As of July 1 all Canadian MySQLers are employees of Sun Microsystems. I was expecting that we would be the rear guard, I was going to greet the great day singing “a broken man on an Edmonton pier / the last of Monty’s engineers” (with thanks to the writer of “Barrett’s privateers”), or perhaps “And I, the last, go forth companionless … Among new men, strange faces, other minds.” (with thanks to Mr Tennyson). But as things turned out, the Ukrainians and the French were delayed. So Trudy Pelzer and I were the last Canadian engineers to come on board, but not quite last of all.

And it’s been wonderful. A free lunch, a tour of Sun’s Edmonton office, a SafeWord security doohickey, a carrying case, and an alternative address = peter.gulutzan@sun.com. More seriously, I’ve …

MySQL’s TRUNCATE statement will evolve over the next few years, as we fix bugs or strange behaviours, and as we try to make storage engines more consistent with each other. Equally interesting are the aspects that will remain the same, as we confirm that our behaviour conforms to standard requirements.

Define TRUNCATE

TRUNCATE T has two definitions:
(1) it means “delete all rows in T”, as the MySQL Reference Manual says in section “TRUNCATE Syntax”. (2) it means “drop T, then create it again”, as the Reference Manual says later on. The better definition is (2). I have proofs.

Proof #1: The required privilege for TRUNCATE is DROP.

Proof #2: TRUNCATE does not cause activation of DELETE triggers. For example:
CREATE TABLE t (s1 INT);
CREATE TRIGGER t_ad AFTER DELETE ON t
FOR …

I can find most of MySQL’s “timeout” variables with a SHOW statement:

mysql> show variables like '%timeout%';+----------------------------+-------+

| Variable_name              | Value |

+----------------------------+-------+

| connect_timeout            | 10    |

| delayed_insert_timeout     | 300   |

| falcon_lock_wait_timeout   | 50    |

| innodb_lock_wait_timeout   | 50    |

| ...................................|

| interactive_timeout        | 28800 |

| net_read_timeout           | 30    |

| net_write_timeout          | 60    |

| slave_net_timeout          | 3600  |

| table_lock_wait_timeout    | 50    |

| wait_timeout               | 28800 |

+----------------------------+-------+

11 rows in set (0.01 sec)

The straightforward list conceals several anomalies and buried controversies.

* Should we allow non-integer values like 0.55 seconds, or perhaps make all values milliseconds rather than seconds, in order to …

Occasionally I hear the worry that MySQL might plan a feature that’s “half baked”. The term’s users include some of the world’s top MySQL experts so I’ll avoid a technical argument.

“In future we should not release a version with half-baked features and call it enterprise-ready.”
– Konstantin Osipov
http://www.xaprb.com/blog/2007/08/12/what-would-make-me-buy-mysql-enterprise/

“will Falcon be pushed hard as Innodb replacement even if it is half baked?”
– Peter Zaitsev
http://www.mysqlperformanceblog.com/page/2/?s=falcon&search_posts=true

As for me, though, I believe in features that others call “half baked”. I just don’t use the term much myself because it seems to convey a wistful regret. While “we’re halfway there” would generally be taken as a report of good progress.

The analogy seems to be with a cake: if you take a cake out of the oven and let …