Skip navigation links
5.1.7 Changes in MySQL 5.0.75 (17 December 2008) »
Section Navigation      [Toggle]

5.1.6. Changes in MySQL 5.0.77 (28 January 2009)

Bugs fixed:

  • Important Change: Security Fix: Additional corrections were made for the symlink-related privilege problem originally addressed in MySQL 5.0.60. The original fix did not correctly handle the data directory path name if it contained symlinked directories in its path, and the check was made only at table-creation time, not at table-opening time later. (Bug#32167, CVE-2008-2079)

    See also Bug#39277.

  • Incompatible Change: There were some problems using DllMain() hook functions on Windows that automatically do global and per-thread initialization for libmysqld.dll:

    • Per-thread initialization: MySQL internally counts the number of active threads, which causes a delay in my_end() if not all threads have exited. But there are threads that can be started either by Windows internally (often in TCP/IP scenarios) or by users. Those threads do not necessarily use libmysql.dll functionality but still contribute to the open-thread count. (One symptom is a five-second delay in times for PHP scripts to finish.)

    • Process-initialization: my_init() calls WSAStartup that itself loads DLLs and can lead to a deadlock in the Windows loader.

    To correct these problems, DLL initialization code now is not invoked from libmysql.dll by default. To obtain the previous behavior (DLL initialization code will be called), set the LIBMYSQL_DLLINIT environment variable to any value. This variable exists only to prevent breakage of existing Windows-only applications that do not call mysql_thread_init() and work okay today. Use of LIBMYSQL_DLLINIT is discouraged and is removed in MySQL 6.0. (Bug#37226, Bug#33031)

  • Incompatible Change: SHOW STATUS took a lot of CPU time for calculating the value of the Innodb_buffer_pool_pages_latched status variable. Now this variable is calculated and included in the output of SHOW STATUS only if the UNIV_DEBUG symbol is defined at MySQL build time. (Bug#36600)

  • Incompatible Change: In connection with view creation, the server created arc directories inside database directories and maintained useless copies of .frm files there. Creation and renaming procedures of those copies as well as creation of arc directories has been discontinued.

    This change does cause a problem when downgrading to older server versions which manifests itself under these circumstances:

    1. Create a view v_orig in MySQL 5.0.72 or higher.

    2. Rename the view to v_new and then back to v_orig.

    3. Downgrade to an older 5.0.x server and run mysql_upgrade.

    4. Try to rename v_orig to v_new again. This operation fails.

    As a workaround to avoid this problem, use either of these approaches:

    • Dump your data using mysqldump before downgrading and reload the dump file after downgrading.

    • Instead of renaming a view after the downgrade, drop it and recreate it.

    The downgrade problem introduced by the fix for this bug has been addressed as Bug#40021. (Bug#17823)