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Well, the things it would have been nice for MySQL to have done would have been not implementing it this way in the first place (yes, that's probably not Oracle

Well, the things it would have been nice for MySQL to have done would have been not implementing it this way in the first place (yes, that's probably not Oracle's fault), and moving utf8 to utf8mb4 a bit more quickly. (good to know that's finally happening). Also, I gotta say, now I have to look into this strict mode and what else it breaks, when in this particular case a "don't silently truncate strings" flag would be preferable and probably lower impact, since "strict" vs "security flaw mitigation" is not quite the same thing (does such a more granular flag exist?). ... unless that's all the strict mode does. Hm, and since you brought this up elsewhere. Is this "strict by default" in MariaDB - which is what most (linux) people are (probably) thinking of.

ars 5y ago
> and moving utf8 to utf8mb4 a bit more quickly. (good to know that's finally happening). That happened in 2010 - I'm not sure 12 years counts as "finally happening", or just how much quicker you would like than 12 years ago? Other than a time machine, I'm not sure what else you would like them to do.
- butlerm 5y ago
  They should have made "utf8" have UTF-8 semantics by default as soon as the defect was discovered, not twenty plus years later.
  - ars 5y ago
    They couldn't. The storage size is different internally. The article covers this in the section in migrating from utf8 to utf8mb4. Do you actually use MySQL or are you just complaining from a theoretical POV?
    - butlerm 5y ago
      Pretty sure the name "utf8" isn't metaphysically wired to a defective physical representation. All they have to do is wait until the next minor release, add a compatibility name, make the generic name refer to a non-defective representation, and update the documentation and release notes accordingly. If they were really conservative, they could wait until the next major release to repoint the name like that. Haven't there been four major releases since 2003?
      - evanelias 5y ago
        This would be problematic for existing applications. Even if you leave existing binary data as-is (in existing tables utf8 becomes utf8mb3), changing the meaning of "utf8" in only new tables is still very problematic. Think about logical dumps, e.g. CREATE TABLE statements which use the "utf8" alias. For example, any self-host application which runs a .sql file in its install process. Or spinning up a dev environment for a new hire. Basically, anything that contains a CREATE TABLE with the utf8 alias now has a landmine: In older versions of MySQL, InnoDB indexes were limited to 767 bytes. Meanwhile, VARCHAR(N) can store N characters. So with utf8mb3, that's a max of 3N bytes worst-case; but with utf8mb4 ("proper" utf8), it's now 4N. This meant that VARCHAR(255) CHARACTER SET utf8mb4 could not be indexed (in its entirety) in these older versions; the CREATE TABLE would fail if you try. When you have a massive installed base of users, and those users have lots of dumps / install scripts containing "VARCHAR(255) CHARACTER SET utf8", you simply cannot change the meaning of "utf8" in a minor release. I fully agree that MySQL could have made this transition faster/earlier than they did, but I disagree that it could be done trivially or terribly quickly.
        butlerm 5y ago
        Advertising the ability to store UTF-8 characters when you can do no such thing is a serious problem. Obviously you have to do whatever it takes to fix it, including fixing a deficient indexing implementation if necessary. I believe the limitation you mention was fixed in MySQL 5.7, which would have been a reasonable opportunity to make "utf8" live up to its name.
