Limit number of concurrent threads
cmay4 at yahoo.com
Tue Sep 24 20:29:00 CEST 2002
I am writing a database utility that needs to run a particular process
on every table in the database. Currently, it is something like this:
# handle table operations here
for table in all_tables:
# summarize results
Since some tables take much longer than others, and since the table are
not in contention with each other, I'd like to thread the operation.
What I would ideally like is to have a set number of threads, say 10,
running at the same time (my database has a concurrent connection
limit). Since there are about 80 tables, once there are 10 threads
running I'd like to add another one as soon as one finishes. Then I
need to wait at the end until all the threads finish, so that I can
summarize results. One other nice feature would be to exit the
application if any thread fails.
I've searching for examples that fit my problem, and I haven't found
any. Most examples I've found look something like this:
threads = 
for i in range(number_of_tasks):
# let the threads run - just wait for shutdown
for t in threads:
which whould work fine if I wanted to start all 80 threads at once.
I've read about the Queue, but I'm not sure if it's what I want, and I
can't seem to find any good examples on it.
Any help would be appreciated. Thanks.
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