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  1. MariaDB Server
  2. MDEV-21269

Parallel merging of fts index rebuild fails

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      Description

      While issuing ALTER on a InnoDB table with FTS MariaDB breaks with a segmentation fault:

      kernel: mysqld[812]: segfault at 0 ip 00005649f0b31ac8 sp 00007febffffd0b0 error 6 in mysqld[5649efe3e000+12c9000]

      MariaDB [test]> optimize table t;
      -----------------------------------------------------------------------------------------+

      Table Op Msg_type Msg_text

      -----------------------------------------------------------------------------------------+

      test.t optimize note Table does not support optimize, doing recreate + analyze instead
      test.t optimize status OK

      -----------------------------------------------------------------------------------------+
      2 rows in set (10.312 sec)

      MariaDB [test]> optimize table t;
      -----------------------------------------------------------------------------------------+

      Table Op Msg_type Msg_text

      -----------------------------------------------------------------------------------------+

      test.t optimize note Table does not support optimize, doing recreate + analyze instead
      test.t optimize status OK

      -----------------------------------------------------------------------------------------+
      2 rows in set (6.379 sec)

      MariaDB [test]> optimize table t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query
      MariaDB [test]> optimize table t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query
      MariaDB [test]> optimize table t;
      ERROR 2013 (HY000): Lost connection to MySQL server during query

      We managed to replicate this after around 3 consecutive calls of ALTER TABLE t ENGINE=InnoDB; after the initial data import.

      If we remove the FTS index there are no more issues.
      It seems the issue appears on FTS index merge, recreate.

      I've attached to this ticket the backtrace, MariaDB log, configuration and sample data used to replicate the issue.

      If you require any additional info, just let me know.

        Attachments

        1. backtrace.txt
          79 kB
          Ovidiu Stanila
        2. mariadb.log
          4 kB
          Ovidiu Stanila
        3. my.cnf
          1 kB
          Ovidiu Stanila
        4. t.sql.gz
          5.16 MB
          Ovidiu Stanila

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              Assignee:
              thiru Thirunarayanan Balathandayuthapani
              Reporter:
              ovidiu.stanila Ovidiu Stanila
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                Created:
                Updated:
                Resolved: