We noticed that the 5.6.6-m9 code that handles the update rows log
event on a slave looks as if it no longer fetches the row as MySQL 5.5
does (5.5 calls find_row to fetch the row) before calling the storage
engine update_row method. Here are some questions:
1. Is it in fact the case that 5.6 does not read the row when
executing update log events on the slave? The log event has the
before and after update versions of the row, so reading the row seems
2. Why was this change made?
3. Can the same change be applied to MySQL 5.5? If so, are there any
addition changed needed?