In my last post, “A closer look at the MySQL ibdata1 disk space
issue and big tables,” I looked at the growing ibdata1
problem under the perspective of having big tables residing
inside the so-called shared tablespace. In the particular case
that motivated that post, we had a customer running out of disk
space in his server who was looking for a way to make the ibdata1
file shrink. As you may know, that file (or, as explained
there, the set of ibdata files composing the shared tablespace)
stores all InnoDB tables created when innodb_file_per_table is
disabled, but also other InnoDB structures, such as undo
logs and data dictionary.
For example, when you run a transaction involving InnoDB
tables, MySQL will first write all the changes it triggers in an
undo log, for the case you later decide to …
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