This article discusses how to salvage a
crashed 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
as RENAME TABLE
and DROP TRIGGER
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 pt-online-schema-change
. In
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 …
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