In this blog post we’ll discuss pt-online-schema-change, and how to correctly use it.
Always use pt-osc?
Altering large tables can be still a problematic DBA task, even now after we’ve improved Online DDL features in MySQL 5.6 and 5.7. Some ALTER types are still not online, or sometimes just too expensive to execute on busy production master.
So in some cases, we may want to apply an
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