Практика Shadowing: MySQL took 21 years to fix this bug - Изучайте разговорный английский с YouTube
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In my 16 years as a software developer,
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In my 16 years as a software developer,
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nothing made me happier than avoiding an annoying bug long enough for someone else to accidentally fix it,
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or for the entire feature to be removed before I ever had to touch that code.
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In fact, after years of hard work and dedication,
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I can proudly say that I have polished this skill to perfection.
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As some of the more experienced among you already know,
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avoiding a ticket without looking like you are avoiding a ticket is an art form.
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You cannot just ignore it,
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because that is amateur work.
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A seasoned senior software developer who earns their keep will occasionally comment something vague,
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like, I'll have to circle back to it when my priorities allow it,
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or this is a tough one,
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but I believe I'm finally close to a solution.
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Then, they let a little more time pass and hope for the best.
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And, hope, as you eventually learn,
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is basically at the core of software development.
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So when I tell you
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that the MySQL team avoided a single bug ticket for 21 years and somehow made it look almost professional,
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understand that I say this with deep, deep respect.
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When a bug is first reported in 2005,
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and you get to fix it in 2026,
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we should all sit down,
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take notes and learn a thing or two about surviving this industry.
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The bug in question is MySQL bug number 11472,
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filed on June 21st, 2005.
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To give you a sense of how long ago that was,
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the iPhone did not exist,
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the most popular browser on Earth was Internet Explorer 6
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and Sam Altman was busy creating a social network instead of convincing the world
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that AI tokens are as important as access to electricity or water.
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We see a future where intelligence is a utility,
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like electricity or water, and people buy it from us.
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Anyway, the reported bug was apparently pretty straightforward.
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Triggers were not firing when a foreign key cascade modified a row.
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For those unfamiliar with relational databases,
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a foreign key is basically a rule that says that this piece of data,
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like some orders, depends on some other piece of data, like a customer.
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Cascades, on the other hand,
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are what happen when the database automatically propagates a change through that relationship.
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So when you delete a customer,
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the database can be told to automatically delete that customer's orders for you.
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Now, there is a whole separate discussion about whether physically deleting records from a database is a bad practice,
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but that is not the topic of this video.
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Just keep in mind that in many cases,
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you are better off keeping the records in the database and using a soft delete instead,
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which simply means marking a row as deleted with a boolean flag.
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Back to the bug, when one of these automated cascade deletes happens,
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my SQL goes and removes the affected child rows for you,
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but it does it quietly.
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So quietly that the triggers attached to those rows have no idea anything happened.
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Triggers, if you have not run into them before,
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are little bits of code that you tell the database to run automatically whenever a specific event happens on a specific table.
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Again, there is an entire discussion on the topic of best practices
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when it comes to triggers and there is an ongoing fight about them in the industry.
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The modern application crowd will tell you triggers are invisible,
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untestable and a debugging nightmare
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and honestly they are not wrong a trigger does not show up in your git dev
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or in code review and a new developer joining your team might be surprised to find out
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that half the logic of your application is happening inside the database fired off by little scripts
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that nobody has looked at for the past 15 years also triggers do not translate
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when you migrate from one database to another because every database has its own slightly different trigger syntax.
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On the other hand, the database crowd,
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mostly old-school DBAs, will tell you
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that triggers are the only thing in your entire stack that catches every change to your data,
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no matter where it came from.
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If you have three different services,
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a cron job, and some random script all writing to the same database,
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only a trigger sees all the changes reliably.
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But enough with the boring theory,
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let's get back to the actual bug report.
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A few days after the initial report,
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the MySQL team says the plan is to fix it in their upcoming 5.1 release.
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Again, take notes, because this is the kind of confidence you guys need to succeed in this career.
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Then, a few days, sorry,
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a few years pass, and in 2007,
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a new comment from the team states that MySQL's own foreign key implementation will eventually fix this,
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but it will still take some time.
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Then, two years later, the confirmation that this bug will not be fixed in 5.1 is posted.
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In 2013, 8 years in,
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a user asks for an update.
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The official reply this time,
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and I want you to appreciate the craftsmanship here,
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says Note that there is major development work needed to fix this issue,
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it will not be a mere bug fix.
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At this point, the bug is starting to become somewhat of a meme because a user replies in the thread,
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the guys over at Oracle probably aren't getting any of these messages because their triggers aren't firing.
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This joke was funny for 13 years straight.
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It's important to note that during this time MySQL changed owners multiple times.
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It started as an open source database built by a small Swedish company.
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It was bought by Sun Microsystems in 2008 for $1 billion,
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which at the time felt like a lot of money.
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Then, in 2010, Oracle bought Sun and inherited MySQL together with the second best programming language in the world.
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And since we are talking about billions of dollars,
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Back to the video, by 2015,
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the comment section enters its second phase when users start showing up on the bug's birthday to leave congratulatory messages like,
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Happy Anniversary, it's 10 years already,
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this defect is going to be attending middle school in the fall and happy 13th birthday they grow up so fast.
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By 2020, we hit a third phase.
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A user writes, this bug is older than me.
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The original reporter, who filed a bug in 2005,
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gets pinged by someone asking if he's still alive
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and he shows up the next day to confirm he is still using MySQL.
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Now, jokes aside, the reason this bug took 21 years to fix is actually pretty interesting
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and it traces its roots in an architectural decision made in the late 90s
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that turned out to be very hard to walk back.
