Question

I am running grails 1.3.7 and using the grails database migration plugin version database-migration-1.0

The problem I have is I have a migration change set. That is pulling blobs out of a table and writing them to disk. When running through this migration though I am running out of heap space. I was thinking I would need to flush and clear the session to free up some space however I am having difficulty getting access to the session from within the migration. BTW The reason it’s in a migration is we are moving away from storing files in oracle and putting them on disk

I have tried

SessionFactoryUtils.getSession(sessionFactory, true)

I have also tried

SecurityRequestHolder.request.getSession(false)   //request in null -> not surprising

---

changeSet(author: "userone", id: "saveFilesToDisk-1") {
    grailsChange{
        change{
            def fileIds = sql.rows("""SELECT id FROM erp_file""")
            for (row in fileIds) {
                def erpFile = ErpFile.get(row.id)
                erpFile.writeToDisk()
                session.flush()
                session.clear()
                propertyInstanceMap.get().clear()
            }
            ConfigurationHolder.config.erp.ErpFile.persistenceMode = previousMode
        }
    }
}

Any help would be greatly appreciated.

Answer 1

The application context will be automatically available in your migration as ctx. You can get the session like this:

def session = ctx.sessionFactory.currentSession