• Kristofer Pettersson's avatar
    Bug#38551 query cache can still consume [very little] cpu time even when it is off. · a4802406
    Kristofer Pettersson authored
          
    When the query cache is disabled, the server shouldn't attempt to take the 
    query cache mutex.
                                 
    By using the command line option --query_cache_type=0, the user can disable
       
    (backport from mysql-pe)
    
    
    mysql-test/t/query_cache_disabled-master.opt:
      * added test case for bug38551
    mysql-test/t/query_cache_disabled.test:
      * added test case for bug38551
    sql/set_var.cc:
      * Added before-trigger to verify that query_cache_type wasn't turned off or on during
      runtime.
    sql/set_var.h:
      * Changed order on how the enumeration is processed. By first projecting the
      character representation of the variable to a temporary integer we can have
      one function instead of two to check if the value is valid.
    sql/share/errmsg-utf8.txt:
      * Added error message for query cache disabled state
    sql/sql_cache.cc:
      * If the query cache is disabled at start up, shorten the execution path and avoid
      grabbing the query cache mutex each time the invalidate interface methods are called.
    sql/sql_cache.h:
      * Added new methods to set the query cache into a disabled state.
    a4802406
errmsg-utf8.txt 442 KB