问题
I'm trying to pass a mysql connection to a thread in python. If i do the initialization of the mysql inside the worker class, there is no error.
However, it might be costly for the connection so I tried just passing the mysql connection from the caller function (see code below). But this keeps throwing this error:
(2006, "MySQL server has gone away (BrokenPipeError(32, 'Broken pipe'))
Any idea why? I think its because the way we pass the mysql connection
def worker(db):
""" Distributes the workload for a thread
"""
while True:
item = queue_handler.get()
perform_insert(item, db)
queue_handler.task_done()
def insert_bulk(params):
""" Handles the insert
"""
cntr = 0
res = []
cannot_read = []
(data, cms, report_id) = params
db = nmi_mysql.DB(CONFIG['earnings_db'], True)
for i in range(10):
thrd = threading.Thread(target=worker, args=(db,))
thrd.deamon = True
thrd.start()
for row in data:
split_files = row.split(',')
if len(split_files) != 34:
cannot_read.append(split_files)
continue
now = datetime.datetime.now()
res.append(<some data to insert>)
if len(res) == 750 or cntr == len(data):
queue_handler.put([res, cms, report_id])
res = []
cntr += 1
queue_handler.join()
db.close()
return [len(res), cms]
UPDATE
Instead of passing the mysql connection, we created a connection pool and use that pool in the threads. This way, we just get connection from the pool on the thread level.
回答1:
Database connections are not thread safe, so you shouldn't pass them from one thread to another. A connection pool holds onto open connections between requests, so it's faster to get a connection from the pool, use it for a query, and then release it.
This related answer has some useful links on the thread safety of database connections.
来源:https://stackoverflow.com/questions/33228743/getting-broken-pipe-when-passing-mysql-connection-to-a-python-thread