Perhaps it's due to me being in the PostgreSQL camp, but what happened to MariaDB? I was convinced that's where MySQL developers went and that's where development proceeded, while MySQL was just half dead, because Oracle did not care about it.
That was the expectation but the Oracle camp surprised everyone by actually giving it some attention, and meanwhile MariaDB's promise of being a "100% compatible drop-in replacement" came with more and more caveats with each release (as is to be entirely expected with any fork).
When you consider the network effect of all the stacks already heavily invested in MySQL, all Oracle really needed to do was put in a modicum of effort to MySQL to stave off the MariaDB migrations (and from my understanding they've put in quite a bit more than a modicum).
Lastly, Postgres is an interesting player. Migrating from MySQL to Postgres might be a scarier prospect than to MariaDB, but since the Oracle acquisition a lot of MySQL-veterans were looking for something non-MySQL for new projects and in that I get the sense Postgres beat out MariaDB.
I carried out a (quite ill-advised in retrospect) migration from MySQL to Postgres on a mature codebase with absolutely no automated test coverage and it went pretty smoothly. We had some bumpy performance directly after the production migration but we were able to reach parity after about two months of observing and adding targeted indices.
I absolutely adore Postgres's tweaks to the SQL language, that dialect is amazing and has served us extremely well. And, since we passed pg10 a while back, the performance tuning you can do on it is pretty amazing.
> I absolutely adore Postgres's tweaks to the SQL language
Do you mean additions to the SQL standard, or bits of the standard that MySQL doesn't implement, or something else?
The reason i ask is that i also enjoy writing SQL for PostgreSQL, but as far as i know, i am sticking to standard SQL. Perhaps there are things i'm missing, or things i like which i haven't realised are nonstandard!
There is definitely stuff that is non-standard, like the casting with :: in addition to CAST AS.
But it's true that PSQL sticks very closely to the standard or only adds on top of it, while MySQL is very uncomformant.
Funnily enough, I actually first used Postgres over MySQL a long time ago when I moved from PHP to NodeJS, and was annoyed that MySQL uses backticks for identifiers while PSQL uses SQL standard double quotes, because in JS multi-line strings (for SQL queries) are also use backticks and I was annoyed by escaping. Sometimes it's the little things...
It is practically essential for any RDBMS to provide non-standard statements and features. For example, even CREATE INDEX isn't in the SQL standard, since the SQL standard deliberately avoids talking about what it considers to be implementation details. This is probably a good goal in many ways. But what counts as an implementation detail is open to interpretation.
You could say the same thing about the isolation levels. They are supposed to be platonic ideals, free from any implementation baggage. But the reality is that you can tell that the people that originally defined how they work were mostly (perhaps entirely) thinking about old school two-phase locking.
I'm not a critic of the standard -- it's imperfections (which are arguably contradictions) reflect real world differences that are hard or impossible to resolve. Just pointing out that this is how it is.
Oh, it's totally fair to criticize the standard. Those clowns lock their deliberation and standard definitions behind huge paywalls.
The best way to learn the SQL standard is to read the Postgres docs since they clearly call out non-compliances - there is no other easy to access and clear explanation of the SQL standard.
Alphabetical makes it so two databases with the same triggers have the same behavior. FIFO breaks that, because now it depends on trigger construction order (eg when dump/restoring) and is totally invisible to the user.
Additionally, modifying a trigger by drop/creating it would change behavior, unless you also drop/create every trigger (in the original order)
Easiest I can imagine is a user-facing id that gets incremented by trigger (e.g. select max(col)+1 — autoincrement/serial doesn’t guarantee contiguity, or even reasonable increments…).
And then any second trigger that relies on that value
Not only what @setr answered but consider also that by having a consistent ruling you can actually design or alter the order of triggers just by naming them according to a specific scheme.
It just makes easier to understand what happens when triggers are invoked, without having to actually force specific cases by direct experimentation.
I did not even know that the standard prescribed a FIFO order, looks like a pretty bad idea to me, actually.
Why was this down-voted? It is a good question. I thought exactly the same myself. And the reply from @setr is helpful. (Hat tip) I never thought about the impact of dump/restore!
I absolutely love Postgres' JSON and array support. Its saved me from needing a document database in a few cases, which drastically simplified the overall deployment (one DB instead of two, or trying to represent relational stuff in a document DB). I really like JSON for stuff that is user defined, that I don't need to query into, but postgres' support means I still can should I ever need to. Which has happened once or twice for debugging.
100%. I've dealt with many small-to-medium sized projects where the usual approach would have been some form of EAV mess.
Just using a BSON column for such attributes hits the Pareto 80/20 sweet spot, _and_ I can query against them much more easily than in an EAV schema (far fewer joins).
They're great for when the schema is mostly normalized, but there's just a little bit of denormalized stuff that doesn't warrant completely architecting the schema around it.
Yes, Postgres' jsonb and array support lets you not only query into these fields, but also, like you say, index into them too. Its really the best of both worlds: you get a great solid relational database, but if you need document database features, you don't really lose out on anything by using json, except that the queries are a bit more ugly. I'm super happy with postgres these days, its rock solid and full of fantastic features.
It would be horribly painful to stick to _just_ SQL/JSON for manipulations, and I have absolutely zero idea what the coverage is in other platforms, but portability isn't completely off the table like it used to be
MySQL does not conform to the standard in a number of ways. On the one hand, thankfully you can turn on ANSI MODE. On the other hand if you're using MySQL you've probably got a bunch of devs used to their non-ANSI SQL and turning on ANSI MODE may break stuff they do.
Personally, back before JSON became a standard thing - I made heavy use of HSTORE to clean up some insanely cludgey string packing BS we'd been doing - leveraging recursive CTEs using the UNION definition allowed us to move a fixed tier system into a self-referential one that saved us a lot of headaches as well.
Other folks have mentioned :: instead of CAST AS (which is really nice when you need to write it a bunch of times) but it's mostly the diverse built-in function set and constraint support that keeps me an enthusiastic Postgres supporter.
I assume they mean non-standard additions in PostgreSQL. A lot of the very handy pg functions are non-standard, as well as the rich text matching capabilities, many data types, and even the RETURNING clause, I believe.
Sadly for me when I tried to make a PoC of Postgres for our eCommerce platform I found that we had violated our constraints and lost data.
That was the day I went from MySQL agnostic to MySQL hating.
It largely doesn’t matter that the defaults could be configured to be more strict. We live in a world where people are trying to avoid hiring sysadmin and that database was set up by a developer. It should not have been a default.
> It largely doesn’t matter that the defaults could be configured to be more strict. We live in a world where people are trying to avoid hiring sysadmin and that database was set up by a developer. It should not have been a default.
Everyone agrees with this. That's why they changed the default nearly 6 years ago.
Yes, the old default was terrible. But there's no way to change the past, so why complain about it for years and years?
