starting a thread in a nother thread
in [Python]
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From: Richard Lamboj on 27 Jan 2010 08:06 hello, just for _curiosity_. What would be if i start a thread in a nother thread and acquire a lock in the "child" thread. Is there anything that could go wrong if someone try to start threads in threads? Kind Regards, Richi
From: Stefan Behnel on 27 Jan 2010 08:10 Richard Lamboj, 27.01.2010 14:06: > just for _curiosity_. What would be if i start a thread in a nother thread and > acquire a lock in the "child" thread. Is there anything that could go wrong > if someone try to start threads in threads? There's usually tons of things that can go wrong w.r.t. threads: http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf However, there's nothing special to a thread that was started from another thread, so the problems don't change. Stefan
From: Richard Lamboj on 27 Jan 2010 09:23 Am Wednesday 27 January 2010 14:10:13 schrieb Stefan Behnel: > Richard Lamboj, 27.01.2010 14:06: > > just for _curiosity_. What would be if i start a thread in a nother > > thread and acquire a lock in the "child" thread. Is there anything that > > could go wrong if someone try to start threads in threads? > > There's usually tons of things that can go wrong w.r.t. threads: > > http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf > > However, there's nothing special to a thread that was started from another > thread, so the problems don't change. > > Stefan Hello, i have tried a little bit around with psycopg2 and threads, I'am sharing one connection for all threads. When i'am starting the threads "normal" everything works without any Problem. When i'am starting the threads from another thread than i got a "segmentation fault" - i'am using locks. I'am sending 2048 Reqeuest at once. The "normal" Methode with one thread for every Request needs 10 seconds. The other Methode starting a thread and starting two other threads from this thread crashes after 10 to 40 requests with the segmentation fault error. Any Idea why? Its a 64 bit maschine. Maybe i'am making something wrong? Kind Regards
From: Stefan Behnel on 27 Jan 2010 09:30 Richard Lamboj, 27.01.2010 15:23: > Am Wednesday 27 January 2010 14:10:13 schrieb Stefan Behnel: >> Richard Lamboj, 27.01.2010 14:06: >>> just for _curiosity_. What would be if i start a thread in a nother >>> thread and acquire a lock in the "child" thread. Is there anything that >>> could go wrong if someone try to start threads in threads? >> There's usually tons of things that can go wrong w.r.t. threads: >> >> http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf >> >> However, there's nothing special to a thread that was started from another >> thread, so the problems don't change. > > i have tried a little bit around with psycopg2 and threads, > > I'am sharing one connection for all threads. When i'am starting the > threads "normal" everything works without any Problem. When i'am starting the > threads from another thread than i got a "segmentation fault" Sounds like a bug that you might want to report to the maintainers of psycopg2. Stefan
From: John Nagle on 27 Jan 2010 16:03
Stefan Behnel wrote: > Richard Lamboj, 27.01.2010 15:23: >> Am Wednesday 27 January 2010 14:10:13 schrieb Stefan Behnel: >>> Richard Lamboj, 27.01.2010 14:06: >>>> just for _curiosity_. What would be if i start a thread in a nother >>>> thread and acquire a lock in the "child" thread. Is there anything that >>>> could go wrong if someone try to start threads in threads? >>> There's usually tons of things that can go wrong w.r.t. threads: >>> >>> http://www.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-1.pdf >>> >>> However, there's nothing special to a thread that was started from another >>> thread, so the problems don't change. >> i have tried a little bit around with psycopg2 and threads, >> >> I'am sharing one connection for all threads. When i'am starting the >> threads "normal" everything works without any Problem. When i'am starting the >> threads from another thread than i got a "segmentation fault" > > Sounds like a bug that you might want to report to the maintainers of psycopg2. > > Stefan If a C package called from Python crashes, the package is defective. Nothing you can do from Python should be able to cause a segmentation fault. Google search: "Results 1 - 10 of about 29,400 for psycopg2 crash". John Nagle |