Consider the scenario that you execute a query. You expect it to be fast - typically subsecond - but now it take not return until after 50 seconds (innodb_lock_wait_timeout seconds) and then it returns with an error:

mysql> UPDATE world.City SET Population = Population + 999 WHERE ID = 130;
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

You continue to investigate the issue using the sys.innodb_lock_waits view or the underlying Information Schema tables (INNODB_TRX, INNODB_LOCKS and INNODB_LOCK_WAITS).

Note: …

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons.

For one, most of you might have noticed that profiling was marked as deprecated in MySQL 5.6.7. So it is expected that you invest into learning more about Performance Schema (and Mark’s sys schema!).

Second, there are lots of virtual environments and appliances out there running Community Edition MySQL where Performance Schema can be a useful tool for analyzing performance. Thus, expect to see more articles about using PERFORMANCE_SCHEMA and SYS_SCHEMA from us!

Third, we have more and more junior readers who might benefit from light reads such as this.

The new defaults that I wanted to highlight are mentioned in the …