All versions with this bad default have hit end-of-life, what more can be done?
I am very much an example of one of those previously MySQL devs that now uses Postgres for new projects, though I've never done a migration between the two.
I had an app with a fairly complex and large set of tables and data and migrated it from mySQL to pg with very little trouble. It was a few years back, but from what I recall a re-wrote a few queries in my data layer and that’s about it. Much easier than it was to setup nginx to take over some Apache duties.
It doesn't sound too bad. The incompabilities seem to be mostly stuff like not being able to generally use replication from MySQL to MariaDB or vice versa. But I would guess that's not a very common case anyway: most users are either developers that want their software to work with both MariaDB and MySQL (which can be achieved by sticking to the very large intersection of supported features), or they are users that want to switch from MySQL to MariaDB (which seems well-supported). Running a mix of MariaDB and MySQL servers and expecting to be able to replicate between them seems like a particularly uncommon setup (though maybe it's useful during a migration).
The issues I encountered while using MariaDB in place of MySQL were subtle -- most things worked as expected, which makes the issues so much more unexpected. But at the end of the day, the same migrations produced a different schema.
Arguably MariaDB made the correct decision to fix some MySQL 5.7 bugs that we were unwittingly relying upon, but the different behavior caused issues for us all the same.
Rather than worry about MySQL vs MariaDB and whether the one I need is packaged and available for my distro/OS of choice, I reach for Postgres on new projects.
I think this is a key difference - where MariaDB continues to evolve MySQL 5.6/5.7 codebase Oracle chose the "big leap" with MySQL 8 - introducing data dictionary and many other internal architecture changes. This is one of the reasons migration to MySQL 8 can be more painful than releases before it but for good reason
> meanwhile MariaDB's promise of being a "100% compatible drop-in replacement" came with more and more caveats with each release
Anecdata: I've been using mariadb as a drop in mysql replacement for over 5 years in production, and it's been working seamlessly.
I'm no DB expert, and perhaps my use case isn't complex enough or written in a highly mysql dependent way - but I felt like someone should chime in since there's not much positivity toward mariadb in this thread so far. I'd be interested to hear from some other people with actual mariadb experience.
We migrated a high-traffic, complex site with a huge amount of data to MariaDB about 5 years ago as well, and it's been solid so far. We use Galera as well, which has performed and scaled really admirably.
I think it's still pretty good. I ran into some issues with json support some years ago, but querying json may be an edge case (as opposed to storing text & creating your own indices)
Anyone on the in-crowd who can share a bit about Oracle's motivations here?
I recall a Bryan Cantrill talk about how Oracle is this completely amoral machine that just wants to make money, and how that drives their every decision [0]. Is this no longer the case? Or is it, and if so, how does improving MySQL and giving it away for free making Oracle money? Or was it always hyperbole and Oracle is improving MySQL because they want to be nice?
Oracle paid a lot of money to buy Sun, and basically ended up with two products- selling support for Java and MySQL. Letting MySQL rot would have been pretty bad for their pocket book (especially as others have noted that postgres has been cutting into their market heavily).
In Bryan's defense, the lawnmower rant is pretty true- they are a simple company. They focus heavily on making money and abandoning things they aren't in a good position to do so from.
Selling per-cpu-core licenses and support contracts, great! Experimenting on or converting small projects into new markets? Not great. Fleshing out OpenSolaris into a product that could rival linux? Dead end.
Maybe it could have worked out, but the lawnmower didn't care about a product that had too few users to make money from. OTOH, even Facebook uses MySQL... All they need to do is invest enough to maintain market share to get support contracts.
> Experimenting on or converting small projects into new markets?
Bringing MaximeVM out of research labs into the market as GraalVM.
First RDMS to support Perl and Java as stored procedures.
Join venture with Sun for Network Computer thin clients.
> Fleshing out OpenSolaris into a product that could rival linux?
Every OpenSolaris sales is one sale less from Unbreakable Linux, so in a day and age where UNIX === Linux, a company like Oracle has chosen what makes more sense monetarly.
I doubt that IBM is getting lots of new AIX customers.
And in the end, except for a timid offer from IBM, no one cared to rescue Sun.
I don't think that FB were in a position back then. I was very surprised at the time that Google didn't buy them. Microsoft would never had gotten it past the regulators.
I guess I'm cynical, but to me looks like Oracle renewed interest in MySQL after PostgreSQL gained momentum. MySQL is not really a competitor to Oracle but PostgreSQL overlaps with both of them.
Oracle, compared to their image is quite technically adept — they did a splendid job with OpenJDK and they have plenty of long-term R&D projects like GraalVM.
Yeah so, all of that seemed to happen after that Cantrill talk. How did Oracle suddenly turn from a pure license contract squeezing company into a tech leader again? I mean, they had to hire great engineering talent to do all this. And convince them to work for Oracle. What's the narrative I'm missing?
I'm not familiar with the internal stucture of Oracle, just tired of the imo unfair bashing of them (at least compared to all other companies).
But I guess they must have had at least sane management that tried to keep the existing mindshare of acquired projects (as far as I know many people went from Sun to Oracle directly for example), as well as finding new talent. And also, the acquisitions made sense and were done at a comparatively good price so I guess they are good lawnmowers with long-term plans (but terrible PR)?
Mr. Cantrill might be engaging in hyperbole. Big companies are big though- lots of people in charge of lots of things, and often they wander off in different directions. It doesn't make sense to model their behavior as if directed by a single hive mind.
Companies do have a culture though, the reason Amazon warehouse employees have to piss in a bottle can be traced back to Bezos and his laser like focus on controlling costs.
Big enough companies are the stereotypical paper clip AIs everyone fear, but with money. Anything seemingly moral action by them is simply a cost-analysis on how the public opinion will effect their profits.
I like Postgres but still turn to MySQL for production use most of the time for a few reasons:
* Permission management on Postgres is much more painful.
* The need for an external connection pooler makes postgres more annoying to set up.
* Better quality docs on performance tuning MySQL.
Do you really need a connection pooler for most PG installs? I run a SaaS company with a lot going on, and haven’t had to touch a pooler. Average about 500 open connections. That’s a few, but on a DB server with 200GB of memory it’s nots really breaking anything.
> * Permission management on Postgres is much more painful.
but way more flexible and powerful
I only work in the Java world where all application servers have the connection pooling built in, so I never had the need for an external connection pooler.
I joined a company where most stuff is done in Java and tried to explain to colleagues that sn external connection pool would ne good. They didn't know such things existed at all, and then refused because in their mind the application-specific intetnal pools were all they needed. Which was and is totally wrong - the application server internal pools, like HikariCP only share connections between threads inside the server. What if now we have 4 instances of the same server running (because of a deployment, where 2 new ones are spawned, started and the 2 old ones aren't taken down until the loadbalancer determines that the new o es are running ok. Now you need 2x the number of connections available than you would ususlly need. Once we had run out of connections when for some reason aws went crazy and started deploying too many instances of the application.
