-- SET GLOBAL log_output = 'TABLE';
-- SET GLOBAL general_log = 'ON';

SELECT * FROM  mysql.general_log  
WHERE command_type ='Query' 
and event_time > '2020-01-03 11:58:20'
ORDER BY event_time DESC
LIMIT 10

-- SET GLOBAL general_log = 'OFF';

Labels: mysql, noteToSelf

It turns out that many variable length data types (and some that are fixed length, like CHAR) are represented internally with the same varlena data structure, which is simply a byte array prefixed with a 32-bit length field.

Labels: mysql

There's still one problem, but I guess I can ignore it.
Setting precision explicitely means [MySQL] uses this precision always.
e.g. even for lower precision numbers.
So, 13.12847910000005 becomes 13.128479100000050 (15 precision) or even 13.1284791000000496 (16 precision).

If one needs to have accurate numbers you better store them as strings. And if you need to display accurate numbers but also calculate in MySQL with the floating point numbers you have to store two values, one float, one string.

Labels: mysql, noteToSelf

UNHEX(REPLACE(uuid, '-', ''))

will convert uuid to 16-byte string
There's no easy way to do a reverse conversion yet. HEX() will do, but
you'll lose dashes.

Labels: mysql, noteToSelf

Real Studio is able to connect to the Community (free) edition of MySQL, but this edition usually requires you to open source software that connects to it (due to its GPL license). 

So that is why they care. They have big plans for a business around MySQL, and they want to make some money from it. MariaDB is their fork of MySQL. Of course, there's nothing wrong with making money. Notice the role of the Open Database Alliance in all this, in case anyone tells you there is no connection. There is.

And in the ultimate irony, Richard Stallman himself joined the fray against... Richard Stallman?

Even Richard Stallman, co-author of the GPL and founder of the free-software movement, and not someone that spends much time worrying about monetization of open-source software, gets this.

As noted in a letter co-drafted with Open Rights Group and Knowledge Ecology International, Stallman notes that Oracle's proposed acquisition of MySQL could hurt its development because the GPL reduces incentives to commercialize the code.

There are many issues here getting mixed up.

First, in fairness to Stallman, when he talks about a "lack of a more flexible license" for MySQL he's really talking about GPL v3 -- or more specifically mixing v2 and v3 code together in a possible future fork. Matt's selective quoting above seem to misrepresent Stallman's position by removing its context.

Second, even under GPL v2, there is *nothing* preventing a "MySQL 2" to "arise, take the code, hire all of the developers, and development of the open-source database would not miss a beat." A new entity under GPL *can* fork MySQL code and do all that. What the new entity *cannot* do is re-license the forked code under a different license -- including GPL v3, or a separate Commercial License under a dual-licensing scheme.

So we finally get into the crux of the issue which Matt curiously omits: dual-licensing of GPL v2 code. We all knew it was "evil". Now we're all acting surprised that it could be "evil". Dual-licensing allows companies to give out crack to babies, and then charge them $$$ once they're hooked... completely against the spirit of GPL.

Now, I'm not a fan of GPL. I've been a long proponent for BSD-style licenses (which Apache derives from). Lots of companies "talk" about relicensing from GPL to Apache... but actions speak louder than words.

Labels: gpl, hats of money, licensing, mysql, open, OSS

Labels: mysql