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  1. MariaDB Connector/C
  2. CONC-301

Using mysql_stmt_bind_result() in prepared queries

Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 3.0.0, 3.0.1, 3.0.2, 2.3.4, 3.0.3
    • 3.0.3, 2.3.5
    • None
    • Ubuntu 17.10, gcc 7, compiling from source

    Description

      The test for CONC-281 contains no call to mysql_stmt_bind_result(), adding it breaks the test: https://github.com/krlmlr/mariadb-connector-c/tree/b-test-string-constant. However, this seems to be the recommended way to find out the length of the data if it is not known beforehand: https://dev.mysql.com/doc/refman/5.7/en/mysql-stmt-fetch.html

      The problem seems to be present in 2.3.4 and in the 3.0 branch, and it carries over to RMariaDB. I have a patch that removes the call to mysql_stmt_bind_result(), it works with the current master of Connector/C but fails with everything else:

      1. master of RMariaDB:

      • works with libmysqlclient
      • works with libmariadbclient 2.3.4
      • breaks with current libmariadbclient 3.0.x

      2. patched RMariaDB, https://github.com/r-dbi/RMariaDB/pull/81:

      • breaks with libmysqlclient
      • breaks with libmariadbclient 2.3.4
      • works with current libmariadbclient 3.0.x

      I haven't found anything related to this change in the release notes. Please advise.

      For the future: Would you consider adding tests for RMariaDB compiled against your latest development versions to your automated test system? This will ensure smooth operation of RMariaDB, and also adds another rich test suite for Connector/C.

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. MDEV-17116 After upgrade from 10.1.35 to 10.3.9, SELECT query in prepared statement does not write in provided buffer

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. CONC-281 mysql_stmt_fetch_column() should work without mysql_stmt_store_result()

          • Major - Major loss of function.
          • Closed

          Activity

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            georg Georg Richter added a comment -

            Hi Kirill,

            issue confirmed:

            The correct statement status (MYSQL_STMT_USER_FETCHING) is set after fetch_to_bind, so in case fetch_to_bind fails with truncation the status is not updated correctly and subsequent calls to mysql_stmt_fetch_column will fail.

            georg Georg Richter added a comment - Hi Kirill, issue confirmed: The correct statement status ( MYSQL_STMT_USER_FETCHING ) is set after fetch_to_bind , so in case fetch_to_bind fails with truncation the status is not updated correctly and subsequent calls to mysql_stmt_fetch_column will fail.
            krlmlr Kirill Müller added a comment -

            Thanks for your very fast response. That's what I saw when casually stepping into libmariadb with the debugger.

            krlmlr Kirill Müller added a comment - Thanks for your very fast response. That's what I saw when casually stepping into libmariadb with the debugger.
            georg Georg Richter added a comment -

            Fixed in 2.3.5 and 3.0.3

            About integrating test framework: Let's discuss it after CONC-300 (travis integration) is closed.

            georg Georg Richter added a comment - Fixed in 2.3.5 and 3.0.3 About integrating test framework: Let's discuss it after CONC-300 (travis integration) is closed.
            krlmlr Kirill Müller added a comment -

            Thanks, Georg. Confirmed that RMariaDB now works unchanged with current master.

            RMariaDB is already tested on Travis, so adding a build matrix entry should be easy once you have your tests there.

            krlmlr Kirill Müller added a comment - Thanks, Georg. Confirmed that RMariaDB now works unchanged with current master. RMariaDB is already tested on Travis, so adding a build matrix entry should be easy once you have your tests there.

            People

              georg Georg Richter
              krlmlr Kirill Müller
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              Dates

                Created:
                Updated:
                Resolved:

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