Re: Pg11 server w/parallel backends unresponsive to cancel/terminate...

John Scalia <jayknowsunix@gmail.com> writes:

> Easiest thing I would do is find that processes PID by querying the
> pg_stat_activity table, then invoke “select from
> pg_terminate_backend(pid#); where of course, you put the determined
> PID from your first query into those parenthesis.

John, none of the backends respond to
pg_(cancel|terminate)_backend(PID)...  as per $subject :-)

Thx


> —
> Jay
>
> Sent from my iPad
>
>> On Sep 11, 2020, at 9:08 AM, Jerry Sievers <gsievers19@comcast.net> wrote:
>>
>> Greetings!  One of my $power users launched big-nasty job on our ~50TB
>> warehouse.
>>
>> Long-running jobs on that box aren't unusual, however this one we want
>> stopped and it's unresponsive to cancel or terminate signalling for
>> several hours.
>>
>> Below are 10 lines captured by running strace over each of the PIDs.
>>
>> What else to look for before we stop-immediate the system?
>>
>> Thx!
>>
>> PS: Will repost w/gdb output as soon as I can remember how to run it for
>> a case like this :-)
>>
>>
>>
>> PostgreSQL 11.7 (Ubuntu 11.7-2.pgdg16.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 5.4.0-6ubuntu1~16.04.12)
5.4.020160609, 64-bit 
>>
>>
>>
>> # echo $#
>> 9
>>
>> # for p; do strace -p $p 2>&1 | head -10; echo; done
>> strace: Process 42079 attached
>> strace: [ Process PID=42079 runs in x32 mode. ]
>> strace: [ Process PID=42079 runs in 64 bit mode. ]
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8219365000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8214364000
>> munmap(0x7f8219365000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81ff856000
>> munmap(0x7f8214364000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81eb855000
>> munmap(0x7f81ff856000, 167776256)       = 0
>>
>> strace: Process 42372 attached
>> strace: [ Process PID=42372 runs in x32 mode. ]
>> strace: [ Process PID=42372 runs in 64 bit mode. ]
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>> munmap(0x7f81fdafb000, 167776256)       = 0
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8219a0b000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8214a0a000
>> munmap(0x7f8219a0b000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>>
>> strace: Process 42373 attached
>> strace: [ Process PID=42373 runs in x32 mode. ]
>> strace: [ Process PID=42373 runs in 64 bit mode. ]
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8217a0a000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8212a09000
>> munmap(0x7f8217a0a000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8212a09000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>>
>> strace: Process 42374 attached
>> strace: [ Process PID=42374 runs in x32 mode. ]
>> strace: [ Process PID=42374 runs in 64 bit mode. ]
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8219a0b000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8214a0a000
>> munmap(0x7f8219a0b000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8214a0a000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>>
>> strace: Process 42375 attached
>> strace: [ Process PID=42375 runs in x32 mode. ]
>> strace: [ Process PID=42375 runs in 64 bit mode. ]
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8219a0b000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8214a0a000
>> munmap(0x7f8219a0b000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8214a0a000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>>
>> strace: Process 42376 attached
>> strace: [ Process PID=42376 runs in x32 mode. ]
>> strace: [ Process PID=42376 runs in 64 bit mode. ]
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8217a0a000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8212a09000
>> munmap(0x7f8217a0a000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8212a09000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>>
>> strace: Process 42377 attached
>> munmap(0x7f81fdafb000, 167776256)       = 0
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8217a0a000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8212a09000
>> munmap(0x7f8217a0a000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8212a09000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>> munmap(0x7f81fdafb000, 167776256)       = 0
>>
>> strace: Process 42378 attached
>> strace: [ Process PID=42378 runs in x32 mode. ]
>> strace: [ Process PID=42378 runs in 64 bit mode. ]
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8214a0a000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>> munmap(0x7f81fdafb000, 167776256)       = 0
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8219a0b000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8214a0a000
>>
>> strace: Process 42379 attached
>> strace: [ Process PID=42379 runs in x32 mode. ]
>> strace: [ Process PID=42379 runs in 64 bit mode. ]
>> munmap(0x7f81e9afa000, 335548416)       = 0
>> mmap(NULL, 41947136, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8217a0a000
>> mmap(NULL, 83890176, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f8212a09000
>> munmap(0x7f8217a0a000, 41947136)        = 0
>> mmap(NULL, 167776256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81fdafb000
>> munmap(0x7f8212a09000, 83890176)        = 0
>> mmap(NULL, 335548416, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f81e9afa000
>>
>>
>>
>>
>> --
>> Jerry Sievers
>> Postgres DBA/Development Consulting
>> e: postgres.consulting@comcast.net
>>
>>
>
>
>

--
Jerry Sievers
Postgres DBA/Development Consulting
e: postgres.consulting@comcast.net