Looks similar to issue that I had when I was trying to use both database migration AND DataSource based database creation. These two overlap in functionality and may clash with errors. Therefore, either do
grails.plugin.databasemigration.dropOnStart = true
grails.plugin.databasemigration.updateOnStart = true
with dbCreate = ‘validate’ (or empty) in DataSource.groovy (under appropriate environment) OR do
grails.plugin.databasemigration.dropOnStart = false
grails.plugin.databasemigration.updateOnStart = false
with dbCreate = ‘create-drop’ in DataSource.groovy.
For me the latter has worked better with both h2 and MySQL databases.
/Michael
PS: You may want to debug this under the development environment rather than diving straight into performance.