> I also wrongly assumed that it was pt-osc, because that's what get mentioned at your website

I said Skeema was inspired by Facebook's approach to schema change agility. It was not implemented by Facebook. It is not a Facebook project, it does not use any Facebook tech. Facebook does not use Skeema.

> there's always a risk that the additional write operations would trigger a production incident due to replication lag

fb-osc bypasses replication entirely. Read the links I provided previously. The 2010 post was written by Mark.

As I said already, fb-osc was used dozens of times per day across Facebook's mysql fleet. Its design was influenced by some of the very people you're name-dropping. It ran seamlessly as part of a self-service declarative schema change automation system.

I was a former member of the team that was directly on-call for all MySQL incidents at Facebook. I am discussing my direct personal experience here. There were certainly some particular repeat-causes of oncall misery, and plenty of oncall shifts that were 12+ hours of hell. Yet I can't recall a single major incident that was caused by online schema change during my time at Facebook.

> The experimental write-set replication in MySQL 8.0

Nothing "experimental" about that feature. As a consultant I've directly used it to speed up parallel replication at major companies that you've very likely heard of.

> You do realize that you are the only one defending MySQL here right?

That statement is demonstrably false. There are several other commenters defending mysql in this overall thread.

Anyway, I'm in good company: the corporations using MySQL make up several trillion dollars of combined market cap. If you have any s&p500 index funds, you are heavily invested in MySQL's successful use, whether you like it or not.

> have very high respect for Domas, Yoshinori, Mark, and Harrison

Yes, these four are superstars, among others. I don't understand how you say you have very high respect for them, yet you're fine with crapping all over the database technology they all spent a large chunk of their lives working on. All four previously worked for MySQL AB, Sun, and/or Oracle.

> I can't take you seriously if you think that the DB engineers would carry out such a risky move of rewriting all tables by changing the storage engine with ALTER TABLE.

Where did I say anything about doing this migration using ALTER TABLE? You keep responding to things I did not say or even imply!

I said the MyRocks migration is an example of schema change across all of UDB, in response to your claims that UDB was somehow static and did not need any schema changes.

Storage engine is part of table schema, both logically and physically. Changing storage engine is a schema change, regardless of how you accomplish it: ALTER TABLE, or trigger-based OSC tool, or RBR-based OSC tool, or old-fashioned replica swaps, or dump-and-reload as done in this case. You gloss over this by saying "some MyRocks replicas were provisioned" -- this is the schema change step, via dump-and-reload!

> It is a technical discussion, not a competition

Is it? Your approach to "technical discussion" apparently involves arguing against people's direct lived experiences; arguing about technology that you have no hands-on experience with; and arguing against strawmen points that were never made in the first place.

You keep name-dropping my former coworkers who you claim to respect, yet you post with a throwaway pseudonym.

I do not believe you are engaging in a good-faith technical discussion, so I will not be responding further.