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MDEV-27774 Reduce scalability bottlenecks in mtr_t::commit()

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A prominent bottleneck in mtr_t::commit() is log_sys.mutex between
log_sys.append_prepare() and log_close().

User-visible change: The minimum innodb_log_file_size will be
increased from 1MiB to 4MiB so that some conditions can be
trivially satisfied.

log_sys.latch (log_latch): Replaces log_sys.mutex and
log_sys.flush_order_mutex. Copying mtr_t::m_log to
log_sys.buf is protected by a shared log_sys.latch.
Writes from log_sys.buf to the file system will be protected
by an exclusive log_sys.latch.

log_sys.lsn_lock: Protects the allocation of log buffer
in log_sys.append_prepare().

sspin_lock: A simple spin lock, for log_sys.lsn_lock.

Thanks to Vladislav Vaintroub for suggesting this idea, and for
reviewing these changes.

mariadb-backup: Replace some use of log_sys.mutex with recv_sys.mutex.

buf_pool_t::insert_into_flush_list(): Implement sorting of flush_list
because ordering is otherwise no longer guaranteed. Ordering by LSN
is needed for the proper operation of redo log checkpoints.

log_sys.append_prepare(): Advance log_sys.lsn and log_sys.buf_free by
the length, and return the old values. Also increment write_to_buf,
which was previously done in log_close().

mtr_t::finish_write(): Obtain the buffer pointer from
log_sys.append_prepare().

log_sys.buf_free: Make the field Atomic_relaxed,
to simplify log_flush_margin(). Use only loads and stores
to avoid costly read-modify-write atomic operations.

buf_pool.flush_list_requests: Replaces
export_vars.innodb_buffer_pool_write_requests
and srv_stats.buf_pool_write_requests.
Protected by buf_pool.flush_list_mutex.

buf_pool_t::insert_into_flush_list(): Do not invoke page_cleaner_wakeup().
Let the caller do that after a batch of calls.

recv_recover_page(): Invoke a minimal part of
buf_pool.insert_into_flush_list().

ReleaseBlocks::modified: A number of pages added to buf_pool.flush_list.

ReleaseBlocks::operator(): Merge buf_flush_note_modification() here.

log_t::set_capacity(): Renamed from log_set_capacity().
This commit is contained in:
Marko Mäkelä
2022-02-10 16:37:12 +02:00
parent 8c7c92adf3
commit a635c40648
32 changed files with 487 additions and 512 deletions
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2
mysql-test/suite/perfschema/r/sxlock_func.result
View File

@ -10,6 +10,7 @@ name
wait/synch/rwlock/innodb/dict_operation_lock
wait/synch/rwlock/innodb/fil_space_latch
wait/synch/rwlock/innodb/lock_latch
wait/synch/rwlock/innodb/log_latch
wait/synch/rwlock/innodb/trx_i_s_cache_lock
wait/synch/rwlock/innodb/trx_purge_latch
TRUNCATE TABLE performance_schema.events_waits_history_long;
@ -41,6 +42,7 @@ ORDER BY event_name;
event_name
wait/synch/rwlock/innodb/fil_space_latch
wait/synch/rwlock/innodb/lock_latch
wait/synch/rwlock/innodb/log_latch
SELECT event_name FROM performance_schema.events_waits_history_long
WHERE event_name = 'wait/synch/sxlock/innodb/index_tree_rw_lock'
AND operation IN ('try_shared_lock','shared_lock') LIMIT 1;