        evanelias 5y ago
        Keep in mind that prior to 2010, MySQL and InnoDB were owned by different companies. Unilaterally deciding to increase the InnoDB index size limitation to permit utf8mb4 varchar(255) was not physically possible for the MySQL team prior to that point. Anyway, I fully agree that the utf8 alias swap should have been done in MySQL 5.7, or perhaps even 5.6. I'm just disagreeing with your assertions that this would have been a trivial change. Nor do I think it should have been a "stop the world" high-priority change prior to emoji existing in unicode (~late 2010). Non-BMP characters were very rare before that point. Hard to justify a business need for a complex migration just to store archaic hieroglyphs. For another point of comparison, MS SQL Server only added support for non-BMP characters in 2012, and only added support for utf8 encoding in 2019!
- capitainenemo 5y ago
  I mean the announced plan to make the "utf8" default be utf8mb4 instead of utf8mb3. See https://news.ycombinator.com/item?id=29910023 https://news.ycombinator.com/item?id=29910023
evanelias 5y ago
> moving utf8 to utf8mb4 a bit more quickly I definitely agree! > now I have to look into this strict mode and what else it breaks It's a mode to ensure nothing happens silently: illegal data type conversions, attempting to insert invalid values for the data type (too large, too long, invalid characters, etc), attempting to do an INSERT which doesn't specify some columns that lack defaults, etc. With strict mode enabled, all of these things throw hard errors, like in most other relational databases. Generally, it covers the entire class of things that are typically the most common complaints about MySQL on HN. Interesting wording re: "breaks" -- for practical purposes this is a real concern for existing applications, which may be doing bad things which previously didn't throw errors with strict mode off. Do you want your DB to suddenly fail loudly for these things (strict mode), or do you want your existing application to continue working in these cases? Can't have it both ways. > Is this "strict by default" in MariaDB - which is what most (linux) people are (probably) thinking of. MariaDB made it default in 10.2, ~5 years ago. I don't agree that most Linux people conflate MySQL and MariaDB though. At large US tech companies that use MySQL, they're almost all literally using Oracle MySQL, or a patch-set like Percona Server which directly tracks MySQL, or an internal patch-set that does the same. In recent years, MySQL and MariaDB have diverged a bit on feature set and focus; each has some interesting features that the other lacks. They are not drop-in replacements for each other.
- capitainenemo 5y ago
  So... while I'm broadly in agreement with you, and a huge fan of strict typing, I will note people use languages like Javascript and usually are ok with things like string to integer coercion. It seems to be that there's a world of difference between "silently truncate string" and "type coercion" even if I readily agree both are sources of security vulnerabilities. Thanks for the replies though, even though I clearly annoyed at least 2 people due to the downvotes.
sinner 5y ago
I enabled strict sql mode in MariaDB for an website just last year, after noticing the database was silently corrupting data. What made the transition much less painful was noticing that when strict sql mode is disabled, MariaDB produces a warning for the queries that corrupted the data, but you must run SHOW WARNINGS; to see the warnings after running such a query. Knowing that, I made the website run SHOW WARNINGS; after every database query and logging if a warning occurred. This allowed me to deal with the most of the warnings before they were promoted to errors by enabling strict sql mode.

