departure
Percona's pt-online-schema-change runner for ActiveRecord migrations. (by departurerb)
gh-ost
GitHub's Online Schema-migration Tool for MySQL (by github)
departure | gh-ost | |
---|---|---|
1 | 32 | |
134 | 12,010 | |
0.0% | 0.6% | |
8.0 | 7.5 | |
2 months ago | 6 days ago | |
Ruby | Go | |
GNU General Public License v3.0 or later | MIT License |
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
departure
Posts with mentions or reviews of departure.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2022-05-04.
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Changing Tires at 100mph: A Guide to Zero Downtime Migrations
At least for Rails there are several gems available (ie https://github.com/WeTransfer/ghost_adapter or https://github.com/departurerb/departure) that seamlessly hook into the existing migration system and will run all eligible migrations through gh-ost or pt-osc as needed. You're right that it's not free but it isn't all that far off either.
That said, online schema migrations are a specialized tool designed for very big tables that take hours to run an ALTER TABLE on. If all your tables are small enough that alterations take less than a second or so, don't bother and just block the table for a bit. It's fine.
gh-ost
Posts with mentions or reviews of gh-ost.
We have used some of these posts to build our list of alternatives
and similar projects. The last one was on 2023-12-08.
- "At GitHub we do not use foreign keys, ever, anywhere"
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How Modern SQL Databases Are Changing Web Development - #3 Better Developer Experience
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:
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We migrated to SQL. Our biggest learning? Don't use Prisma
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"
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Ask HN: Is PostgreSQL better than MySQL?
Gh-ost is the new hotness. Simple to use and lots of great features: https://github.com/github/gh-ost
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My Green/blue AWS db deployment strategy for avoiding data loss due to table locks
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
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Changing column from longtext to mediumtext taking over 2 hours
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
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Ask HN: Do you use foreign Keys in Relational Databases
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...
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Migrating a production database without any downtime
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.
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How do you handle RDS schema migrations?
GitHub gh-ost
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Changing Tires at 100mph: A Guide to Zero Downtime Migrations
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