Miscellaneous Functions {aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee} mysql>  SELECT IS_UUID(’6ccd780c-baba-1026-9564-5b8c656024db’); +-------------------------------------------------+ | IS_UUID(’6ccd780c-baba-1026-9564-5b8c656024db’) | +-------------------------------------------------+ | 1 | +-------------------------------------------------+ mysql>  SELECT IS_UUID(’6CCD780C-BABA-1026-9564-5B8C656024DB’); +-------------------------------------------------+ | IS_UUID(’6CCD780C-BABA-1026-9564-5B8C656024DB’) | +-------------------------------------------------+ | 1 | +-------------------------------------------------+ mysql>  SELECT IS_UUID(’6ccd780cbaba102695645b8c656024db’); +---------------------------------------------+ | IS_UUID(’6ccd780cbaba102695645b8c656024db’) | +---------------------------------------------+ | 1 | +---------------------------------------------+ mysql>  SELECT IS_UUID(’{6ccd780c-baba-1026-9564-5b8c656024db}’); +---------------------------------------------------+ | IS_UUID(’{6ccd780c-baba-1026-9564-5b8c656024db}’) | +---------------------------------------------------+ | 1 | +---------------------------------------------------+ mysql>  SELECT IS_UUID(’6ccd780c-baba-1026-9564-5b8c6560’); +---------------------------------------------+ | IS_UUID(’6ccd780c-baba-1026-9564-5b8c6560’) | +---------------------------------------------+ | 0 | +---------------------------------------------+ mysql>  SELECT IS_UUID(RAND()); +-----------------+ | IS_UUID(RAND()) | +-----------------+ | 0 | +-----------------+ 2448 On a multithreaded replica, the function waits until expiry of the limit set by the slave_checkpoint_group  or  slave_checkpoint_period  system variable, when the checkpoint This function is useful for control of source/replica synchronization. It blocks until the replica has read and applied all updates up to the specified position in the source’s binary log. The return value is the number of log events the replica had to wait for to advance to the specified position. The function returns NULL  if the replication SQL thread is not started, the replica’s source information is not initialized, the arguments are incorrect, or an error occurs. It returns  -1  if the timeout has been exceeded. If the replication SQL thread stops while  MASTER_POS_WAIT()  is waiting, the function returns  NULL . If the replica is past the specified position, the function returns immediately. • MASTER_POS_WAIT( log_name , log_pos [, timeout ][, channel ]) For the meanings of fields within the value, see the  UUID()  function description.