On Fedora/RHEL you get maria when you "install" mysql. I've never had something fail to "just work." That said I don't do anything crazy, so I'm sure there are cases where they don't work.
When I started working with databases about 20 years ago talking to peers it was common to have a layer in-front of the database so that you could easily replace the database. It felt stupid until I actually had to do a database migration... So do you still put a layer infront of the database so that you can for example easily change from mySQL to Postgress? Given there are so many open source database I think there is less need to do so... Or do you go all in vendor lock in? Or some middle ground?
I believe you are talking about the Microsoft ODBC API which was language and platform agnostic data acquisition layer. Early versions of it had pretty bad performance issues if I remember correctly, but eventually it became somewhat useful.
I believe that developers back in the 90's wanted a way to "drop in" various low and higher cost DBMS systems to their client-server based apps without the need of hiring full-time database sysops.
That would be an ORM or something similar, I think. It's not realistic unless you're always testing with two databases from the start, because their implementation details leak through.
It can be useful if your program is simple enough to work with both MySQL and SQLite, but often you should just stick with one DB and get to use all its features.
[ServiceStack OrmLite][1] does just that, all our development is done locally using SQLite but then deployments use MySQL. We do fall into the 'program is simple enough' category though.
You can indeed have that and many people do, but the problem with going that route is you can only use the lowest common denominator of features of any of the target databases, which wipes out a lot of the performance or convenience features you'd get from either.
(arguably SQL itself is/was supposed to be that common layer in the first place, but db vendors always want to be able to present users with new features that are not yet standardized)
I can see the business of open source software support coming to play as well. I went from freelance development to more of a govt contracting role and just recently pivoted my career back towards tech. I never saw this side of the business but it is thriving from where I sit.
mysql and MariaDB diverged from versions 5.6 and 10 respectively, although MariaDB can and does still merge some fixes from mysql; oracle don’t do that.
MariaDB and the original InnoDB developers are now doing heavy rewrites with big performance gains, replication options like multi-source, spider for sharding and galera are all built in and actively maintained.
Oracle attempted to extort anyone trying to licence a mysql based product(rip infobright), so infinidb and clustrix, now respectively called columnstore and xpand, have new homes with MariaDB and are core parts of the system.
Online schema changes, easy horizontal scale (huge numbers that make db2 and oracle sweat), s3 backed tables, non blocking backups, flashback, versioned tables.
The list goes on, and many industry veterans from ibm, oracle, sybase etc are finding a home there and helping MariaDB grow.
There are new public developer resources and the connectors are feature rich and well loved. There have been a few free online conferences during the pandemic, and MariaDB now has its own place at fosdem not just bundled in with mysql.
If you go enterprise, there isn’t much out there as accessible as maxscale for transaction failover!
I played with Spider in MariaDB 10.3, and it didn't satisfy the requirements we had, and it doesn't seem to have progressed significantly since then.
Yes, it's neat that MariaDB merged it and is keeping it working, but there don't seem to be many use cases where it ends up being significantly better than e.g. multi-source replication (the use cases where you're going to run out of disk, in most cases spider's un-implemented push-down join etc. make it too slow to be practical either).
> easy horizontal scale (huge numbers that make db2 and oracle sweat), s3 backed tables, non blocking backups,
MySQL has had "MySQL Enterprise Backup" for a long time. Percona wrote a similar implementation (XtraBackup), which works for MySQL, Percona, and MariaDB. AFAIK MariaDB copied XtraBackup as mariabackup (not criticising them for doing this, just pointing out that Percona did the original heavy lifting on this).
> flashback, versioned tables
Yep, versioned tables are a nice feature that I don't think are available in any other MySQL-like DB.
> If you go enterprise, there isn’t much out there as accessible as maxscale for transaction failover!
To be clear, I like MariaDB, but Oracle isn't doing a bad job on MySQL. MySQL 5.7 is pretty solid, and they have been improving defaults (while leaving the option to enable compat settings which are necessary when migrating a large deployment between versions), and MySQL 8.0 has some really nice improvements. For some of the best features from each, Percona (either standard Percona 8.0, which gives features like MariaDB's thread-pool, more comprehensive encryption including redo-logs etc., or XtraDB-Cluster to go with Galera instead of Innodb Cluster) offers quite a few benefits/improvements (and is contributing a lot of bugfixes/improvements upstream).
(My team runs quite a big installation, currently running Percona 5.7, and migrating to MariaDB probably won't be practical or justifiable considering replication compatibility which is a requirement to do no-downtime migrations)
What happened to MariaDB? Not much, but unlike Netbeans (which is a complete disaster under Apache... a dying project maintained by a skeleton crew), it still has a commercial entity behind it, so it's trucking along relatively nicely. I mean, it's not like Oracle is investing tremendous amounts of time and money into MySQL either... there are still many, many things in the MySQL ecosystem that are second class citizens when compared to the big boys. Features like materialized views are yet to materialize etc.
Well, when everyone and their dog is buying InteliJ licenses, most people that still care about doing FOSS work for Java IDE end up contributing to Eclipse instead.
Which is a pity, Netbeans is my favourite IDE and still has features hardly replicated in other Java IDEs, including the InteliJ Ultimate edition.
JetBrains would rather sell two licenses than allow for integrated development and debugging of native methods.
I do not think there was the time when MySQL was quite dead under Oracle ownership. As far as I aware Engineering team in particularly have only been steadily growing.
It is fair to say Oracle did not invest in ease of Oracle->MySQL migration but they have been making a steady progress on making MySQL better database for modern applications
MariaDB isn't even the only alternative. There's also Percona. From what I can tell all three have pretty decent followings and are actively developed, with some cross pollination.
>The 8.0 migration has taken a few years so far. We have converted many of our InnoDB replica sets to running entirely on 8.0.
At the scale of Facebook I wonder if they are the largest MySQL user on the planet.
And I take this opportunity to ask, does anyone know how does the MySQL roadmap works? What sort of features are coming or when is 9.0 expected to arrive.
So there has not been any major improvement in MySQL for 3 years? There hasn‘t been released any minor version? Can someone explain the current state more?
Sure, and this is great. But The newest release is 8.0.26, so there hasn‘t been any minor release yet - in 3 years. And i can‘t find anything about new MySQL features or planned features except the big 8.0 release.
In semantic versioning parlance those would all be considered "patch" releases, not a "minor" release. The minor version segment in a semantic version is the 2nd number, so most people would consider the next "minor release" for MySQL to be 8.1.0.
If following the guidance set out at https://semver.org, a patch release wouldn't add any new functionality, it would just address bugs in a backwards compatible way. A minor version would introduce new functionality in a way that doesn't violate backwards compatibility.
