• Dmitry Lenev's avatar
    Fix for bug #51105 "MDL deadlock in rqg_mdl_stability test · dcaa1448
    Dmitry Lenev authored
    on Windows".
    
    On platforms where read-write lock implementation does not
    prefer readers by default (Windows, Solaris) server might
    have deadlocked while detecting MDL deadlock.
    
    MDL deadlock detector relies on the fact that read-write
    locks which are used in its implementation prefer readers
    (see new comment for MDL_lock::m_rwlock for details).
    So far MDL code assumed that default implementation of
    read/write locks for the system has this property.
    Indeed, this turned out ot be wrong, for example, for
    Windows or Solaris. Thus MDL deadlock detector might have
    deadlocked on these systems.
    
    This fix simply adds portable implementation of read/write
    lock which prefer readers and changes MDL code to use this
    new type of synchronization primitive.
    
    No test case is added as existing rqg_mdl_stability test can
    serve as one.
    dcaa1448
config.h.cmake 17.5 KB