Re: [Jython-dev] Jython 2.7.1 became unusable because of multithreading issues with regexps

[Jeff A. <ja...@fa...>]

Working with Ivan's demonstration, and a more stressful version (see 
tickethttp://bugs.jython.org/issue2609), I was unable to reproduce the 
problem on my main dev box (Windows 10).

I'm thinking hardware multiprocessing might be a factor.  Anyone with 
lots of CPUs (and a different OS) like to take this on?

Jeff


On 22/07/2017 09:01, Ivan Ponomarev via Jython-dev wrote:
> Hello all!
>
> We are using jython heavily from Java application in multiple threads. 
> This didn't cause any problems in 2.7.1b3 and earlier versions.
>
> After upgrading to 2.7.1 we faced the following:  a simple call to 
> datetime.strptime(...) or json.loads(...) can lead to 
> "'org.python.modules.sre.MatchObject' object has no attribute..." error.
>
> As I suspect, this is related to the fact that RegexObject is not 
> thread-safe anymore. It never was in Java, and never promised to be in 
> Python, though in earlier versions of Jython this was possible:
>
> ##############################################
> import thread
> import re
> import time
> REGEX = re.compile('((?:foo|bar)+)(\d*)E?')
>
> def parse(line):
>   m = REGEX.search(line)
>   if m.groups():
>     print m.group(1)
>
> thread.start_new_thread(parse,('foofoofoofoofoofoofoofoofoo234',))
> thread.start_new_thread(parse, ('foobarbarbarbarbarbarbarfoo4E',))
> ....
> thread.start_new_thread(parse, ('foobarbarbarbarbarbarbarfoo4E',))
> time.sleep(1)
> ###############################################
>
> In Jython 2.7.1 this (sometimes! you might need to run this script a 
> couple of times) cause "'MatchObject' object has no attribute" errors.
>
> Instead of calling shared RegexObject one can simply do this:
>
> def printtime(time):
>   print datetime.datetime.strptime(time, '%Y-%m-%dT%H:%M:%S')
> thread.start_new_thread(printtime, ('2017-07-01T11:11:11',))
> ...
> thread.start_new_thread(printtime, ('2017-07-01T11:11:11',))
>
>
> The same with json.loads.
>
> OK, we never share RegexObjects between threads in our code. But we 
> cannot refuse to use json.loads and datetime.strptime!
>
> This became a major issue for us (http://bugs.jython.org/issue2609). 
> What would you suggest? How can we help to solve this?
>
> Regards,
>
> Ivan Ponomarev
>
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