Quickly scanning the release notes for some of the MySQL 8 versions, they seem to be generally sticking to this; most of the versions fixed some bugs or unintuitive behavior, but it doesn't look like much new functionality has been introduced since 8.0.4, the last release candidate for the major version bump.
Many major new features have been introduced in 8.0 point releases. Some examples:
* 8.0.12 added INSTANT algorithm for adding new columns to a table
* 8.0.13 added DEFAULT expressions (column default values may now be any arbitrary expression, not just a constant)
* 8.0.16 added CHECK constraints
* 8.0.17 added the CLONE plugin for rapid physical copying of a db
* 8.0.23 added INVISIBLE columns (excluded from SELECT *)
These are just a handful among many others... basically MySQL 8 does not follow SemVer at all, nor does it claim to. (Although personally as a tool developer in the mysql ecosystem, I selfishly wish they did!)
No, since MySQL 8 doesn't ever claim to use SemVer. They have an explicitly stated policy of including features in point releases. Why would it be "pretty scary" that a non-SemVer software doesn't use SemVer?
SemVer is an arbitrary versioning scheme, not a universal standard. It's the operator's responsibility to understand the versioning scheme prior to upgrading.
It is pretty scary because most of these new features or enhancements are buggy. By not adopting SemVer, users of MySQL who prefer stability (oxymoron?) have no obvious upgrade path. They could be happily using version 8.0.123, and then upgrade to version 8.0.126 to get some security fix, and suddenly encounter a bunch of functionality and/or performance regressions.
Some examples...
WL#10310 Redo log optimization:
Feb 2018, initial commit 6be2fa0bdbba, landed in 8.0.11 (Apr 2018)
Jun 2018, crash regression fix commit 270d18368650, landed in 8.0.13 (Oct 2018)
WL#5655 - InnoDB: Separate doublewrite file to ensure atomic writes:
Dec 2019, initial commit ce14ef911, landed in 8.0.20 (Apr 2020)
Feb 2020, data loss regression fix commit c1bc61dc7, landed in 8.0.20 (Apr 2020)
May 2020, stall regression fix commit 00b284707, landed in 8.0.21 (Jul 2020)
In comparison, Cassandra during the DataStax days was extremely buggy, but at least it tried to follow SemVer. So the operators can follow some simple guideline, e.g. >=2.0.14 is fine, >=2.1.17 is fine, >=2.2.9 is fine. Of course regression can still happen, but that would be an exceptional case.
This is a misconception that new features introduce more bugs than eg. patches/minor version upgrades. I can only bring up the OpenJDK project as example but this sort of change happened there as well - what used to be JDK 8.xxx and everyone jumped to that without second thought is the exact same thing as JDK 9->10. It’s just management’s backwards thinking that somehow the former is safe to apply while the latter is not.
There is certainly no hard and fast rule. In the JDK case, in terms of language design, my observation is that with Brian Goetz in charge, it doesn't matter too much whether it was the slow release cycle back in the pre-9 days, or the shorter one from JDK 9 onward -- whenever a new feature is introduced, all kinds of compatibilities are being maintained at all costs.
(Except Project Jigsaw of course, but I'd like to think that he got overruled by his boss)
> Play with them on your laptop, but don't use a single feature, and wait for the LTS.
Personally I think the LTS model is great. Features get rolled out as soon as they are ready, and then get stabilized after being used by early adopters. Meanwhile, production can stay on LTS and continue to get just the necessary fixes.
In my experience, it is quite an exaggeration to claim that "most" post-GA 8.0 features or enhancements are buggy, especially in the general case. Yes, some of them may have edge-case bugs or performance issues, but typically only affecting some users with very specific environmental or workload situations.
Operators must test before upgrading. Luckily some third-party software makes this easier, e.g. Percona's pt-upgrade or ProxySQL's mirroring feature.
I'll state again unambiguously, I'm not personally fond of 8.0's release policy of rolling out new features post-GA. But I view it as an annoyance, and at least one with some upsides (not having to wait 2 years for a massive feature dump all at once) rather than being uniformly negative or "pretty scary". Personally I was careful about testing point release upgrades before 8.0, and I'm still careful about it now.
In another subthread, you're (justifiably) unhappy with how they didn't change the strict-mode default soon enough; but here you're upset that some defaults changed too fast?
Also my comment above in this subthread wasn't even about defaults. I only mentioned some features added, and you responded saying it's scary and then talking about defaults?
You don't like MySQL, I get it. Regardless of reasons, I don't think your view will change, so why enter every HN thread about MySQL just to repetitively bash MySQL? What's the purpose of this?
The purpose, mainly is to warn people of the pain I’ve suffered. My life should be a lesson here because honestly it is _painful_ to realise you have lost monetary data and have to go hat in hand to the CTO and CFO to explain why.
The strict mode setting should have been the default since the beginning. It is absolutely unthinkable that it wasn’t, the only justification I can think of is that:
a) it wasn’t built with that in mind and thus was experimental.
b) was not enabled to ease adoption (this is kinda evil, in my personal opinion because it teaches bad habits)
c) was considered a power-user feature, which is ridiculous.
What you’ve said just exemplifies the trend I’ve seen before: MySQL does not care about creating footguns, and people who have bought into the ecosystem like to exhalt that “you’re holding it wrong”- which is absolutely not a good warning.
If you listen to my rambling about the pain I’ve seen, and you still want to use it: at least it’s an informed decision. But pretending that all is well is not ideal, it doesn’t lead anyone to make better software or practices (MySQL) or better developers (because they don’t see footguns before they’ve sprung some self-inflicted wounds on themselves)
> The strict mode setting should have been the default since the beginning.
I absolutely agree with that. But what's the point in talking about a terrible default that changed nearly 6 years ago, literally over and over again, year after year?
> the only justification I can think of
The real answer is almost certainly "backwards compatibility". Same reason many things in Windows are non-ideal, for example.
Someone made a really bad technical decision early on, but fixing it overnight will break things for an utterly massive number of paying customers, so it can't be rectified without a slow transition plan. It happens.
Yes, it absolutely should have been fixed on a faster schedule regardless, given its importance. But just because it wasn't, doesn't mean that the entirety of the piece of software is hopelessly flawed and everyone involved in its development is an utter cretin. Especially when a piece of software is multiple decades in age and has gone through multiple corporate acquisitions.
> What you’ve said just exemplifies the trend I’ve seen before: MySQL does not care about creating footguns
What I've said? What footguns? I'm asking this honestly: what are you referring to? Let's recap this subthread:
* @taywrobel said "it doesn't look like much new functionality has been introduced since 8.0.4"
* I listed a number of new features introduced in 8.0 point releases, and explained that MySQL 8 is intentionally not doing SemVer
* You said "that's pretty scary" without ever elaborating on which specific thing I said you find scary
* I disagreed, given MySQL's stated written policy of not following SemVer
* You mentioned something about defaults changing (??? this wasn't even a topic I mentioned by that point in the subthread)
Now you're talking about footguns again, but the only one you're mentioning with any specificity was fixed many years ago.
