MySQL for Mac8.0.26

Bugs fixed:

• Incompatible Change: Within trigger bodies, INSERT or UPDATE statements containing a SET clause that used OLD or NEW values as assignment targets could raise an assertion or lead to a server exit. Such assignments are no longer permitted.
• Performance: Internal functions used to copy values between columns have been improved such that computations not necessary when the values are of similar types are no longer performed. Queries using temporary tables should be noticeably faster with this enhancement. Our internal testing has shown such queries being executed up to 11% faster than previously; as always, your results may differ from these depending on environment, configuration, and other factors.
• InnoDB: To reduce the number of unnecessary warning messages in the error log, instances of the fil_space_acquire() function in the InnoDB sources were replaced by the fil_space_acquire_silent() function where possible.
• InnoDB: The TRX_FORCE_ROLLBACK_ASYNC flag in the InnoDB sources, which indicates whether a transaction was rolled back asynchronously or by the owning thread, was found to be redundant and has been removed.
• InnoDB: Use of the ut_delete symbol instead of the UT_DELETE macro in the InnoDB sources caused a failure in builds that disable Performance Schema memory tracing (-DDISABLE_PSI_MEMORY=ON).
• InnoDB: Dictionary system mutex_enter and mutex_exit calls in the InnoDB sources were renamed to dict_sys_mutex_enter() and dict_sys_mutex_exit(), respectively.
• InnoDB: Legacy UNIV_INLINE and UNIV_MATERIALIZE artifacts were removed from InnoDB sources. UNIV_HOTBACKUP was added to method declarations in some header files.
• InnoDB: The lock_sys sharded rw_lock index used random index values generated by the ut_rnd_interval() function, which was not optimal for low-concurrency workloads.
• InnoDB: A string value setting for the innodb_redo_log_encrypt variable was not handled properly.
• InnoDB: Read-write transaction set (trx_sys->rw_trx_set) shards, each with a dedicated mutex, were introduced to alleviate transaction system mutex (trx_sys->mutex) contention caused by transaction set insertions and removals. Related enhancements include moving transaction set modifiers to less critical locations, eliminating heap allocation inside of the TrxUndoRsegs constructor, converting transaction state (trx->state) and transaction start time (trx->start_time) fields to std::atomic fields, and new assertion code to validate threads that operate on transactions.
• InnoDB: Record buffer logic for the InnoDB memcached GET command was revised.
• InnoDB: The ut_list base member in the InnoDB sources now locates list nodes using the element portion of the list type rather than storing a member pointer in the base node of a list at runtime, which waisted resources. The patch also includes other ut_list related code improvements.
• InnoDB: A deadlock between a user thread and purge thread involving a undo log page and rollback segment page occurred after an undo tablespace truncate operation was initiated. The deadlock caused a long semaphore wait and an eventual failure.
• InnoDB: Type-safe enhancements for PSI_memory_key identifiers were introduced. PSI_memory_key identifiers are used by Performance Schema for instrumentation of memory operations. With this enhancement, ut::aligned_name library functions are able to report type errors at compile time.
• InnoDB: The buf_get_LRU_mutex() function was optimized to avoid acquiring the LRU mutex unnecessarily when flushing from the flush list.

Full changelog available here.