zulip/zerver/lib/db.py

56 lines
2.0 KiB
Python

import time
from psycopg2.extensions import cursor, connection
from psycopg2.sql import Composable
from typing import Callable, Optional, Iterable, Any, Dict, List, Union, TypeVar, \
Mapping, Sequence
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)
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)
def cursor(self, *args: Any, **kwargs: Any) -> TimeTrackingCursor:
kwargs.setdefault('cursor_factory', TimeTrackingCursor)
return connection.cursor(self, *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 = []