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To explain what happened, I need to tell you a little about how MySQL is built,
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because once you understand the structure,
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the whole bug starts to make sense.
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MySQL is built into layers.
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On top, you have what is called the SQL layer,
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sometimes also called the server layer.
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This is the part of MySQL that takes your queries,
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parses them, plans how to execute them,
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and then asks for the data.
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It is also the part that handles things like triggers,
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views, stored procedures and user permissions.
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Anything that thinks in terms of SQL statements lives here.
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Underneath, you have the storage engine.
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The storage engine is the part that actually reads and writes the bytes on disk.
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This component deals with pages, indexes, logs and transactions.
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My SQL is unusual because its storage engine is pluggable,
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which means you can swap it out,
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but for the past 15 years,
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everyone has been using InnoDB.
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Now, in most databases, foreign keys live in the SQL layer.
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This layer knows about the foreign key,
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this layer enforces it, and when a cascade fires,
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this is the layer that generates the cascade operation as if it were a normal SQL statement.
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As a result, triggers fire normally,
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because triggers are also a SQL layer concept.
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MySQL on the other hand implemented foreign keys inside the InnoDB storage engine.
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The reason is historical and this is also your awesome trivia for the day.
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Early versions of MySQL did not support foreign keys at all.
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The MySQL team famously did not really believe in them
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and you can actually find a page in their version 3 manual titled Reasons not to use foreign keys.
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Their arguments age like milk.
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The first reason they mentioned in the manual is
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that foreign keys make life very complicated because the foreign key definitions must be stored in a database.
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The second reason was that foreign keys are slow and unnecessary and you,
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the developer, will simply remember to insert records in the right order.
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So when they finally added foreign key support,
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they bolted it onto InnoDB,
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because InnoDB was the only engine at the time that supported transactions.
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The SQL layer was never involved,
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so foreign keys became strictly an InnoDB feature.
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So when you run a query such as this one,
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here is what actually happens step by step.
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The SQL layer parses your query,
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it fires the before delete trigger if it exists,
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then it hands the actual delete operation to InnoDB.
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InnoDB then notices, on its own,
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that there is a foreign key with onDelete cascade pointing at the orders table.
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So it walks the orders table,
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finds all the orders that belong to that customer and deletes them itself right there in the storage engine.
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But then, the engine never bubbles back up to the SQL layer to notify it about the additional deletions.
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So the SQL layer, sitting up there with all the triggers,
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is perfectly willing to fire them,
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waiting for someone to tell it that rows on the orders table have changed.
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This was the issue, and as you can see,
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this is what the MySQL team meant in 2013,
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when they wrote that this was not a mere bug fix,
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but major development work.
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The two systems that need to talk to each other are architecturally separated.
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And to finally fix the problem,
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the team did the thing they had been putting off for 21 years.
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They moved foreign keys out of InnoDB and up into the SQL layer.
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If you liked this video,
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you should consider joining our community where I'm posting more dedicated weekly content.
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Please don't forget to smash all the buttons and until next time,
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thank you for watching.
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В этом уроке вы будете работать над улучшением своего разговорного английского, используя технику shadowspeak. Мы рассмотрим интересный и наглядный пример из мира программирования, связанный с исправлением ошибки в MySQL, которая оставалась нерешенной в течение 21 года. Вы научитесь не только понимать специфическую лексику, но и отрабатывать произношение, используя технику shadow speech для лучшего запоминания и понимания структуры языка. Эта практика поможет вам развить уверенность в разговоре и улучшить навыки слушания.
Ключевая лексика и фразы
- bug — ошибка
- foreign key — внешний ключ
- cascade — каскадное удаление
- triggers — триггеры
- database — база данных
- records — записи
- soft delete — мягкое удаление
- silent removal — скрытое удаление
Советы по практике
Для успешной практики shadowspeaks в этом видео рекомендую начать с медленного прослушивания. Внимательно следите за интонацией и ударениями. Постарайтесь сначала просто повторять за говорящим, не обращая внимания на смысл. Это поможет вам сосредоточиться на произношении и ритме речи. Затем, когда вы будете чувствовать себя более уверенно, переходите к более быстрому воспроизведению. Применяйте метод shadow speech — повторяйте фразы сразу же после их произнесения. Это поможет вам встроить фразы в свою активную лексику. Не забывайте делать перерывы для осмысления: иногда лучше сделать паузу и переосмыслить материал, чем пытаться повторить всё сразу. Ваша цель — не только запомнить слова, но и научиться говорить с естественным темпом и интонацией.
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Shadowing — это научно обоснованная техника изучения языка, изначально разработанная для подготовки профессиональных переводчиков и популяризированная полиглотом доктором Александром Аргуэльесом. Метод прост, но эффективен: вы слушаете аудио на английском от носителей языка и немедленно повторяете вслух — как тень, следующая за говорящим с задержкой в 1–2 секунды. В отличие от пассивного прослушивания или грамматических упражнений, Shadowing заставляет мозг и мышцы рта одновременно обрабатывать и воспроизводить реальные речевые паттерны. Исследования показывают, что это значительно улучшает точность произношения, интонацию, ритм, связную речь, понимание на слух и беглость речи — что делает его одним из самых эффективных методов для подготовки к IELTS Speaking и реального общения на английском.
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