It’s been almost 4.5 years since, during some code refactoring, it was decided (or accidentally changed?) that sql_log_bin should become a GLOBAL variable as well as a SESSION one. Almost 2 years ago, during MySQL 5.5 upgrades at Twitter, I filed MySQL Bug 67433 describing in detail how stupid and dangerous this change was, and asking for a reversal.
Nothing has been changed or reversed, so SET GLOBAL sql_log_bin continues to be allowed. I continue to directly see, and hear about damage caused by incorrect use of SET GLOBAL sql_log_bin. So, let me describe just how stupid and dangerous it really is.
What really happens when you run SET GLOBAL sql_log_bin?
If you have a master-slave replication configuration, your master will have binary logging enabled (log_bin) and be recording each[Read more...]