverage
wrapper_execute(self, super().executemany, query, vars_list)
CursorT = TypeVar("CursorT", bound=cursor)
class TimeTrackingConnection(connection):
"""A psycopg2 connection class that uses TimeTrackingCursors."""
def __init__(self, *args: Any, **kwargs: Any) -> None:
self.queries: list[dict[str, str]] = []
super().__init__(*args, **kwargs)