Vitess introduces a new way to run schema migrations: non-blocking, asynchronous, scheduled online DDL. With online DDL Vitess simplifies the schema migration process by taking ownership of the operational overhead, and providing the user a simple, familiar interface: the standard ALTER TABLE statement. Let’s first give some background and explain why schema migrations are such an issue in the databases world, and then dive into implementation details The relational model and the operational overhead # The relational model is one of the longest surviving models in the software world, introduced decades ago and widely used until today.
Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.
Some big news out from Microsoft about their acquisition of GitHub for $7.5 billion. GitHub hosts many projects, including from the MySQL ecosystem, but maybe more interesting is that their DBA team is awesome, give great talks, and are generally prolific writers. Some of the cool tools the MySQL world has gotten thanks to the excellent team include (but are not limited to): ccql, gh-ost for triggerless online schema migrations, and Orchestrator which is a GUI-based High Availability and …[Read more]
In this post I will show you how to leverage Github’s gh-ost hooks for greatly improving visibility of ongoing schema changes for your organization.
One of the potential uses of gh-ost hooks is to send status updates. I will present you with some examples of how to do that via email and Slack.
What are gh-ost hooks?
gh-ost has built-in support for hooks, i.e. external scripts with predefined names, that will be called by gh-ost at certain points of a schema change operation.
The complete list is available here, but the most useful gh-ost hooks for me are:
- called at the start of a schema change operation
- ran …
In this blog post, I will run a gh-ost benchmark against the performance of pt-online-schema-change.
When gh-ost came out, I was very excited. As MySQL ROW replication became commonplace, you could use it to track changes instead of triggers. This practice is cleaner and safer compared to Percona Toolkit’s pt-online-schema-change. Since gh-ost doesn’t need triggers, I assumed it would generate lower overhead and work faster. I frequently called it “pt-online-schema-change on steroids” in my talks. …[Read more]