In our use case I noticed a serious slowdown in schema migration after upgrading from 4.3 => 5.4.

For this I created a fix, that reads the tables in DatabaseInformationImpl for the whole namespace in one go, instead of one at a time. See attached patch too.

Schema migration with 5.4.10-final => 2 minutes 38 seconds
Schema migration with 5.4.11-final with cache: 1 minute 20 seconds

In our test case this concerns 559 classes that map to about 2400 tables.