Forking MySQL/ for how long can forks keep up?

• Fact: MySQL 5.6 was released as GA in February 2013
• Fact: MySQL 5.6 has been available with its complete set of features since September 2012
• Fact: On September 21st, Oracle has released MySQL 5.7.2, which is the de facto major release after MySQL 5.6 (5.7.1 was just a token “we’re-still-in-business” release).
• Fact: As of today, there is no GA-ready fork of MySQL 5.6.

Percona Server is still in RC state, while MariaDB, with its runaway version 10, is still in alpha state. Of these releases, Percona Server seems the one in the better shape. Their problem was to adapt Percona Server to the enhanced codebase for 5.6, and the merging problems were bigger than the ones encountered in 5.1 and 5.5. Percona Server is a business oriented fork. It includes specific features for performance and manageability, things that users are asking for, and things that make Percona professional services easier to carry out.

Much different is the case of MariaDB. Their feature set is wider and hard to categorize globally. It includes some features that enhance performance (block commit, subquery optimization) but also plenty of features that are included only because nobody else wanted to touch them. In my experience, adding features to a project does not make it more stable, as the MySQL team knows well, with its disastrous experience with version 6.0, which was aborted after two years of alpha. MariaDB is in a state where they are adding lots of stuff to their code base, while merging selected pieces from MySQL 5.6. It could be a recipe for success or disaster. User experience will tell.

Up to MySQL 5.5, MariaDB has kept itself completely compatible with MySQL, with the goal of being a drop-in replacement. With the capriciously numbered version 10, that promise of compatibility has been broken. Most of the features introduced in MySQL 5.6 have not been included in MariaDB 10. Some of them have been rewritten with a completely different approach. As a result, MariaDb 10 lacks some of MySQL 5.6 features (parallel replication, for example) while showing some that are not in the upstream project (multi-source replication). The design of GTID has been started from scratch, and surely will make interoperability really hard (if not downright impossible) between the two projects.

Looking at the status of the projects, it seems that the MySQL team at Oracle has produced so many changes, that keeping up with it, even in terms of simple patch merging, is a heavy task. Where does it leave us, the community users? We have the choice between using the latest and greatest from Oracle, or waiting for the next latest and greatest from one of the forks. Percona Server seems to be on the final path of a less-than-easy catch-up, but MariaDB is farther away. And even if it releases a GA soon, it will find itself in a situation where merging changes from Oracle is going to be tougher and tougher. It may mean that performance enhancements from mainstream MySQL will take months (or years) to reach MariaDB. Users willing to benefit from the latest improvements will choose between Oracle MySQL and (with some delay) Percona Server. MariaDB will need to either do some sort of cherry-picking from Oracle releases or implement its own improvements. Can they compete with the 200 strong engineering team at Oracle? It’s going to be a tough proposition.

Given the above facts, how is it that we hear of big players like Red Hat and Google announcing that they will adopt MariaDB instead of Oracle’s MySQL? Since I could not find a sensible technical reason, I am forced to conclude that the choice has been political. Both Red Hat and Google have been entangled in commercial competition, and sometimes in court. Yet, choosing software for non-technical reason looks foolish to me.

Summing up: Oracle is releasing a steady stream of improvement for MySQL. This shows a high level of commitment that does not play well with what the doomsayers have been announcing for the past 4 years. So far, facts are contradicting that FUD. Forks are lagging behind. Some more than others.

Disclaimer: The above thoughts are my own, and don’t reflect the opinions of my employer or other companies.

Who's afraid of MySQL forks?

There is much talk about MySQL forks and how they are going to replace MySQL, or take over MySQL user base, or become more powerful/profitable/popular/you-name-it than MySQL itself. Let's clear some air on this topic. There is more about forks than meets the eye, especially if you think about a few obvious facts. What's a fork? According to Wikipedia a project fork happens when developers take a legal copy of source code from one software package and start independent development on it, creating a distinct piece of software.

By this definition, when someone who doesn't work at the MySQL project distributes a package that is based on MySQL code but differs from the original, it's a fork.
Why am I approaching the issue from this angle? Because, apart from Windows users, who mostly download MySQL from the official site, the majority of users get MySQL through a Linux distribution or some other project. And most of the time such packages are different from the ones built by the MySQL team. There is nothing wrong with that. The differences are sometimes minimal packaging changes done to adapt MySQL to the specific distribution, and sometimes they are a cherry-picking application of patches to an old version that needs to be maintained so that the package is unlike any other MySQL version that you may find in the wild. Even if the version is the same, depending on the distribution and the age of the server, the code beneath could be wildly different from the official versions.
Thus, it turns out that many users, possibly the majority, are using a MySQL fork, albeit a very minor one.
But when people talk about forks, they often refer to three main projects:

