Re: [HACKERS] Race conditions in shm_mq.c

2015-08-07 Thread Robert Haas
On Thu, Aug 6, 2015 at 5:59 PM, Antonin Houska a...@cybertec.at wrote: Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 6, 2015 at 2:38 PM, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 6, 2015 at 10:10 AM, Antonin Houska a...@cybertec.at wrote: During my experiments with parallel

Re: [HACKERS] Race conditions in shm_mq.c

2015-08-06 Thread Antonin Houska
Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 6, 2015 at 2:38 PM, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 6, 2015 at 10:10 AM, Antonin Houska a...@cybertec.at wrote: During my experiments with parallel workers I sometimes saw the master and worker process blocked. The

Re: [HACKERS] Race conditions in shm_mq.c

2015-08-06 Thread Robert Haas
On Thu, Aug 6, 2015 at 10:10 AM, Antonin Houska a...@cybertec.at wrote: During my experiments with parallel workers I sometimes saw the master and worker process blocked. The master uses shm queue to send data to the worker, both sides nowait==false. I concluded that the following happened:

Re: [HACKERS] Race conditions in shm_mq.c

2015-08-06 Thread Robert Haas
On Thu, Aug 6, 2015 at 2:38 PM, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 6, 2015 at 10:10 AM, Antonin Houska a...@cybertec.at wrote: During my experiments with parallel workers I sometimes saw the master and worker process blocked. The master uses shm queue to send data to the

[HACKERS] Race conditions in shm_mq.c

2015-08-06 Thread Antonin Houska
During my experiments with parallel workers I sometimes saw the master and worker process blocked. The master uses shm queue to send data to the worker, both sides nowait==false. I concluded that the following happened: The worker process set itself as a receiver on the queue after