[pgpool-general: 4479] Re: Pgpool - connection hangs in DISCARD ALL
Muhammad Usama
m.usama at gmail.com
Mon Feb 22 21:30:49 JST 2016
Hi
I have pushed the above fix in all branches from pgpool-II 3.2 onwards.
http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=6afacb1b19603b37e3d005963182258b9f4fca49
Thanks again for your help in verifying and testing the fix.
Kind regards
Muhammad Usama
On Sat, Feb 20, 2016 at 1:03 AM, Muhammad Usama <m.usama at gmail.com> wrote:
> Hi
>
> Many thanks for the confirmation, the fix needs to go in all branches and
> I will push it in the morning.
>
> Regards
> Muhammad Usama
>
> Sent from my iPhone
>
> > On 19-Feb-2016, at 11:52 PM, Gerhard Wiesinger <lists at wiesinger.com>
> wrote:
> >
> > Hello,
> >
> > Can confirm that this patch worked for me (tested the 3.5 patch
> version), nearly 2 days without any problem. Can you please add it to the
> git repo and make a new release (3.4, 3.5).
> >
> > Thnx.
> >
> > Ciao,
> > Gerhard
> >
> >
> >> On 16.02.2016 11:44, Muhammad Usama wrote:
> >> Hi
> >>
> >> Many thanks for the reply and a good news that you are not getting
> >> stuck connection issue after the patch.
> >>
> >> Thanks
> >> Best regards
> >> Muhammad Usama
> >>
> >>
> >>> On Fri, Feb 12, 2016 at 9:45 PM, Paweł Ufnalewski <archon at foap.com>
> wrote:
> >>> Hmm it looks like it's fine now. Right now I only see these in log:
> >>>
> >>> 2016-02-12 17:28:12: pid 8838: LOG: child process with pid: 27299
> exits
> >>> with status 256
> >>> 2016-02-12 17:28:12: pid 8838: LOG: fork a new child process with
> pid: 6140
> >>> 2016-02-12 17:30:42: pid 8838: LOG: child process with pid: 5571
> exits with
> >>> status 512
> >>> 2016-02-12 17:30:42: pid 8838: LOG: fork a new child process with
> pid: 6720
> >>> 2016-02-12 17:30:43: pid 8838: LOG: child process with pid: 4444
> exits with
> >>> status 512
> >>> 2016-02-12 17:30:43: pid 8838: LOG: fork a new child process with
> pid: 6751
> >>> 2016-02-12 17:35:42: pid 8838: LOG: child process with pid: 6140
> exits with
> >>> status 512
> >>> 2016-02-12 17:35:42: pid 8838: LOG: fork a new child process with
> pid: 7868
> >>> 2016-02-12 17:40:42: pid 8838: LOG: child process with pid: 6751
> exits with
> >>> status 512
> >>> 2016-02-12 17:40:42: pid 8838: LOG: fork a new child process with
> pid: 9018
> >>> 2016-02-12 17:40:42: pid 8838: LOG: child process with pid: 6720
> exits with
> >>> status 512
> >>> 2016-02-12 17:40:42: pid 8838: LOG: fork a new child process with
> pid: 9019
> >>>
> >>> Thank you!
> >>>
> >>> Best regards,
> >>> Paweł Ufnalewski
> >>> Infrastructure Architect at Foap.com
> >>>
> >>> W dniu 2016-02-09 o 14:02, Muhammad Usama pisze:
> >>>
> >>>> Hi
> >>>>
> >>>> Many thanks for sharing the pgpool.log, The log shared by you does
> >>>> contains some error messages "ERROR: unable to to flush data to
> >>>> frontend" that have the potential to cause the stuck connection
> >>>> Can you please try out the attached patch if it fix the problem. I am
> >>>> attaching the patches for both 3_5 and 3_4 branches, please use the
> >>>> respective patch as per your setup. Hopefully this should fix the
> >>>> stuck issue.
