Dictionary inserts and threads

[Martin P. Hellwig]

Hi all,

I'm thinking to speed up a process, I like to use multiple threads to
get data fractions from multiple servers and place those data fragments
into a local dictionary for further processing, the dictionary will look
like this:

self.dic = {'thread_a':dict(),
'thread_b':dict()}

The fragments will not overlap each other, since they will be
subdictionaries within the dictionary, though it would be possible that
multiple threads do something like this at the same time:

self.dic['thread_a'] = data_from_a()
and
self.dic['thread_b'] = data_from_b()

I assume that this is not a problem, but since assuming something gives
a lot of room for screw-ups I rather ask beforehand if I should except
all kinds of troubles when multiple threads update 'at the same time' a
dictionary or that I should lock the dictionary, for each update?

Thanks for your insights.

 

[Paul Rubin]

I assume that this is not a problem, but since assuming something
gives a lot of room for screw-ups I rather ask beforehand if I should
except all kinds of troubles when multiple threads update 'at the same
time' a dictionary or that I should lock the dictionary, for each
update?

Use a lock, or serialize the updates through a queue.