changes of mysql 5.6.20

new option

innodb

replication

#dump thread reconnects from slave; on master, a new dump thread tries to kill zombie dump threads; having acquired the thread’s lock_thd_data, it is about to acquire lock_log.

#application thread executing show binary logs, having acquired lock_log and about to acquire lock_index.

#application thread executing purge binary logs; having acquired lock_index, it is about to acquirelock_thread_count.

#application thread executing show processlist (or select * from information_schema.processlist), having acquired lock_thread_count and about to acquire the zombie dump thread’s lock_thd_data.

this leads to the 4 threads deadlocking in the same order which the threads have been listed here.

server layer/optimizer

ddl

innodb full-text

memcached plugin

partition table

selecting from a table having multiple columns in its primary key and partitioned by list columns(r), where r was the last (rightmost) column listed in the primary key definition, returned an incorrect result.(bug#71095)