AcquireShared acquires Synchronize status, and multiple threads can obtain Synchronize status at the same time. Does this mean that there are multiple head nodes?

when I was reading, in the queue synchronizer, it is said that only the head node can have the Synchronize status. In the shared access Synchronize status, acquireShared allows multiple threads to obtain the Synchronize status when obtaining the Synchronize status. Is the head node one or some other way?

Feb.27,2021

I have found the answer. Through the setHeadAndPropagate method, wake up the remaining threads

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1ea6c26-47bc6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1ea6c26-47bc6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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