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  1. MariaDB Server
  2. MDEV-7095

Memory leak in sql_prepare.cc: Prepared_statement::execute_server_runnable()

        Details

        • Type: Bug
        • Status: Open
        • Priority: Minor
        • Resolution: Unresolved
        • Affects Version/s: 10.0
        • Fix Version/s: 10.0
        • Component/s: None
        • Labels:
          None

          Description

          Memory leak at sql_prepare.cc:
          Prepared_statement::execute_server_runnable().

          The memory was leaked because thd->lex was restored at the end of the function.

          The fix is that the lex allocated in this function should delete its explain before the function returns, i.e. Lex's "explain" query statement has to be deleted before restoring saved variables to thd to avoid memory leak.

          Code diff:

            error= server_runnable->execute_server_code(thd);

+  // Lex's "explain" query statement has to be deleted before
+  // restoring saved variables to thd to avoid memory leak.
+  delete_explain_query(lex);
  thd->cleanup_after_query();

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                serg Sergei Golubchik added a comment -

                Interesting. How did you manage to trigger that? As far as I can see this is dead code, it is never executed.

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                serg Sergei Golubchik added a comment - Interesting. How did you manage to trigger that? As far as I can see this is dead code, it is never executed.
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                minli zhu Minli Zhu added a comment -

                It is triggered by calling Ed_connection::execute_direct() from our own code.

                Show
                minli zhu Minli Zhu added a comment - It is triggered by calling Ed_connection::execute_direct() from our own code.

                  People

                  • Assignee:
                    serg Sergei Golubchik
                    Reporter:
                    minli zhu Minli Zhu
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                    Dates

                    • Created:
                      Updated: