Background The Skinny
Performing schema changes often requires extended downtime for
applications. This is due to MySQL needing to rebuild tables for
common schema change operations. Tools like
pt-online-schema-change have been written to try to
overcome the downtime associated with schema changes, however
they are complex and put a high load on the database. Amazon’s
Aurora improves some schema changes operations, but still
requires a table rebuild for common operations like adding a
after, or simply
to add a column with a
default value. Rebuilding a
table with millions of rows can take hours and prevent writes to
that table the entire time.
How Can Tungsten Clustering Keep Applications Running? How Does It All Work?