Recently, compliance requirements have increasingly started to affect technical work. There are frequent requests to implement compliance-related features or to complete compliance assessments. From my perspective, these requirements mainly focus on user data governance, including standardized access control and gradually giving users more control over their own data.
At the same time, organizational and personnel changes are also having a noticeable impact on the system. For example, when a business domain is transferred to another department, shared resources such as databases become a point of contention. Cost allocation then becomes a practical issue. Even within the same company, internal accounting mechanisms make these discussions unavoidable, and disputes over resource usage are quite common.
In addition, shared systems introduce another challenge. When other teams need to modify common database structures or interfaces, it often requires additional effort from our side. These changes usually come with urgency, but without corresponding ownership or recognition, which makes coordination more difficult.
Regarding the PHP gateway migration mentioned in my previous report, the work had already been ongoing for one to two months. Although the new service was implemented early, the process of switching traffic exposed many hidden issues.
In the test environment, the service appeared stable for a long time. However, once traffic was switched in production, problems began to surface. Some interfaces failed unexpectedly, while others returned errors. In such cases, the only safe approach was to roll back traffic immediately and investigate the issue.
This process repeated multiple times. Sometimes, issues were only reported several days after a traffic switch, which significantly extended the migration timeline. Although there was pressure to complete the migration quickly, the actual situation was more complex.
Even though I was not responsible for all the subsequent implementation and maintenance, it became clear that fully replacing an existing service is a gradual process. Without sufficient documentation and test coverage, it is difficult to ensure that the new implementation is completely equivalent to the old one. Hidden logic often only becomes visible under real production traffic.
Despite the iterative and sometimes frustrating process, the migration was finally completed this week, and all traffic has been successfully moved to the new service. This effectively marks the end of the old PHP gateway.
After taking over the main backend systems for nearly half a year, my perspective has also changed. At the beginning, I felt that the existing systems were highly complex and difficult to understand. Over time, I started to see that many parts of the system have imperfections, and in some cases, serious design issues.
For example, Redis is used as a primary data store in some services, without proper expiration strategies, while the stored data is critical and cannot be lost. There are also legacy services with no documentation and no active maintainers, making them difficult to analyze or modify. Some of these services are rarely used, but occasionally become critical when unexpected requests appear.
In addition, there are security concerns that need to be addressed. Some API accounts have overly broad permissions, but their actual usage is unclear. These kinds of issues are common in daily work and are difficult to fully eliminate.
Overall, this week reinforced my understanding that maintaining and evolving real-world systems involves not only technical challenges, but also organizational complexity, legacy constraints, and incomplete information.