Marko Mäkelä 4105017a58 MDEV-30357 Performance regression in locking reads from secondary indexes ... lock_sec_rec_some_has_impl(): Remove a harmful condition that caused the performance regression and should not have been added in commit b6e41e3872 in the first place. Locking transactions that have not modified any persistent tables can carry the transaction identifier 0. trx_t::max_inactive_id: A cache for trx_sys_t::find_same_or_older(). The value is not reset on transaction commit so that previous results can be reused for subsequent transactions. The smallest active transaction ID can only increase over time, not decrease. trx_sys_t::find_same_or_older(): Remember the maximum previous id for which rw_trx_hash.iterate() returned false, to avoid redundant iterations. lock_sec_rec_read_check_and_lock(): Add an early return in case we are already holding a covering table lock. lock_rec_convert_impl_to_expl(): Add a template parameter to avoid a redundant run-time check on whether the index is secondary. lock_rec_convert_impl_to_expl_for_trx(): Move some code from lock_rec_convert_impl_to_expl(), to reduce code duplication due to the added template parameter. Reviewed by: Vladislav Lesin Tested by: Matthias Leich		2023-03-16 16:00:45 +02:00
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lock0iter.cc	MDEV-20612: Replace lock_sys.mutex with lock_sys.latch	2021-02-11 14:52:10 +02:00
lock0lock.cc	MDEV-30357 Performance regression in locking reads from secondary indexes	2023-03-16 16:00:45 +02:00
lock0prdt.cc	Merge 10.5 into 10.6	2022-09-20 16:53:20 +03:00