Enhancing Performance and Security with Strategic Database Migration
Challenge
Modernising Legacy Systems and Ensuring Performance
In 2020, a major player in the customer-facing services industry presented PMC with a significant challenge: to upgrade their legacy applications and database servers. This ambitious project consisted of multiple dependencies but was primarily aimed at modernising their systems and enhancing overall performance. The task of moving from an outdated database system to a modern version while minimising downtime was complex and critical for the company to maintain seamless operations.
Key challenges included:
- Upgrade Path: The main databases were crucial for the company’s key business functions, requiring minimal downtime during migration. The outdated database system, unsupported for several years, posed significant security risks. With no direct upgrade path to the latest version, a two-step approach was necessary: first migrating to an intermediate version, and then to the latest one.
- Database Size: The primary database, being quite large, necessitated a strategy to minimise downtime.
Approach
Strategic Planning and Risk Mitigation
PMC has supported this forward-thinking company for many years with its portfolio of services, including development, legacy application support, and, since 2018, database management. The relationship stemmed from their quest for a cost-effective database administration (DBA) solution without compromising quality, a need that PMC's capabilities spread across their UK and India offices aptly addressed.
PMC built out a roadmap for the upgrade in five phases covering discovery, design, build, migration, and optimisation. Several risks were identified and mitigated through strategic planning and execution:
- Replication and Compatibility: Ensuring database replication and maintaining backward compatibility to stabilise performance during the upgrade.
- Security Enhancements: Implementing robust security measures such as Windows Integrated Authentication using Kerberos.
- Performance Monitoring: Establishing performance baselines and enabling Query Store to monitor and maintain performance stability.
- Code Upgrades: Updating SQL codes to address deprecated syntax incompatible with the latest database version.
- Minimising Application Changes: Using client aliases to reduce the need for application code changes during the migration window.
Solution
Seamless Migration and Modernisation
PMC's DBA team seamlessly integrated into the business’s operations, augmenting their in-house capability and providing around-the-clock 24/7 support, including backup, recovery, and disaster scenario tests as part of their services.
PMC used differential database backup, initially taking a full database backup and then a final differential backup on the go-live date to reduce downtime and associated risks. Post-migration, PMC leveraged the Query Store feature to identify and resolve query regressions caused by Query Optimiser changes. This methodology, crucial for maintaining performance stability, was also applied during the application load-testing phase.
During the go-live migration, PMC’s support channels were available to address any post-implementation issues promptly, ensuring a smooth transition. Additionally, a comprehensive migration run book was created, detailing all steps and approaches taken, and shared with the company's stakeholders for transparency and future reference.g critical initiatives such as implementing advanced search and merchandising tools across Signet’s websites in record time. This included enabling warranties to be seamlessly available online, a feature previously exclusive to physical stores. PMC also spearheaded the development and implementation of a Pick, Pack, and Dispatch (PPD) solution as part of Signet’s broader digital transformation efforts.
Outcome
Minimal Downtime and Enhanced System Resilience
The main success criteria for this monumental project were clear - it had to be executed flawlessly, with minimal downtime. PMC, through meticulous planning and execution, surpassed these expectations.
- Minimal Downtime: The project was executed with minimal disruption to the company’s operations.
- Improved System Resilience: Post-upgrade, the frequent tickets logged for performance issues dwindled to none, showcasing a significant improvement in system resilience.
- Commitment to Excellence: This successful migration project underscores PMC's commitment to delivering exceptional service levels. Over the last four years, PMC has consistently achieved a remarkable 99.9% service level agreement (SLA) for this client, reflecting the trust and satisfaction they place in PMC's service delivery.
Navigating the intricate technicalities of this database migration project has been both challenging and immensely rewarding for PMC. We’re proud to have successfully delivered on our promises, meeting critical deadlines while ensuring minimal disruption to our customer’s operations. It’s a testament to the expertise and dedication of our team, as well as the trust our customer placed in us.
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