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

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. 
—
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
>
>