Re: cygserver - Postgres Multiple connection Load Testing - Inifinte Loop

[Marco Atzeri <marco.atzeri@gmail.com>]

On 07/05/2017 05:47, Larry Hall (Cygwin) wrote:
> On 05/06/2017 11:27 PM, Noah Misch wrote:
>> On Sat, Apr 01, 2017 at 10:36:24PM -0400, Noah Misch wrote:
>>> On Tue, Mar 28, 2017 at 01:26:52AM -0400, Noah Misch wrote:
>>>> On Fri, Mar 24, 2017 at 06:11:01PM +0100, Corinna Vinschen wrote:
>>>>> I pushed a patchset now, and uploaded new developer snapshots for
>>>>> testing to https://cygwin.com/snapshots/
>>>>
>>>>> Please give it a try
>>>
>>>> I call the cygwin-20170324 freezes "limited" because the symptoms
>>>> differ from
>>>> the classic freeze I described upthread.  "strace /bin/true" and "cat
>>>> /proc/sysvipc/sem" do not hang, but every PostgreSQL backend process
>>>> is stuck
>>>> waiting on a synchronization primitive.
>>>>
>>>> I can distill another self-contained test case for the limited
>>>> freeze seen in
>>>> cygwin-20170324, but that make take awhile.  I'm sending this early
>>>> report so
>>>> you're aware of the possible regression in cygwin-20170324.
>>>
>>> I'm attaching a new test program that demonstrates the regression.
>>> My previous
>>> test program created sixteen processes that each picked a random
>>> semaphore to
>>> lock.  Now, each process picks two semaphores and locks them in
>>> order.  This
>>> proceeds smoothly on GNU/Linux and on cygwin-20170321.tar.xz
>>> "cygserver -r 40".
>>> It freezes within one second on cygwin-20170324.tar.xz "cygserver -r
>>> 40".
>>
>> I suggest reverting the cygwin-20170324 cygserver changes for now.  Older
>> versions can be configured to have reliable sysv semaphores, but I
>> think no
>> settings render sysv semaphores reliable in Cygwin 2.8.0.  What do you
>> think?
>
> Just FYI, Corinna is away for a bit (in European time, "a bit" = until
> June ;-) ) so don't be surprised if her response is delayed.
>

as she is back, we can humble rise her attention to the matter.

Regards
Marco



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