• The Percona distribution. This is a collection of a few distinct patches in the server, coupled with a fork of the InnoDB plugin, named XtraDB, and an independent tool for backup (XtraBackup). This fork has a solid business background. Every patch has been developed to meet user requests, and the engineers at Percona maintain them appropriately.
• Then we have the MariaDB fork, which is a series of changes to the MySQL core, motivated by the desire of the developers to build a rich set of feature enhancements while being backward compatible to the main distribution. The business model is thus a fast track of new features and bug fixes to customers.
• And then there is Drizzle, which has even less business traction than MariaDB, but a very well defined goal of creating a lightweight database by re-engineering a bare bones stripped down version of MySQL that is now very distant from its origins.

What I said in the above descriptions is just the synopsis of what these three forks are. In recent mythology, it is fabled that, if MySQL ceases to exist (because it goes bankrupt, or Oracle kills it, or a major accident happens to the project, whatever) users can replace MySQL with one fork, and live happily ever after.
Not so fast. There is something that few people take into account when listening to this too often repeated tale.
What most observers miss is that the forks' original code (with the exception of Drizzle) is very marginal. The bulk of the distribution is still the code produced by the MySQL team, which is merged at every minor release, and integrated with the patches produced by Percona and MariaDB. So, while technically they are forks of MySQL, they can't live independently from the official MySQL distribution. Both Percona and MariaDB don't have the manpower to maintain the server by handling the huge amount of bugs that the MySQL team is fixing every month.
There is also a matter of skill set. Percona has talented InnoDB experts, while MariaDB has mostly core server experts (and some are among the top ones, I may add). They could complement each other, although it seems that cooperation between the two projects is not as good as it used to be. (Could be my personal impression.)
The bottom line, though, is if both projects are able to survive should the main project become unavailable. I am not suggesting that Oracle wants to make MySQL scarce. On the contrary, all the information at my disposal suggest that Oracle will keep MySQL publicly available for long time.
This state of affair seems to indicate that Drizzle is, instead, a true fork that does not depend on MySQL health. To some extent, this is true. However, the main storage engine in Drizzle is InnoDB. Therefore, at least today, Drizzle is as dependent on Oracle as Percona and MariaDB.
What would happen tomorrow, if the disaster depicted by doomsday advocates comes true and MySQL actually disappears? I don't honestly know, but I would love to have a public commitment from the major players, about what they are prepared to do in terms of maintaining that huge chunk of code that today they take from Oracle releases on a monthly basis.
This is all matter of thought for MySQL users.

About adoption of the forks today, I have seen five types of arguments in favor of a MySQL fork:

1. I need the feature provided by Percona or MariaDB, or I need a quick bug fix that I can't get from the slow roadmap at Oracle. I trust that this handful of people are able to maintain that little code that differs from MySQL and matters to me. So I don't care if they don't have 100 developers on the task.
2. Given Oracle's track record in other Open Source projects, I don't trust them to deliver MySQL according to FOSS principles, so let's go for true Open Source alternatives.
3. Most MySQL developers have now left Oracle, and so the forks have more chances of being higher quality.
4. Cool! MariaDB/Percona has a bunch of features more than MySQL. It must be better. Let's use it.
5. I like new technology. Let's plunge into them!

Argument #1 is a solid business backed reason for adopting some software. The risk is often well calculated, especially if the evaluation can be backed by performance and functional tests.
Argument #2 is frivolous, as it mixes subjective feelings into business matters. And so is argument #4. Yet, these two types of advocacy are quite popular and spread much faster than the more reasonable approach seen at #1.
Argument #3 is debatable. MySQL developers at Oracle outnumber all forks easily. The idea that the departure of a few core developers can alter the system in such a way that the whole project crumble has been already negated by facts: MySQL 5.5 is an excellent release, with enthusiastic appreciation from power users. While I agree that top MySQL talents work at the forks, I consider the MySQL team to be still in excellent shape.
Argument #5 is reasonable, if it is followed by cool judgment and backed by facts. I am one who is always ready to try new solutions, and love experimenting with cool technology. But adoption is different from proof of concept. I am happy to see that Drizzle can replace MySQL in some applications, but would I trust it in its present beta stage? Certainly not. So, I am happy to test, but I trust my valuable data to more stable solutions.

What's for you, the final user? My personal advice is: don't adopt blindly because of some enthusiastic advertising. But test the product thoroughly, and if it fits your needs, by all means, go for it. But if you don't have a specific reason, I recommend staying with the official branch, because, despite the change in affiliation, there is still a well experienced team behind it.