• Davi Arnaut's avatar
    Bug#49141: Encode function is significantly slower in 5.1 compared to 5.0 · e53ecf2d
    Davi Arnaut authored
    The problem was that the multiple evaluations of a ENCODE or
    DECODE function within a single statement caused the random
    generator to be reinitialized at each evaluation, even though
    the parameters were constants.
    
    The solution is to initialize the random generator only once
    if the password (seed) parameter is constant.
    
    This patch borrows code and ideas from Georgi Kodinov's patch.
    
    mysql-test/r/func_str.result:
      Add test case result.
    mysql-test/r/ps.result:
      Add test case result.
    mysql-test/t/func_str.test:
      Add test case for Bug#49141
    mysql-test/t/ps.test:
      Add test case for Bug#49141
    sql/item_strfunc.cc:
      Move seed generation code to a separate method.
      Seed only once if the password (seed) argument
      is constant.
      Remove duplicated code and use a transform method
      to apply encoding or decoding.
    sql/item_strfunc.h:
      Add parameter to signal whether the PRNG is already seeded.
      Introduce transform method.
      Combine val_str methods.
    sql/sql_crypt.cc:
      Remove method.
    sql/sql_crypt.h:
      Seed is supplied as two long integers.
    e53ecf2d
sql_crypt.cc 1.94 KB