> people who have bought into the ecosystem like to exhalt that “you’re holding it wrong”
Where has anyone said anything remotely like that in this subthread? Are you referring to my statement that the user should understand what's in an upgrade before upgrading? If so, I absolutely stand by that statement; it's utterly crazy to upgrade any database without even glancing at the release notes, let alone having a basic understanding of how the database vendor handles releases and versioning. This is operational basic practices 101, not about "holding it wrong".
And for what it's worth, "people who have bought into the ecosystem" includes a massive chunk of the S&P500 using MySQL as a primary data store. If it's as deficient as you claim, why aren't all these companies going out of business?
> Nobody expects defaults to change between patch/minor versions.
Can you provide an example of an application-side (IOW, not a DB-infrastructure-type variable) that has changed it's default in a patch version after GA in 5.7 or 8.0?
IIRC, all of the defaults changed in very early non-GA versions.
> Why would it be "pretty scary" that a non-SemVer software doesn't use SemVer?
Is there another level of patches below point releases for backported security patches, or are your options to upgrade to something that adds new features and may be backwards incompatible, leave your system vulnerable to known security wholes, or patch it yourself (or maybe depend on your distro to do itl
In practice, this is rarely a problem unless you're a cloud vendor with a DBaaS product; the most common concern there tends to be bugs that cause server crashes. But even that is fairly rare, and those platforms (AWS, GCP, Azure, Alibaba, etc) generally maintain custom patch sets anyway.
As far as I can recall, the vast majority of modern MySQL CVEs have been low severity and/or require the attacker to already be in your private network.
For sake of comparison -- does Postgres backport every security patch to every major.minor tree? And aren't HA Postgres upgrades generally more difficult than MySQL ones since logical replication is less widespread in the PG landscape?
> Is there another level of patches below point releases for backported security patches
No, because its unecessary (in my experience)
> or are your options to upgrade to something that adds new features and may be backwards incompatible
It won't be backwards incompatible, otherwise they would leave the change for a new minor release.
Why would you not want a new feature (e.g. the new "clone plugin") if it gives you value now without any migration required (because of incompatibilities that may arise if all new features are left for minor versions which are reserved for incompatibilities)?
> Why would you not want a new feature (e.g. the new "clone plugin")
Because features can introduce bugs or performance regressions. Sure you can say that's rare, but I still might not want to take that risk with some of the most critical infrastructure in my app.
SemVer is a relatively recent proposal that the vast majority of software does not follow. Calling the three parts of a three-part version “major”, “minor” and “patch” is a SemVer thing, not a universal standard.
> Python versions are numbered A.B.C or A.B. A is the major version number -- it is only incremented for major changes in functionality or source structure. B is the minor version number, incremented for less earth-shattering changes to a release. C is the patchlevel -- it is incremented for each new patch release.
There's also Windows with it's A.B.C.D or major.minor.patch.build version scheme. Not sure how far back that goes, but it clearly predates semver as well.
I'm coming to realize that semver is a lot like scrum. Everyone knows about it, lots of people like it, plenty of people want to use it, nobody seems able to move past arguing about how it's supposed to work and actually get a working implementation off the ground.
MySQL GA dates:
5.5 3 December 2010
5.6 5 February 2013
5.7 21 October 2015
8.0 19 April 2018
The average seems to be about 2.5 years between minor releases, so this doesn't seem unusual.
Usually new minor versions are only released if there are:
* Changes to database behaviour defaults (e.g. default sql mode)
* Deprecation or removal of features
* Compatibility changes (changes to replication formats)
New features are fine, as long as they don't introduce regressions in other areas.
Even MySQL 5.7 received some good improvements in the past 18-24 months (not just bug fixes).
I feel this is a really pedantic complaint from someone who either doesn't use MySQL, or wants to hate it for a silly reason.
> At the scale of Facebook I wonder if they are the largest MySQL user on the planet
I have to imagine they use other databases as well, right? We're much smaller than Facebook and we have some Mongo and some Postgres and a mix of Go/Rust/Scala/node.js.
I wonder how many boxes they have dedicated to be being MySQL machines. I wonder how big their tables are and how many writes per second they see during the day.
Their scale is enormous. I first heard the phrase "thundering herds" in a Facebook MySQL talk. (Thundering herds refers to what happens to your infra when something big happens in real life that lights up social networking/search/etc.)
> With roughly 2.85 billion monthly active users as of the first quarter of 2021
> 1.8 billion of Facebook users (66%) use the app on a daily basis
Say 1 database could store the data + handle the reads/writes for 100,000 users (literally just guessing)
2.85 billion monthly active users / 100k users per server = 28,500 servers/"instances" for MySQL
That's not even counting Kubernetes pods (if they use that) running Docker containers (if they use that) for their API / content serving.
I wonder what their average transactions per second looks like.
For Twitter:
> Every second, on average, around 6,000 tweets are tweeted on Twitter, which corresponds to over 350,000 tweets sent per minute, 500 million tweets per day and around 200 billion tweets per year.
> As of the first quarter of 2019, Twitter averaged 330 million monthly active users
Twitter has 11.5% the MAU of Facebook (330m of 2.85b)? I don't know if 1 tweet can be extrapolated to 1 Facebook like/comment/share/post but if it did, 6k tweets per sec * 8.7x the user base = 52.2k writes per second?
Found this:
> Facebook now has about 30,000 servers supporting its operations, hosts 80 billion photos, and serves up more than 600,000 photos to its users every second.
Facebook has purchased 6GW of renewable energy to power its datacenters [1]. Its datacenters have a PUE of about 1.06 last they published (they unfortunately seem to have taken their dashboards down) so that's about 5.6GW of electricity actually powering real load. Some of that will power the networking fabric so we could conservatively estimate 5GW of compute load. The OCP Yosemite v3 platform power budget is a max of 1.5kW [2]. Also conservatively, let's assume a real average 1kW load. I'll leave the division as an exercise for the reader to estimate the number of servers they operate.
Yes, and that's a conservative lower bound (their web application servers likely draw much less than a kilowatt each and constitute a healthy portion of the fleet).
The good news is that electricity still costs a lot, even at scale, so there is lots of financial incentive for hyperscalars to make their datacenters and computation maximally efficient. To wit: there are a lot of people at Facebook (and Google, and Amazon, and Microsoft, and Baidu....) who work on making their server code more efficient. Small changes can result in millions of dollars a year in savings (in electricity cost, infrastructure cost, and opportunity cost in not needing to procure more servers).
Probably because Youtube was using MySQL before being acquired and switched to a better, probably fully managed DB that was much easier (free?) to maintain and scale.
