gh-ost VS janet

I’ve been through multiple incidents where everything worked fine in the testing environment but ended up locking the production database for minutes when deployed. A category of open-source tools called OSC (Online Schema Change) exists to mitigate such pain, like gh-ost used by GitHub and OSC used by Meta. They work by creating a set of "ghost tables" to apply the migrations, copy over old data from the original tables, and catch up with new writes simultaneously. When all old data is migrated, you can trigger a cutover to make the "ghost tables" production. Check the post below for a great introduction and comparison:

Sounds like it's basically explained in the gh-ost readme https://github.com/github/gh-ost#how

I think it amounts to "use views to decouple access to the table with a fixed interface" and "use triggers for migrating data between tables"

Gh-ost is the new hotness. Simple to use and lots of great features: https://github.com/github/gh-ost

If the performance of the db is a concern during migrations (locking, high cpu consumption for large writes) there are tools that can help and do similiar to what your describing but with the benefit that they are battle tested tools. This one spring to mind https://github.com/github/gh-ost there are other options as well and its worth reading the trade off docs

Not sure which version of MySQL you're using, but one approach would be to use a tool like pt-online-schema-change (from Percona) or g-host -- which will create a duplicate table and then swap it in place of the original table. It's a safer approach when operating in production environments. Here's a good comparison of the tools many people use https://planetscale.com/docs/learn/online-schema-change-tools-comparison

No, especially on large tables with billions of records. They make online schema changes impossible. More details: https://github.com/github/gh-ost/issues/331#issuecomment-266...

Tip #4: Consider slow-running migrations. Some tables can be so large that the traditional migration way is simply not a viable option for them. In such cases, you can consider embedding the data migration code right into your application, or use a special utility like GitHub's online schema migration for MySQL. A slow-running migration can work in production for days or even weeks. It gradually converts the data by small chunks, so you can carefully balance the load on the database while making sure that it doesn't cause slowness or downtime.

GitHub gh-ost

Actually I never tried but I was scared by the small print of GH not using RDS themselves [1] and Ghost relying on lower-level features that might be not easily available in RDS. Also I had the impression you have to setup a normal non-RDS replica attached to your RDS master?

[1] https://github.com/github/gh-ost/blob/master/doc/rds.md

Seems like a perfect use-case for Janet. (https://janet-lang.org/) A fast minimal VM like Lua, but even more extensible than Lua by being a "Lisp" with macro and C extension capabilities. Not a true Lisp, it's very pragmatic and performance-oriented. But it keeps the good stuff.

You might be looking for: https://janet-lang.org/

It comes with a build tool `jpm` which installs dependencies globally by default, but you can have it be installed in your project folder as well.

I like Clojure, but I never had any good opportunities to use it other than for a few small hobby projects. It is unfortunate that it is so huge with tons of dependencies and no simpler native implementation. I started looking at various LISPs and Schemes to find something lighter to use instead and ended up settling for Janet that I think is Clojure-like enough to be comfortable to use, but in a small native binary with no dependencies and can be embedded in other native programs. I am sure for big, real, projects that Clojure makes more sense, but for my hobby projects and scripts I do not think I will install it again. I am still happy for the things I learned from learning Clojure. It was a real eye-opener for an old OO-programmer.

https://janet-lang.org/

One might also check out Janet for quick scripting tasks.

https://janet-lang.org

Thanks!

I thought about another multiplatform, homoiconic, highly compact language: https://janet-lang.org/ (takes 803 kb on my machine).

It has no types though.

Racket is great, and if you like it you might find Rash interesting:

https://rash-lang.org/

Janet and Gerbil Scheme are also worth a look:

https://janet-lang.org/

https://cons.io/

Point here is that, for instance Janet language does not have cons / pair type but tuple (and so is lispoid, not lisp), but clearly this is sufficient for macros & hence seamless language construction: all you need is to be a lispoid although being a lisp gives another useful feature.