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  1. Percona XtraDB Cluster
  2. PXC-2346

mysqld crashes when executing mysqldump



    • Type: Bug
    • Status: Done
    • Priority: High
    • Resolution: Fixed
    • Affects Version/s: 5.7.24-31.33
    • Fix Version/s: 5.7.25-31.35
    • Component/s: None
    • Labels:
    • Environment:

      I have reproduced this on an Ubuntu 16.04, using the official Percona repositories.


      I have a Galera cluster setup, with the following versions of packages:

      # dpkg -l | grep percona
      ii  percona-toolkit                   3.0.13-1.xenial                            amd64        Advanced MySQL and system command-line tools
      ii  percona-xtrabackup-24             2.4.12-1.xenial                            amd64        Open source backup tool for InnoDB and XtraDB
      ii  percona-xtradb-cluster-5.7-dbg    5.7.24-31.33-1.xenial                      amd64        Debugging package for Percona XtraDB Cluster
      ii  percona-xtradb-cluster-client-5.7 5.7.24-31.33-1.xenial                      amd64        Percona XtraDB Cluster database client binaries
      ii  percona-xtradb-cluster-common-5.7 5.7.24-31.33-1.xenial                      amd64        Percona XtraDB Cluster database common files (e.g. /etc/mysql/my.cnf)
      ii  percona-xtradb-cluster-galera-3.x 3.30-1.xenial                              amd64        Galera components of Percona XtraDB Cluster
      ii  percona-xtradb-cluster-server-5.7 5.7.24-31.33-1.xenial                      amd64        Percona XtraDB Cluster database server binaries

      And when i tried to make a backup i got this:

      # /usr/bin/mysqldump --defaults-file=/etc/mysql/my.cnf  --flush-privileges --hex-blob --opt  --single-transaction --skip-lock-tables --triggers --routines --events   --set-gtid-purged=OFF  --databases mysql  --ignore-table='mysql.innodb_index_stats'  --ignore-table='mysql.innodb_table_stats' > /tmp/backup.sql
      mysqldump: Couldn't execute 'START TRANSACTION /*!40100 WITH CONSISTENT SNAPSHOT */': Lost connection to MySQL server during query (2013)

      in mysqld error log i got this:

      2019-01-09T15:06:34.465906Z 0 [Warning] WSREP: last inactive check more than PT1.5S (3*evs.inactive_check_period) ago (PT2.42045S), skipping check
      15:06:50 UTC - mysqld got signal 11 ;
      This could be because you hit a bug. It is also possible that this binary
      or one of the libraries it was linked against is corrupt, improperly built,
      or misconfigured. This error can also be caused by malfunctioning hardware.
      Attempting to collect some information that could help diagnose the problem.
      As this is a crash and something is definitely wrong, the information
      collection process might fail.
      Please help us make Percona XtraDB Cluster better by reporting any
      bugs at https://jira.percona.com/projects/PXC/issueskey_buffer_size=8388608
      It is possible that mysqld could use up to 
      key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 207558 K  bytes of memory
      Hope that's ok; if not, decrease some variables in the equation.Thread pointer: 0x7f281800bcb0
      Attempting backtrace. You can use the following information to find out
      where mysqld died. If you see no messages after this, something went
      terribly wrong...
      stack_bottom = 7f286c2e0a70 thread_stack 0x40000
      2019-01-09T15:06:50.837627Z 48 [Note] Aborted connection 48 to db: 'information_schema' user: 'MyCMONuser007' host: '' (Got an error reading communication packets)
      2019-01-09T15:06:50.837680Z 8 [Note] Aborted connection 8 to db: 'information_schema' user: 'MyCMONuser007' host: '' (Got an error reading communication packets)
      2019-01-09T15:06:50.837627Z 11 [Note] Aborted connection 11 to db: 'information_schema' user: 'MyCMONuser007' host: '' (Got an error reading communication packets)
      2019-01-09T15:06:50.838210Z 0 [Warning] WSREP: last inactive check more than PT1.5S (3*evs.inactive_check_period) ago (PT13.3721S), skipping check
      2019-01-09T15:06:50.841929Z 0 [Note] InnoDB: page_cleaner: 1000ms intended loop took 13376ms. The settings might not be optimal. (flushed=0, during the time.)
      /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f2901ea041d]Trying to get some variables.
      Some pointers may be invalid and cause the dump to abort.
      Query (7f2818012af0): is an invalid pointer
      Connection ID (thread ID): 56
      Status: NOT_KILLED

      I have also reproduced this with GDB, i have attached the backtrace and my my.cnf as for reference.


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              kenn.takara Kenn Takara
              kedazo David Kedves
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