ref: 5f7a6b7ea3c4ae1b51beffe3309e9b6b0491e71f
dir: /sys/src/cmd/python/Doc/lib/sqlite3/countcursors.py/
import sqlite3 class CountCursorsConnection(sqlite3.Connection): def __init__(self, *args, **kwargs): sqlite3.Connection.__init__(self, *args, **kwargs) self.numcursors = 0 def cursor(self, *args, **kwargs): self.numcursors += 1 return sqlite3.Connection.cursor(self, *args, **kwargs) con = sqlite3.connect(":memory:", factory=CountCursorsConnection) cur1 = con.cursor() cur2 = con.cursor() print con.numcursors