zulip/zerver/lib/db.py

95 lines
2.4 KiB
Python

import time
from typing import (
Any,
Callable,
Dict,
Iterable,
List,
Mapping,
Optional,
Sequence,
TypeVar,
Union,
overload,
)
from psycopg2.extensions import connection, cursor
from psycopg2.sql import Composable
CursorObj = TypeVar("CursorObj", bound=cursor)
Query = Union[str, Composable]
Params = Union[Sequence[object], Mapping[str, object]]
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], CursorObj], sql: Query, params: ParamsT
) -> CursorObj:
start = time.time()
try:
return action(sql, params)
finally:
stop = time.time()
duration = stop - start
self.connection.queries.append(
{
"time": f"{duration:.3f}",
}
)
class TimeTrackingCursor(cursor):
"""A psycopg2 cursor class that tracks the time spent executing queries."""
def execute(self, query: Query, vars: Optional[Params] = None) -> "TimeTrackingCursor":
return wrapper_execute(self, super().execute, query, vars)
def executemany(
self, query: Query, vars: Iterable[Params]
) -> "TimeTrackingCursor": # nocoverage
return wrapper_execute(self, super().executemany, query, vars)
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)
@overload
def cursor(
self,
name: str = ...,
*,
scrollable: Optional[bool] = ...,
withhold: bool = ...,
) -> TimeTrackingCursor:
...
@overload
def cursor(
self,
name: str = ...,
cursor_factory: Callable[..., CursorT] = ...,
scrollable: Optional[bool] = ...,
withhold: bool = ...,
) -> CursorT:
...
def cursor(self, *args: object, **kwargs: object) -> cursor:
kwargs.setdefault("cursor_factory", TimeTrackingCursor)
return super().cursor(*args, **kwargs)
def reset_queries() -> None:
from django.db import connections
for conn in connections.all():
if conn.connection is not None:
conn.connection.queries = []