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  1. MariaDB Server
  2. MDEV-4352

multi_source replication: conflict between rli->slave_patternload_file files of different connections

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 10.0.1
    • Fix Version/s: 10.0.2, 10.0.3
    • Component/s: None
    • Labels:

      Description

      When using multiple connections to different masters in a slave server, there
      is nothing done to guard against conflicts on the file name constructed in
      rli->slave_patternload_file.

      I found this from random failures in a test case where I start two slave
      connections at once:

      CHANGE MASTER 'slave1' TO master_port=$SERVER_MYPORT_1,
          master_host='127.0.0.1', master_user='root';
      CHANGE MASTER 'slave2' TO master_port=$SERVER_MYPORT_2,
           master_host='127.0.0.1', master_user='root';
      start all slaves;
      

      This results sometimes in this error:

      130329 21:18:13 [ERROR] Master 'slave1': Slave SQL: Unable to use slave's temporary directory /private/var/lib/buildslave/maria-slave/labrador/build/mysql-test/var/tmp/mysqld.3 - Can't create/write to file '/private/var/lib/buildslave/maria-slave/labrador/build/mysql-test/var/tmp/mysqld.3/SQL_LOAD-' (Errcode: 17 "File exists"), Error_code: 1
      

      This happens because both SQL threads call
      check_temp_dir(rli->slave_patternload_file) on the same file name created in
      init_relay_log_info().

      I think there are more problems with this. For example, it looks like
      cleanup_load_tmpdir() could easily wrongly remove files from a different
      connection. There seems nothing done to handle temporary files correctly
      between different connections to multiple masters.

      This seems like something that could easily cause silent (or not so silent)
      corruption of replication.

        Gliffy Diagrams

          Activity

          Hide
          elenst Elena Stepanova added a comment -

          See also MDEV-4033

          Show
          elenst Elena Stepanova added a comment - See also MDEV-4033
          Hide
          monty Michael Widenius added a comment -

          The issue with check_temp_dir() is already fixed in 10.0.2
          I will look at fixing cleanup_load_tmpdir() for 10.0.3

          Show
          monty Michael Widenius added a comment - The issue with check_temp_dir() is already fixed in 10.0.2 I will look at fixing cleanup_load_tmpdir() for 10.0.3
          Hide
          monty Michael Widenius added a comment -

          There was also a bug that two parallel LOAD DATA statements could use the same temporary file name.
          I fixed this by prefixing the temporary file name with the connection name.

          Show
          monty Michael Widenius added a comment - There was also a bug that two parallel LOAD DATA statements could use the same temporary file name. I fixed this by prefixing the temporary file name with the connection name.
          Hide
          monty Michael Widenius added a comment -

          Pushed into 10.0-base tree

          Show
          monty Michael Widenius added a comment - Pushed into 10.0-base tree

            People

            • Assignee:
              monty Michael Widenius
              Reporter:
              knielsen Kristian Nielsen
            • Votes:
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              Watchers:
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              Dates

              • Created:
                Updated:
                Resolved: