Fix bug 1519094 (MySQL hangs randomly) #252
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The issue is incorrect upstream fix for https://bugs.mysql.com/bug.php?id=76135. On x86, it replaced full memory barriers at mutex lock/unlock with acquire/release ones. This broke synchronisation between mutex lock_word and waiters flag, resulting in missed waiting thread wakeups. These, in combination with error monitor thread trying to acquire the mutex with a missed wakeup, result in a server hang. Fix by restoring previous behavior of full memory barriers on x86_64.
laurynas-biveinis
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Fix bug 1519094 (MySQL hangs randomly)
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The issue is incorrect upstream fix for
https://bugs.mysql.com/bug.php?id=76135. On x86, it replaced full
memory barriers at mutex lock/unlock with acquire/release ones. This
broke synchronisation between mutex lock_word and waiters flag,
resulting in missed waiting thread wakeups. These, in combination with
error monitor thread trying to acquire the mutex with a missed wakeup,
result in a server hang.
Fix by restoring previous behavior of full memory barriers on x86_64.
Not an upmerge because of 5.5.46 merge dependency.
http://jenkins.percona.com/job/percona-server-5.6-param/1036/