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  1. Percona XtraDB Cluster
  2. PXC-3131

Percona xtradb gets into a state where mysqld freezes

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    Details

    • Type: Bug
    • Status: Done
    • Priority: Medium
    • Resolution: Cannot Reproduce
    • Affects Version/s: 5.7.x
    • Fix Version/s: None
    • Component/s: Support Request
    • Labels:
    • Environment:

      Description

      PXC 5.7.16-10-57-log run standalone, freezes up.

       

      I understand this is an old version of PXC, so I'm not so much expecting a fix as just hoping someone could shed some light on the issue.

       

      Initially clients trying to connect just hang on connect, strace:

       

      accept(29, {sa_family=AF_LOCAL, NULL}, [2]) = 1000 fcntl(1000, F_SETFD, FD_CLOEXEC) = 0 mmap(NULL, 204800, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_STACK, -1, 0) = 0x7f91e1829000 mprotect(0x7f91e1829000, 4096, PROT_NONE) = 0 clone(child_stack=0x7f91e1859eb0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tidptr=0x7f91e185a9d0, tls=0x7f91e185a700, child_tidptr=0x7f91e185a9d0) = 29451 poll([{fd=24, events=POLLIN}, {fd=29, events=POLLIN}], 2, 4294967295) = 1 ([{fd=24, revents=POLLIN}])

       

      ... after a while the hangs stop and we start getting a "Too Many Connections" response, strace:

       

      accept(24, {sa_family=AF_INET6, sin6_port=htons(43936), inet_pton(AF_INET6, "::ffff:127.0.0.1", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 1055
      fcntl(1055, F_SETFD, FD_CLOEXEC)        = 0
      setsockopt(1055, SOL_TCP, TCP_NODELAY, [1], 4) = 0
      sendto(1055, "\27\0\0\0\377\20\4Too many connections", 27, MSG_DONTWAIT, NULL, 0) = 27
      shutdown(1055, SHUT_RDWR)               = 0
      close(1055)                             = 0
      write(2, "2020-04-01T08:13:51.059685Z 0 [W"..., 61) = 61
      poll([{fd=24, events=POLLIN}, {fd=29, events=POLLIN}], 2, 4294967295) = 1 ([{fd=24, revents=POLLIN}])

       

      I'm aware there's not much to go on here, I'm fishing for leads to investigate further.

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              Assignee:
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              Reporter:
              glynastill Glyn Astill
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