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Plan for migrating from Oracle to PostgreSQL:

1. Scope the problem. Get a count of workflow and workflow_archive

• On workflow-server-rails
  1. ActiveRecord::Base.connection.query('SELECT count(*) from workflow_archive')
  2. ActiveRecord::Base.connection.query('SELECT count(*) from workflow')
• On workflow-archiver-job
  1. DB = Dor::WorkflowArchiver.new.conn
  2. DB.fetch('SELECT count(*) from workflow').first[:'count(*)'] (currently 572785)
  3. DB.fetch('SELECT count(*) from workflow_archive').first[:'count(*)'] (currently 126,069,766)

1. Disable the workflow-archiver-job (remove from crontab) so that no new rows get added to workflow_archive.
2. Export workflow_archive to a CSV?
3. Import the CSV as workflows
4. Export workflow to a CSV.
5. Import the CSV, while calculating the current version for each row.