While doing an upgrade from 1.6.? to MOODLE_18_STABLE for a client, I had to remove a few calls to rebuild_course_cache() which were interfering with the upgrade process:
Then, I compared the database schemas of a fresh MOODLE_18_STABLE install with the upgraded database and fixed the following discrepancies:
- mod-exercise_add_late_field.patch: add the 'late' field which was missing from exercise_submissions
- mod-scorm_version_field.patch: add the 'version' field which was missing from scorm
- question-type-rqp_missing_servers_table.patch: adds the missing 'question_rqp_servers' table
These patches are against:
except for the rqp question type one since it's no longer part of the core. I have committed a fix for that one in contrib HEAD.
After making these changes, I was able to upgrade this install of Moodle 1.6 to 1.8 without any errors or differences in the schema.