It is now possible to undo basic file operations and to redo them. Undo and Redo can be used for 'move', 'rename', 'trash', 'link' and 'create' operations. Per default, a history of the last 10 operations is stored, though the history length is configurable. Whenever an Undo/Redo is triggered, a notification with few details will be shown.
開頭就有先提到重點,在新版 MySQL 裡,幾乎所有的情況比較大的 redo log 有比較好的效能 (平均值):
tl;dr - conclusions specific to my test
A larger redo log improves throughput
A larger redo log helps more with slower storage than with faster storage because page writeback is more of a bottleneck with slower storage and a larger redo log reduces writeback.
A larger redo log can help more when the working set is cached because there are no stalls from storage reads and storage writes are more likely to be a bottleneck.
InnoDB in MySQL 5.7.17 is much faster than 5.6.35 in all cases except IO-bound + fast SSD
The results above show average throughput and that hides a lot of interesting behavior. We expect throughput over time to not suffer from variance -- for both InnoDB and for MyRocks. For many of the results below there is a lot of variance (jitter).