poc_max_connections.py

from cassandra.io.eventletreactor import EventletConnection
from cassandra.io.geventreactor import GeventConnection
from cassandra.io.libevreactor import LibevConnection
from cassandra.io.asyncorereactor import AsyncoreConnection

connection_class = AsyncoreConnection

if connection_class == EventletConnection:
    from eventlet import monkey_patch
    monkey_patch()
elif connection_class == GeventConnection:
    import gevent.monkey
    gevent.monkey.patch_all()

from cassandra.cluster import Cluster


import logging
import time

log = logging.getLogger()
log.setLevel('DEBUG')
handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter("%(asctime)s [%(levelname)s] %(name)s: %(message)s"))
log.addHandler(handler)


KEYSPACE = "testkeyspace"

max_in_flight = 2

GeventConnection.max_in_flight = max_in_flight
LibevConnection.max_in_flight = max_in_flight
EventletConnection.max_in_flight = max_in_flight
AsyncoreConnection.max_in_flight = max_in_flight

#Only one cassandra node should be running if we want to reproduce this
cluster = Cluster(['127.0.0.1'], connection_class=connection_class)
session = cluster.connect()

while 1:
    try:
        session.execute("""
            CREATE KEYSPACE IF NOT EXISTS %s
            WITH replication = { 'class': 'SimpleStrategy', 'replication_factor': '2' }
            """ % KEYSPACE)
        session.set_keyspace(KEYSPACE)
        session.execute("""
                        CREATE TABLE IF NOT EXISTS mytable (
                            thekey text,
                            col1 text,
                            col2 text,
                            PRIMARY KEY (thekey, col1)
                        )
                        """)
        session.execute("DROP KEYSPACE " + KEYSPACE)
    except Exception as e:
        logging.error(e, exc_info=True)
        continue
    time.sleep(0.1)