Uploaded image for project: 'MariaDB Server'
  1. MariaDB Server
  2. MDEV-26990

DDL_LOG error in the log and errno 168 Unknown (generic) error from engine upon concurrent DDL and DML

    XMLWordPrintable

    Details

      Description

      In the test case below, I don't see any further effects, except for the error on the log and the extra error in SHOW WARNINGS. So, if it's innocent, it's just a cosmetic issue (should probably be a warning in the log and nothing at all in the client), and then it would be Minor.
      However, in stress tests I see similar DDL_LOG errors in connection with corruption-like outcome, with errors like "table doesn't exist in engine". It can be a coincidence or can be a real relation, in the latter case as a corruption it would probably be Critical.
      So, I will keep it Major for now, as a middle ground. Please adjust according to results of the analysis.

      The test case is highly non-deterministic, but it's fast, so run with a big enough --repeat-N. On my machine, it usually fails within 50-100 attempts, but it can vary on different machines and builds.

      --source include/have_innodb.inc
       
      CREATE TABLE t1 (pk INT AUTO_INCREMENT PRIMARY KEY, f INT) ENGINE=InnoDB;
      INSERT INTO t1 (f) VALUES (1),(2),(3),(4),(5);
      CREATE TABLE t2 (pk INT AUTO_INCREMENT PRIMARY KEY, f INT, FOREIGN KEY (pk) REFERENCES t1(pk)) ENGINE=InnoDB;
      SET innodb_lock_wait_timeout= 0;
      START TRANSACTION;
       
      --connect (con1,localhost,root,,test)
      SET innodb_lock_wait_timeout= 0;
      --send
        RENAME TABLE t1 TO tmp1, tmp1 TO tmp2, tmp2 TO t1;
       
      --connection default
      --error 0,ER_LOCK_WAIT_TIMEOUT
      INSERT INTO t2 (f) VALUES (1),(2),(3),(4),(5);
       
      --connection con1
      --error 0,ER_LOCK_WAIT_TIMEOUT
      --reap
      SHOW WARNINGS;
      --error 0,1
      --exec grep DDL_LOG $MYSQLTEST_VARDIR/log/mysqld.1.err
      if ($sys_errno == 0)
      {
        --die # Found DDL_LOG error in the log
      }
       
      --connection default
      DROP TABLE t2, t1;
      

      bb-10.6-release 109fc67d4

      SHOW WARNINGS;
      Level	Code	Message
      Error	1205	Lock wait timeout exceeded; try restarting transaction
      Error	1025	Error on rename of './test/tmp1' to './test/tmp2' (errno: 168 "Unknown (generic) error from engine")
      Error	1205	Lock wait timeout exceeded; try restarting transaction
      

      2021-11-07 18:02:10 220 [ERROR] DDL_LOG: Got error 1205 when trying to execute action for entry 1 of type 'rename table'
      

      Reproducible on 10.6-10.7.

        Attachments

          Activity

            People

            Assignee:
            marko Marko Mäkelä
            Reporter:
            elenst Elena Stepanova
            Votes:
            0 Vote for this issue
            Watchers:
            1 Start watching this issue

              Dates

              Created:
              Updated:

                Git Integration

                Error rendering 'com.xiplink.jira.git.jira_git_plugin:git-issue-webpanel'. Please contact your Jira administrators.