Hi,
Liquibase runs the changeset in the order you make in the changelog, from the documentation it says:
As Liquibase executes the databaseChangeLog, it reads the changeSets in order and, for each one, checks the “databasechangelog” table to see if the combination of id/author/filepath has been run. If it has been run, the changeSet will be skipped unless there is a true “runAlways” tag. After all the changes in the changeSet are run, Liquibase will insert a new row with the id/author/filepath along with an MD5Sum of the changeSet (see below) in the “databasechangelog”.
The ordering is the user's responsibility, the paridgm isn't to check to see if there was a new add to the changelog. The liquibase enterprise product (aka Datical) does sorta verify ordering but it has another commit order paradigm it follows.
HTH,
Ronak