• Konstantin Osipov's avatar
    A fix and a test case for · 409160e4
    Konstantin Osipov authored
    Bug#41756 "Strange error messages about locks from InnoDB".
          
    In JT_EQ_REF (join_read_key()) access method, 
    don't try to unlock rows in the handler, unless certain that 
    a) they were locked
    b) they are not used.
    
    Unlocking of rows is done by the logic of the nested join loop,
    and is unaware of the possible caching that the access method may
    have. This could lead to double unlocking, when a row
    was unlocked first after reading into the cache, and then 
    when taken from cache, as well as to unlocking of rows which
    were actually used (but taken from cache).
          
    Delegate part of the unlocking logic to the access method,
    and in JT_EQ_REF count how many times a record was actually 
    used in the join. Unlock it only if it's usage count is 0.
    
    Implemented review comments.
    409160e4
item_subselect.cc 70.9 KB