This article discusses how to salvage a
pt-online-schema-change by leveraging
pt-archiver and executing queries to ensure that the
data gets accurately migrated. I will show you how to
continue the data copy process, and how to safely close out the
pt-online-schema-change via manual operations such
RENAME TABLE and
commands. The normal process to recover from a crashed
pt-online-schema-change is to drop the triggers on
your original table and drop the new table created by the script.
Then you would restart
this case, this wasn’t possible.
A customer recently needed to add a primary key column to a very busy table (with around 200 million rows). The table only had a …[Read more]