Case Study · Aviation / Database & Compliance
Zero downtime, zero lost bookings: a national airline’s core database, upgraded in flight
A 6 TB Oracle database, moved from 11g to 12c with no outage and not a single lost booking — the zero-downtime upgrade, delivered on Oracle GoldenGate, that made Khwarizm the airline’s sole choice for its GDPR compliance programme.
Some of Khwarizm’s deepest relationships go back to its earliest days — and few run deeper than the one with a leading national airline. It began with a problem most database teams quietly dread: upgrade a 6 TB production database from Oracle 11g to 12c — without downtime. For an airline, that constraint is not a preference. If the database stops, so does booking, and every minute of outage risks lost or delayed reservations and frequent-flyer transactions. Khwarizm found a way to change the engine while the aircraft stayed in the air.
When downtime is not an option
A major database version upgrade normally means an outage — take the system offline, upgrade, test, bring it back. For most businesses that is an inconvenience to be scheduled for a quiet weekend. For an airline whose booking and frequent-flyer systems run around the clock, there is no quiet weekend, and no acceptable window in which reservations simply stop. The upgrade had to happen with the lights on.
Upgrading the engine mid-flight
Khwarizm’s approach turned a risky big-bang cutover into a controlled, reversible transition. Using Oracle GoldenGate, the team stood up the new 12c environment alongside the live 11g system and kept the two continuously synchronized by real-time replication. Bookings kept flowing to the running system throughout, while the upgraded database was built and validated in parallel — and when everything was proven, the switch-over was made cleanly, with the replication safety-net still in place.
The result was exactly what the airline needed and had been told was hard to promise: zero downtime, and zero booking loss or delay. The frequent-flyer systems never skipped a beat. The 6 TB upgrade, running on Oracle Database Appliance, happened without a single passenger ever knowing it had.
We were told a 6 TB upgrade without downtime couldn’t be guaranteed. Khwarizm delivered it — our bookings never stopped, and we didn’t lose a single reservation.
Trust, earned the hard way
Pulling off a zero-downtime upgrade on a system that cannot fail does something no proposal ever can: it removes doubt. When the airline faced its next critical, non-negotiable initiative — a mandatory GDPR compliance programme — it did not run a competitive tender. It considered only one partner. Khwarizm had already proven it could be trusted with the systems the business runs on.
From migration to compliance
Khwarizm approached the programme from the data outward. A dedicated security expert was assigned to review the GDPR requirements specifically against the database — making sure the airline’s obligations were met where the personal data actually lived, not merely satisfied on paper.
The resulting work reached across the whole database estate. Khwarizm handled database patching and upgrades and security-pack setup, and layered in defense-in-depth data protection: Transparent Data Encryption to protect personal data at rest; Oracle Database Vault to enforce separation of duties and stop even highly privileged administrators from reaching that data; and Oracle Audit Vault and Database Firewall (AVDF) to consolidate audit trails and monitor database activity in real time, so unauthorized or suspicious access could be detected and blocked. Together they meant the airline could prove exactly who touched personal data and when — and that the data was encrypted, access-controlled, and watched. Compliance stopped being a paperwork exercise and became a property of the platform itself.
Going beyond the brief
This is the kind of work that runs in Khwarizm’s veins — and it showed. Rather than tick off a fixed scope, the team went looking. It helped the airline uncover further areas exposed to GDPR that had not been on anyone’s list, and identified underlying risks in the database before they could become incidents. The airline came away not just compliant against a checklist, but genuinely better protected — with a clearer view of where its personal data lived and where it was vulnerable.
The results
What began as one impossible-sounding upgrade became a lasting partnership. By keeping an airline’s bookings flowing through a change that could have grounded them, and then hardening the very data those bookings depend on, Khwarizm turned a single high-stakes project into a relationship the airline returns to whenever the systems it cannot afford to get wrong are on the line.