GitHub Enterprise Server upgrade: database schema inconsistency after migration failure

Direct Answer

No. When a GitHub Enterprise Server upgrade fails during the database migration phase, the appliance does not continue serving normal application traffic. The code is updated to the new version, but the database schema remains at the previous version, so the application typically rejects requests and displays a maintenance or error page until the schema is brought into a consistent state.

Likely Explanation vs. Confirmed Behavior

Confirmed: GHES upgrades run database migrations before declaring success. If a migration fails, the upgrade tool logs the failure to /var/log/enterprise-server/upgrade.log and does not automatically revert the schema. The result is a version mismatch between application code and database schema.

Likely but version-dependent: The exact user-facing behavior (hard error page vs. limited read-only access) and the availability of automatic rollback hooks vary by release. Older GHES versions may not include rollback hooks at all. Treat any specific rollback procedure as version-specific and verify it against the documentation for your exact target release before proceeding.

Verifying Schema Consistency Before Manual Rollback

Before attempting a manual rollback, confirm whether the schema is at the expected target version. The internal database records applied migrations in the schema_migrations table.

1. SSH into the GHES appliance.
2. Open the database console. The command is typically sudo /usr/local/share/enterprise/ghe-dbconsole, but confirm the exact path for your release.
3. Query the highest applied migration:
   SELECT MAX(version) FROM schema_migrations;
4. Identify the expected schema version for the target GHES release. This is usually listed in the upgrade package manifest or the official release notes. The exact cache path (for example, under /var/cache/enterprise-upgrade/) varies by version and should be verified locally.
5. Compare the two values. If they match, the schema is consistent with the target release and a manual rollback may be considered. If they differ, the migration did not complete; retry the upgrade or restore from a pre-upgrade backup rather than rolling back manually.

Safety and Next Steps

Always take a fresh backup of the GHES database before any manual schema inspection or rollback. Manual rollback procedures are not universal across GHES releases; attempting one without the correct version-specific hooks can leave the database in an unusable state. If the query above returns a mismatch and no safe rollback path exists for your version, restoring the appliance from the pre-upgrade backup is the conservative recovery path.

Missing Diagnostic Detail

Which exact GHES version were you upgrading from and to? Rollback hooks, database client paths, and the location of the expected schema version file differ across major GHES releases, so the version pair determines whether a manual rollback is even supported.