zulip/zerver/lib/db.py

105 lines
2.6 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, bytes, Composable]
Params = Union[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
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: Params = None) -> None:
wrapper_execute(self, super().execute, query, vars)
def executemany(self, query: Query, vars: Iterable[Params]) -> None: # nocoverage
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: Union[str, bytes, None] = ...,
*,
withhold: bool = ...,
scrollable: Optional[bool] = ...,
) -> TimeTrackingCursor:
...
@overload
def cursor(
self,
name: Union[str, bytes, None] = ...,
*,
cursor_factory: Callable[..., CursorT] = ...,
withhold: bool = ...,
scrollable: Optional[bool] = ...,
) -> CursorT:
...
@overload
def cursor(
self,
name: Union[str, bytes, None],
cursor_factory: Callable[..., CursorT] = ...,
withhold: bool = ...,
scrollable: Optional[bool] = ...,
) -> CursorT:
...
def cursor(self, *args: Any, **kwargs: Any) -> cursor:
kwargs["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 = []