> >>>>
> >>>> Kind regards
> >>>> Muhammad Usama
> >>>>
> >>>>
> >>>>
> >>>>> On Mon, Feb 8, 2016 at 8:49 PM, Paweł Ufnalewski <archon at foap.com>
> wrote:
> >>>>> Hi,
> >>>>>
> >>>>> It looks like it hangs in this places (see attachment). Problem
> is,
> >>>>> that
> >>>>> developer responsible for app has changed something in code, so
> >>>>> connections
> >>>>> now closes properly from client side (before I got a lot of these
> errors:
> >>>>>
> >>>>> 2016-02-08 09:33:39: pid 8472: ERROR: unable to read data from
> frontend
> >>>>> 2016-02-08 09:33:39: pid 8472: DETAIL: EOF encountered with
> frontend)
> >>>>> .
> >>>>>
> >>>>> Best regards,
> >>>>> Paweł Ufnalewski
> >>>>> Infrastructure Architect at Foap.com
> >>>>>
> >>>>> W dniu 2016-02-08 o 09:00, Muhammad Usama pisze:
> >>>>>
> >>>>> Hi
> >>>>>
> >>>>> Thanks in advance for the help. If you could share the pgpool-II log
> >>>>> when the stuck connection happens that would help us in identifiny
> and
> >>>>> rectifing the problem.
> >>>>>
> >>>>> Thanks
> >>>>> Best regards
> >>>>> Muhammad Usama
> >>>>>
> >>>>>
> >>>>> On Mon, Feb 8, 2016 at 11:36 AM, Paweł Ufnalewski <archon at foap.com>
> >>>>> wrote:
> >>>>>
> >>>>> Hi,
> >>>>>
> >>>>> just to let you know - I'm having the same problem with 3.4.4
> >>>>> version
> >>>>> (DISCARD ALL appears slower than in 3.4.3 I think, but it still
> does).
> >>>>> How
> >>>>> can I help to fix this problem?
> >>>>>
> >>>>> Best regards,
> >>>>> Paweł Ufnalewski
> >>>>> Infrastructure Architect at Foap.com
> >>>>>
> >>>>> W dniu 2016-02-01 o 08:44, Muhammad Usama pisze:
> >>>>>
> >>>>> Hi Gerhard
> >>>>>
> >>>>> Many thanks for testing and pointing this out. It's unfortunate that
> you
> >>>>> are
> >>>>> still getting the stuck connection issue. If it is possible can you
> >>>>> please
> >>>>> share the pgpool-II log for the time when this stuck connection issue
> >>>>> happens. I am more interested in seeing which exact error message
> that
> >>>>> caused the child process to jump to error handler from where the
> child
> >>>>> process proceeded to send the DISCARD ALL to backend and eventually
> got
> >>>>> stuck. Since after many tries we are not able to reproduce this
> issue, so
> >>>>> log would be really helpful in understanding and fixing the problem.
> >>>>>
> >>>>> Best regards
> >>>>> Muhammad Usama
> >>>>>
> >>>>>
> >>>>> On Sun, Jan 31, 2016 at 9:33 PM, Gerhard Wiesinger <
> lists at wiesinger.com>
> >>>>> wrote:
> >>>>>
> >>>>> On 28.01.2016 01:10, Tatsuo Ishii wrote:
> >>>>>
> >>>>> On 21.01.2016 20:52, Muhammad Usama wrote:
> >>>>>
> >>>>> Hi
> >>>>>
> >>>>> I am looking into this issue. and unfortunately like Ishii-San I am
> >>>>> also not able to reproduce it. But I found one issue in 3.4 that
> might
> >>>>> cause the problem. Can you please try the attached patch if it solves
> >>>>> the problem. Also, if the problem still persists, it would be really
> >>>>> helpful if you could share the pgpool-II log.
> >>>>>
> >>>>> I looked at the patch but it includes only logging changes and no
> >>>>> functional changes. Therefore I didn't test it. Do you expect and
> >>>>> behavioral changes to fix it, and why?
> >>>>>
> >>>>> elog() is not only a logging function, but also it plays very
> >>>>> important role including exception handling and error treatments in
> >>>>> pgpool-II. If you are familiar with PostgreSQL internals, you may
> >>>>> notice it (elog() was imported from PostgreSQL source tree).
> >>>>>
> >>>>> Tried version 3.5.0 where the patch is included. Still not working.
> See
> >>>>> backtrace below.
