Liquibase is really only for schema/structure management, not data
replication - I'm not sure if that is what you are asking or not.
If you are worried about things like "adding a column to a
table causes the table to be locked for a long time" then you are
correct to be worried - this is definitely something to be aware of
when altering a schema, no matter how you do it. Liquibase doesn't
have any magic in this regard. One thing you can always do is use
Liquibase with the 'generateSQL' option to preview what will
actually be run. I did a quick Googling of pt-online-schema-change and
Liquibase does not do anything like what that tool is trying to do -
the SQL generated is more along the lines of "ALTER TABLE
tablename..." rather than what that tool seems to be doing.
I don't know a whole lot about database replication in MySQL at
all, but basically you would need to follow the same steps as if you
were doing schema changes 'manually' using SQL scripts, except
that Liquibase is the one generating the SQL rather than having to
custom-create it for each database.
Steve Donie
Principal Software Engineer
Datical, Inc. http://www.datical.com/