This is one of those scenarios where the answer is likely to be “both”, but I doubt you’ll get anyone discussing YouTube internal architecture in enough detail to be satisfying. Just look up what Vitesse is and compare what that implies in terms of operational complexity to using something like spanner if you want a straw man technical rationale.
google internally has always had a split mind about mysql. It never really jibed with the underlying google architecture but played an important role in multiple products (at least partly due to its replication features). Replacing it completely has turned out to be a huge challenge. I gained a fair amount of respect for mysql after seeing it applied at scale, but it was also a bit scary.
YouTube built Vitess, which lets you scale out MySQL writers. If I can scale out both my writers and my readers then what could be "vastly more scalable" than that?
It is designed from the ground-up to be globally distributed. Some other databases like FoundationDB (now owned and killed? by Apple) and CockroachDB were designed to scale across multiple datacenters.
Correction: FoundationDB is alive as open-source again, yay!
It was acquired by a huge company that sometimes kills products. Shortly after the acquisition, the downloads were removed from the website. It did go open source "recently" though which made it longer lasting, but I'd understand if someone would think it was dead by now.
As far as I can tell, Vitess still has trouble with cross-server transactions and distributed locking. Presumably something "vastly more scalable" could work around this.
The Spanner team noticeably put out https://cloud.google.com/blog/products/databases/inside-clou... a few years back, which tl;drs that they managed to get a reliable enough network that partitions don't really happen anymore and so you can get both C _and_ A from the CAP theorem. I don't think that Vitess is quite at that level, especially since you can self-host it and thus the devs don't have such network-level uptime guarantees.
Are cross-server transactions scalable? Would anyone architect a system that did them en masse unless they absolutely 100% had to?
I am just speculating here but I doubt that YouTube migrated to Spanner so that they could do cross-server transactions. I would think consolidating the Ops burden into the GCP org and also serving as a trophy "customer" were higher on the list of reasons. But again, just speculating...
Yeah, Google policy was to migrate everything to Spanner, not a technical decision.
> Are cross-server transactions scalable? Would anyone architect a system that did them en masse unless they absolutely 100% had to?
As a long time Vitess user and contributor/maintainer, this perfectly describes the issue. Minimal effort has been put into solving cross shard / 2PC transactions because a well designed system rarely needs it.
While "if it ain't broke, don't fix it" is often a perfectly valid approach, there are going to be times when an upgrade can result in significant performance improvements or fewer admin headaches.
Most product engineers interact with it by querying TAO, which you can read about in various blog posts, but is basically a cache in front of MySQL (this is a vast oversimplification).
Hi, Kevin. :) As of the time I left, the bulk storage system I worked on - images, video, machine-learning datasets, backups of other things, etc. - held most of the bytes at Facebook. The MySQL/TAO complex had orders of magnitude more addressable objects, undoubtedly handled many times more requests and bytes in flight per second, but when it comes to bytes at rest they're not even number one.
Basically all the small stuff. Every user's identity, preferences, history, and connections. If you post text, that's there too. If you post media, that's somewhere else. Connections are the hard part, because it's a gigantic graph with the potential to make every query - e.g. to construct a user's timeline - hit vast numbers of servers. There's all sorts of special sauce to do with partitioning, caching, etc. to absorb as much as possible of that load before it hits the MySQL servers, but it's still a gigantic service even by Facebook standards.
The MySQL 8.0 upgrade is not a migration to Oracle. Facebook has run MySQL for many years at this point and, as the article describes, operates on a private fork. They have employed some of the leading engineers in the MySQL community to support their version of MySQL.
It's a stretch to claim this is a "migration". Facebook has used MySQL since its very early days — certainly since before Oracle acquired Sun and thus MySQL AB.
I guess one could dream of the remote possibility that Facebook outright acquires Oracle. It seems like a weird match, but it'd give FB a toehold in a lot of verticals that it currently has no presence in. Whatever criticisms you have of FB, it's at least a pretty open source friendly company.
Facebook has no interest in infrastructure / enterprise revenue streams (Facebook for Work notwithstanding). See the history of Asana, Cloudera and Phabricator (and even Dropbox, from an employee/recruiting perspective, kinda).
Oracle has a very complete and much cheaper cloud solution relative to AWS. I've begun migrating my own projects over to their cloud. The savings on egress costs alone pays dividends.
> Once something gets bought by them, you know it is done. Slowly, but surely.
> They perform a function akin to the maggots that destroy cadavers in nature. Part of the overall ecosystem.
> ORA stopped being a tech co a while ago, now it is a finance play. Use cash to buy a business for its locked in customers, gut it to squeeze max money out of it until last customer is gone. Rinse, repeat.
And yet MySQL is very much alive..? Java has fully opensource implementations too, and has had innovations like GraalVM and Jakarta EE.
I think I'm too young to hate Oracle with a burning passion. I would be very scared of their sales/corporate team, but I mean, even having large contracts with Google or Amazon is difficult to say the least.
MySQL is alive for companies already using MySQL, but would well informed companies be choosing it today? I'm not so sure.
I think you either want it to have more functionality and you choose Postgres, you want a particular performance profile and you pick MariaDB, or you want the enterprise support and you pick Oracle's database. Why you would pick Oracle-supported MySQL today I'm not sure.
PostgreSQL still after all these years has a terrible story when it comes to HA and horizontal scalability. Nothing is built in or supported. And one of the only companies to provide something half decent i.e. Citus is now owned by Microsoft and so that project is now at risk.
With MySQL group replication, it is pretty easy to set up a HA cluster that allows you to sleep soundly. It can also handle thousands of connections without the need of a connection pooler.
I think so, but they have been operating MySQL at scale for many products for about 20 years, so I can understand why they might not choose MariaDB (or Postgres, Oracle, etc).
This is not so with Java. They have moved Java along a lot since they bought it; they released 1.8 finally, and have introduced lots of new features such as type inference since then.
MySQL is also going strong after the acquisition. Lots of new features.
I work for a government agency in a rather poor flyover state. We ran Oracle databases and a few other products for multiple decades, until Oracle conducted an audit and decided to shake us down for everything we were worth. We migrated away from their products, but only after being forced into expensive multi-year subscriptions for products that we didn't need.
I will never forget the arrogance and greed of their legal/sales people. They are bloodsucking sociopaths.
I'm no fan of oracle's audit approach but it sounds like you were expecting special leniency to not pay for their stuff - for decades - because you are a govt agency/ live in a low income place. Not how business works. If you're playing by the rules, no one can force you into any long term contracts you don't need.
I'm also a government Oracle dev. I have no way of knowing what I'm licensed for and they don't disable the features we're not licensed for. I literally have to talk to my director to talk to our account rep to figure out that I'm not allowed to use table partitioning.
portions of Salesforce are the same way. You don't know you're out of compliance until an audit happens and you get the "sure would be a shame if something happened to your instance..." speech.