> >>>>>
> >>>>> Reverting to 3.3.7 which works perfectly.
> >>>>>
> >>>>> Ciao,
> >>>>> Gerhard
> >>>>>
> >>>>> (gdb) back
> >>>>> #0 0x00007fd87fdb6d43 in __select_nocancel () from /lib64/libc.so.6
> >>>>> #1 0x0000564471af16a1 in pool_check_fd (cp=cp at entry=0x564473dfa610)
> at
> >>>>> protocol/pool_process_query.c:635
> >>>>> #2 0x0000564471af1976 in pool_check_fd (cp=cp at entry=0x564473dfa610)
> at
> >>>>> protocol/pool_process_query.c:657
> >>>>> #3 0x0000564471b1f67b in pool_read (cp=0x564473dfa610,
> >>>>> buf=buf at entry=0x7ffc1d71bf97, len=len at entry=1) at
> utils/pool_stream.c:162
> >>>>> #4 0x0000564471af8e6e in read_kind_from_backend
> >>>>> (frontend=frontend at entry=0x564473df3e60,
> >>>>> backend=backend at entry=0x564473df2e00,
> >>>>> decided_kind=decided_kind at entry=0x7ffc1d71c397 "E") at
> >>>>> protocol/pool_process_query.c:3234
> >>>>> #5 0x0000564471affdc9 in ProcessBackendResponse
> >>>>> (frontend=frontend at entry=0x564473df3e60,
> >>>>> backend=backend at entry=0x564473df2e00, state=state at entry
> =0x7ffc1d71c41c,
> >>>>> num_fields=num_fields at entry=0x7ffc1d71c41a) at
> >>>>> protocol/pool_proto_modules.c:2356
> >>>>> #6 0x0000564471af5b15 in pool_process_query
> (frontend=0x564473df3e60,
> >>>>> backend=0x564473df2e00, reset_request=reset_request at entry=1) at
> >>>>> protocol/pool_process_query.c:302
> >>>>> #7 0x0000564471aed98c in backend_cleanup (backend=<optimized out>,
> >>>>> frontend_invalid=frontend_invalid at entry=0 '\000',
> frontend=0x564471e09e40
> >>>>> <child_frontend>)
> >>>>> at protocol/child.c:437
> >>>>> #8 0x0000564471af0637 in do_child (fds=fds at entry=0x564473dee030) at
> >>>>> protocol/child.c:234
> >>>>> #9 0x0000564471ace107 in fork_a_child (fds=0x564473dee030, id=8) at
> >>>>> main/pgpool_main.c:678
> >>>>> #10 0x0000564471aceb6d in reaper () at main/pgpool_main.c:2254
> >>>>> #11 0x0000564471ad322b in PgpoolMain (discard_status=<optimized out>,
> >>>>> clear_memcache_oidmaps=<optimized out>) at main/pgpool_main.c:429
> >>>>> #12 0x0000564471acc7b1 in main (argc=<optimized out>,
> >>>>> argv=0x7ffc1d7219e8)
> >>>>> at main/main.c:310
> >>>>>
> >>>>> #1 0x0000564471af16a1 in pool_check_fd (cp=cp at entry=0x564473dfa610)
> at
> >>>>> protocol/pool_process_query.c:635
> >>>>> 635 fds = select(fd+1, &readmask, NULL,
> &exceptmask,
> >>>>> timeoutp);
> >>>>>
> >>>>> (gdb) print fd
> >>>>> $1 = 8
> >>>>> (gdb) print readmask
> >>>>> $2 = {fds_bits = {256, 0 <repeats 15 times>}}
> >>>>> (gdb) print exceptmask
> >>>>> $3 = {fds_bits = {256, 0 <repeats 15 times>}}
> >>>>> (gdb) print timeoutp
> >>>>> $4 = (struct timeval *) 0x0
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> _______________________________________________
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> >>>>> pgpool-general at pgpool.net
> >>>>> http://www.pgpool.net/mailman/listinfo/pgpool-general
> >> _______________________________________________
> >> pgpool-general mailing list
> >> pgpool-general at pgpool.net
> >> http://www.pgpool.net/mailman/listinfo/pgpool-general
> >
>
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