ars 5y ago

> and moving utf8 to utf8mb4 a bit more quickly. (good to know that's finally happening). That happened in 2010 - I'm not sure 12 years counts as "finally happening", or just how much quicker you would like than 12 years ago? Other than a time machine, I'm not sure what else you would like them to do.

butlerm 5y ago
They should have made "utf8" have UTF-8 semantics by default as soon as the defect was discovered, not twenty plus years later.
- ars 5y ago
  They couldn't. The storage size is different internally. The article covers this in the section in migrating from utf8 to utf8mb4. Do you actually use MySQL or are you just complaining from a theoretical POV?
  - butlerm 5y ago
    Pretty sure the name "utf8" isn't metaphysically wired to a defective physical representation. All they have to do is wait until the next minor release, add a compatibility name, make the generic name refer to a non-defective representation, and update the documentation and release notes accordingly. If they were really conservative, they could wait until the next major release to repoint the name like that. Haven't there been four major releases since 2003?
    - evanelias 5y ago
      This would be problematic for existing applications. Even if you leave existing binary data as-is (in existing tables utf8 becomes utf8mb3), changing the meaning of "utf8" in only new tables is still very problematic. Think about logical dumps, e.g. CREATE TABLE statements which use the "utf8" alias. For example, any self-host application which runs a .sql file in its install process. Or spinning up a dev environment for a new hire. Basically, anything that contains a CREATE TABLE with the utf8 alias now has a landmine: In older versions of MySQL, InnoDB indexes were limited to 767 bytes. Meanwhile, VARCHAR(N) can store N characters. So with utf8mb3, that's a max of 3N bytes worst-case; but with utf8mb4 ("proper" utf8), it's now 4N. This meant that VARCHAR(255) CHARACTER SET utf8mb4 could not be indexed (in its entirety) in these older versions; the CREATE TABLE would fail if you try. When you have a massive installed base of users, and those users have lots of dumps / install scripts containing "VARCHAR(255) CHARACTER SET utf8", you simply cannot change the meaning of "utf8" in a minor release. I fully agree that MySQL could have made this transition faster/earlier than they did, but I disagree that it could be done trivially or terribly quickly.
      - butlerm 5y ago
        Advertising the ability to store UTF-8 characters when you can do no such thing is a serious problem. Obviously you have to do whatever it takes to fix it, including fixing a deficient indexing implementation if necessary. I believe the limitation you mention was fixed in MySQL 5.7, which would have been a reasonable opportunity to make "utf8" live up to its name.
        evanelias 5y ago
        Keep in mind that prior to 2010, MySQL and InnoDB were owned by different companies. Unilaterally deciding to increase the InnoDB index size limitation to permit utf8mb4 varchar(255) was not physically possible for the MySQL team prior to that point. Anyway, I fully agree that the utf8 alias swap should have been done in MySQL 5.7, or perhaps even 5.6. I'm just disagreeing with your assertions that this would have been a trivial change. Nor do I think it should have been a "stop the world" high-priority change prior to emoji existing in unicode (~late 2010). Non-BMP characters were very rare before that point. Hard to justify a business need for a complex migration just to store archaic hieroglyphs. For another point of comparison, MS SQL Server only added support for non-BMP characters in 2012, and only added support for utf8 encoding in 2019!
capitainenemo 5y ago
I mean the announced plan to make the "utf8" default be utf8mb4 instead of utf8mb3. See https://news.ycombinator.com/item?id=29910023 https://news.ycombinator.com/item?id=29910023

evanelias 5y ago

> moving utf8 to utf8mb4 a bit more quickly I definitely agree! > now I have to look into this strict mode and what else it breaks It's a mode to ensure nothing happens silently: illegal data type conversions, attempting to insert invalid values for the data type (too large, too long, invalid characters, etc), attempting to do an INSERT which doesn't specify some columns that lack defaults, etc. With strict mode enabled, all of these things throw hard errors, like in most other relational databases. Generally, it covers the entire class of things that are typically the most common complaints about MySQL on HN. Interesting wording re: "breaks" -- for practical purposes this is a real concern for existing applications, which may be doing bad things which previously didn't throw errors with strict mode off. Do you want your DB to suddenly fail loudly for these things (strict mode), or do you want your existing application to continue working in these cases? Can't have it both ways. > Is this "strict by default" in MariaDB - which is what most (linux) people are (probably) thinking of. MariaDB made it default in 10.2, ~5 years ago. I don't agree that most Linux people conflate MySQL and MariaDB though. At large US tech companies that use MySQL, they're almost all literally using Oracle MySQL, or a patch-set like Percona Server which directly tracks MySQL, or an internal patch-set that does the same. In recent years, MySQL and MariaDB have diverged a bit on feature set and focus; each has some interesting features that the other lacks. They are not drop-in replacements for each other.

capitainenemo 5y ago
So... while I'm broadly in agreement with you, and a huge fan of strict typing, I will note people use languages like Javascript and usually are ok with things like string to integer coercion. It seems to be that there's a world of difference between "silently truncate string" and "type coercion" even if I readily agree both are sources of security vulnerabilities. Thanks for the replies though, even though I clearly annoyed at least 2 people due to the downvotes.

sinner 5y ago

I enabled strict sql mode in MariaDB for an website just last year, after noticing the database was silently corrupting data. What made the transition much less painful was noticing that when strict sql mode is disabled, MariaDB produces a warning for the queries that corrupted the data, but you must run SHOW WARNINGS; to see the warnings after running such a query. Knowing that, I made the website run SHOW WARNINGS; after every database query and logging if a warning occurred. This allowed me to deal with the most of the warnings before they were promoted to errors by enabling strict sql mode.