Agreed that Oracle licensing is byzantine, probably deliberately. But devil's advocate says that any organization should be aware of what they are actually licensed for, even if that means contracting a third party to ensure compliance.
We have a small IT department and are running on extremely limited funds. We literally had two unlicensed dev databases, and Oracle threatened to sue us for millions of dollars, unless we bought a subscription to their shitty cloud product.
The whole process was shitty, predatory, and abusive.
That’s the usual blind rhetoric against Oracle. Any factual info on how are they worse than the “good” companies that literally track every single step you take, that attack the very democracy of countries, that help the spread of dangerous anti-intellectual rhetorics, or the “usual” anti-union, shitty working condition giants?
They dared sue the small mom&pop shop called Google for going against the Sun license of Java?
Microsoft. King of the enterprise with no intention of losing the title.
PowerApps, Power Automate etc. - while not necessarily innovative in a vacuum - are, when you consider they are bringing cloud-based automation and RPC to the (enterprise) masses.
Totally off topic, but I found it funny that in the offical oracle cloud intro video the robot arm in the background misses the box, right as the narrator mentions the advantages of automation at 1:10: https://www.youtube.com/watch?v=f_BDfMdGn3M&t=61s
It's all on their site - https://www.oracle.com/cloud/ Their price list is at https://www.oracle.com/cloud/price-list.html and the egress is under the "networking" section. Basically they give you 10TB outbound data transfer for free and charge as little as $0.0085 per GB after that. That's a savings of 90% (or 100% if you use less than 10TB transfer, which most apps do)
Additionally their cloud servers (and most other services as well) are much cheaper than comparble EC2 instances and every one of their services I've used so far also includes a free tier so you can try them out without paying anything.
Yeah, AWS (and Azure, and GCP) really has notoriously expensive bandwidth, and it's the one thing they will never budge on in negotiations, since they know it's where they have nearly 100% profit margin; you can avoid using most services, or use compute etc more efficiently, but it's hard to consume less bandwidth!
It sounds like Oracle is actually pricing bandwidth at a reasonable price. This is quite a shock, coming from a historical perspective!
Wow. I worked on the upgrade from 5.0 to 5.1 (I think). We had fewer than 100 patches at the time. 1700 sounds like a nightmare. I apologize for any and all of the patches I wrote.
> MySQL, an open source database developed by Oracle
This makes it sound like Oracle created it, when it fact the reality is the opposite: Oracle fought it, and bought Sun just so they could get their hands on MySQL. How did regulators let that happen is beyond me.
No. The most valuable part of sun at the time was arguably the SPARC chip architecture and Solaris which gave Oracle a vertical compute platform to compete with IBM Db2 on POWER running AIX. In our new cloud world this is now quaint and irrelevant but it was a big deal when on-prem was the only way.
>It took a couple of years to complete porting all of these features. By the time we got to the end, we had evaluated more than 2,300 patches and ported 1,500 of those to 8.0.
This is some tremendous effort as I see. I wonder how many people work on these evaluations.
Well...I love MySQL but there was a time when it was anything but rock solid. It was pretty painful until InnoDB replaced MyISAM in 2010 as the default storage engine. After that it became rare to lose data.
Don't get me wrong, there are still occasional problems. Most of those I've encountered have been applications misusing MySQL. We can debate whose fault that is.
But at least people stopped doing REPAIR TABLE after hard restarts of MySQL. It's been a long time since I last had to do that.
I love MariaDB/MySQL. I had only like 2 crashes and 1 broken migration over the decade of it in production. It very powerful if you design tables and indices right. Postgres may be great too but I started with MySQL and I don't want to work with more DBs in parallel as there are quite a lot of differences for some queries. And I don't have capacity to write all queries in two forms. :D ORM is universal but doesn't always do queries optimally. And fulltext works completely differently between the two, for example.
Anyone else puzzled by the shaking migration animation?
The original file has a 1920x1080 resolution. I wonder if it is related to the shaking.
Good article nevertheless.
I didn't downvote you, but you were downvoted for this. So maybe I'll explain further, instead, to stir conversation.
As you deal with more and more rows, it becomes imperative that all of your where clauses hit indexes/indices, but even beyond that, with large enough row sizes, it's not enough to provide fast responses.
I suspect they deal with this in the form of some sort of caching outside of MySQL, but I haven't read into it.
I'd be curious about how you respond to such challenges at the billions or trillions of rows orders of magnitude. Millions can be difficult enough, but beyond that you may have queries that effectively never return if you do not plan.
Facebook is heavily sharded, which keeps the size of each physical table at reasonable levels.
Similar story at nearly every large tech company using MySQL, aside from some more recent ones that go for the painful "shove everything in a huge singular AWS Aurora instance" approach :)
Aurora lets you grow your db storage up to 128 TB, but things become difficult and slow long before this point. This is true operationally (e.g. schema changes, restoring from a backup, etc) as well as potentially for application / query performance issues.
That said, sharding can be very painful too in other ways. But at least it permits infinite horizontal scaling, and it makes many operational tasks easier since they can be performed more granularly on each smaller shard.
Besides, once you get anywhere near Aurora's storage limit, you'll need to shard anyway. So it really just buys you some time before the inevitable.
My old-man brain still can't compute this statement: "MySQL, an open source database developed by Oracle". I know this is now factually true, but late-90s me keeps looking over my shoulder and freaking out.
I think MySQL Engineering team does great job with Engineering, Do not want to deal with Oracle Sales ? I would invite you to talk to Percona for Commercial Support and Services Options
I got sad when I read that TokuDB in Percona & MariaDB was being dropped :(
Replaced TokuDB with MyRocks but it's totally different => now finally managed to have good ~constant performance insert&deletes (had to test & tune a lot), but "updates" remain a problem (they write a lot as I understand that any update always has to rewrite the entire row).
Using InnoDb instead of MyRocks is NOK for me (problems with deletes and related hole punching + bad that tables can never shrink when stuff gets deleted), I don't see other alternatives... .
I'm now experimenting with other DBs (right now with CockroachDB but it doesn't seem to be very stable, might then try as well Postgres but I'm scared by the lack of SQL-hints to cover worst case scenarios).
This might change everything for me. I'm already using MariaDB+MyRocks and Clickhouse for some special/dedicated tasks, but I was really missing a good DB for normal/typical OLTP tasks.
So far I used (as mentioned above) MariaDb+TokuDB (but the optimizer of MariaDB can be a bit crazy from time to time), had multiple times during the past months thoughts about PostgreSQL but the lack of hints always made me take a step back from it => this addon seems to be exactly what I wished for.
Looks like that my weekend will be all about PG - the last time that I set it up its version number had a single digit => cannot remember anything anymore... .
I just configured a new router and had to set up my dynamic DNS updating service on it.
Went to dyn.com and the goddamn website is gone, redirects to some corporate Oracle bullshit and PR, and I can't login to that Oracle crap with my dyn.com account and password.
In case any confused people googling for this stumble upon this comment you need to go to: account.dyn.com which they don't tell you on the Oracle page.
You can log in there with your former dyn.com credentials.
Not relevant to the original topic, but yeah. I'm still an individual, private user of dyn, and when oracle bought them, what they charge me jumped significantly. Moving to another provider is just low enough on my priority list that it has happened yet, but I'm not happy about it.
Traditionally, part of what made it worth paying IBM prices was reliably top-notch service, but perhaps that changed over time. What were your experiences? And which decade?
I can't read pass "developed by Oracle". It is factually not true. Unless there's so much code change after the acquisition that there's no single trace of the original open source version of MySQL left in there.
MySQL always was primarily developed by an commercial entity. And always gave an license out under GPL (i believe very first used some other license as GPL wasn't known back then ...) Oracle took over the development team (lots of pre-acquisition staff included) and legal rights to all of that.
(Disclaimer: I started at independent MySQL AB more than ten years ago and now wear an Oracle badge, after wearing Sun for a while)
Maybe it's legal talk that I don't understand, but the fact that Oracle owns the majority of the dev team today, doesn't mean Oracle developed MySQL. Because at the time MySQL was "developed", Oracle didn't own MySQL, nor did Oracle "own" the developers.
Oracle still develops and to a notable number the same people. Also Oracle steered 8.0 which was a big change to internals. Anyways won't argue about single words.
Agreed. And in one sense (English is complicated) it's not true in its most obvious interpretation—that Oracle is the reason it exists. It was developed by others. Changing it to "currently being developed by Oracle." It's not that "developed by" can't mean "currently being developed by." It just isn't the most obvious meaning.
I had the same reaction! I was like, “technically, yes, but…”
I haven’t thought about MySQL proper in years, but it is interesting Facebook is moving to MySQL 8 rather than going to MariaDB, which as far as I know, had MyRocks built-in.
> A few applications hit repeatable-read transaction deadlocks involving insert … on duplicate key queries on InnoDB. 5.6 had a bug which was corrected in 8.0, but the fix increased the likelihood of transaction deadlocks.
Interesting, I've run into a bug in MySQL 5.6 involving select for update where it deadlocked when it shouldn't. I wonder if the two were related.
Where can I read more about the custom things FB added to MySQL 5.6? Their work on replication and the DDL work seems fascinating. Are there scholarly papers, white-papers, blogs?
I've not got a FB account due to reservations about FB and their business model but that doesn't mean I am above learning from what they do, thanks for the link, I'll have to find info elsewhere though.
I don't think you need a FB account to read the posts there, you can just treat it like a blog with a crappy interface (but very good content). Probably some mandate to "eat your own dog food".
> First, we could not upgrade servers in place and needed to use logical dump and restore to build a new server. However, for very large mysqld instances, this can take many days on a live production server and this fragile process will likely be interrupted before it can complete.
This part is quite interesting. I'd think it will take maybe a day to dump/restore a database with a single 10TB table with no parallelism, at a speed of about 120MB/s. How big is these mysqld instances such that the process will take many days?
It's my opinion that schema changes should be cheap, fast and unexciting.
Unfortunately, in my experience once you are operating at scale they are expensive, slow and fraught with peril.
The result is that engineering teams often chose to build poorly designed schemas and take on technical debt rather than make a schema change to a core table. This is a terrible anti-pattern!
I'm massively in favour of anything that makes schema changes cheaper and more boring. I really enjoy working with the Django schema migration system for this reason - though it won't help you as much if you need to make schema changes to older versions of MySQL (I've not tried schema changes against 8.0 yet) since you'll likely still need to use GitHub ghost or Percona pt-online-schema-change.
I would have very few cases where that works for me. Because I almost always need the database layer to continue to work for a time with both the old code and the new code update. Deployments usually roll out to pods a few at a time so changing the schema of a table suddenly will immediately throw errors all over the place.
I've been contemplating adding a JSON column to all of my tables just to provide somewhere that covers those cases - still controlled with source-code level validation and with the expectation that any column which needs to be used for filtering rows gets promoted to "real column" status.
I'd much rather use a robust, performant real schema migrations tool though.
Schema changes are pretty much the riskiest damn thing you can do with a database, so it's natural people would be extremely interested in being able to confine as much of that as possible to transactions, even if changes are rare (which, arguably, they're rare in no small part because they're so risky).
> But why? Are you making schema changes that frequently?
Because it makes the migrations much more robust and way easier to develop & test.
If something goes wrong in a migration script, everything is rolled back. You edit the part that caused the error and simply run the whole script again.
And despite of thorough testing, there is always the possibility that it fails when applied in production. You want that migration to be completely successful or not at all.
Think e.g. splitting a table into two (which also includes DML) or moving columns around while creating new foreign keys.
You might not need to put the whole migration into a single transaction, but at least combine some steps into one - but this is only possible if the DDL statements are transactional.
I would have had problems too if this was early 2010s, but I mean Oracle has been developing MySQL for more than a decade now, so I think it is fair to say "developed by Oracle".
It didn't say originally developed by Oracle. The statement is accurate; MySQL is currently developed by Oracle.
At big companies, sometimes the corporate lawyers are overly picky about wording in blog posts and public presentations, e.g. "make it clearer that MySQL isn't our in-house product" type of thing.
fwiw, several of FB's top database folks originally worked for MySQL AB, so they're well aware of the development history.
I'd be interested more in what features were in their (3):
> Non-MyRocks Server: Features in the mysqld server that were not related to our MyRocks storage engine were ported.
i.e. things that they haven't shared with the MySQL community but aren't related to the storage layer. Why would/should they keep those private? Considering that RocksDB is open-source, clearly it's unlikely it's because they're 'trade secrets'.
Only commenting to say their site makes me mad cause it breaks the browser history. I click the link, go to the fb engineering site, and the back button has no history to go back to HN. Dark Pattern UX -- gross.
Can’t confirm. It works exactly as expected in Firefox (private mode because FB links open in the FB container otherwise), so maybe it’s some extension you have installed? FB Engineering links are usually pretty clean, and they don’t even have a reason to try and keep you there.
> MySQL, an open source database developed by Oracle
Dear Facebook:
Please fix the wording emphasized above ASAP before we revolt here in outrage with your lack of attention to detail. MySQL was developed by relevant open source project contributors (initially, MySQL AB folks), but not by Oracle and even not by Sun Microsystems. MySQL has been in development for ~12 years before Sun acquired MySQL AB. Please set the record straight.
Sincerely,
MySQL user (not currently, but in the past and maybe in the future [though unlikely, because Postgre...] :-)
