Legacy Codebase Bugfixing
Analysis and resolution of a critical search function bug in a legacy shop software.
About the Project
A customer operated legacy shop software that was customized for various end customers. Reports of poor search results with unpredictable behavior accumulated: A search for "KB-281" (internal designations like KB-281-001, KB-281-002 etc.) found nothing, while "KB-282-001" was found. The behavior was incomprehensible to users.
Analysis
Thorough code analysis revealed a fundamental problem in the search algorithm: The application used a self-implemented fuzzy search based on MySQL. The algorithm generated fuzzy terms at runtime based on configurable parameters in the admin portal – which is why adjustments sometimes delivered better results for some terms but worsened others.
Root Cause
The core problem: User input was never searched directly as a keyword. The fuzzy algorithm returned a list of terms but did not reliably include the split keywords from the original query.
The Solution
The developed solution was a hybrid approach: The fuzzy terms continued to be used, supplemented by sanitized and split keywords from the user input. This enabled both keyword-based and fuzzy searches – making the search significantly more robust and reliable.
Highlights
- Root cause analysis in complex legacy codebase
- Identification of a subtle but critical bug
- Hybrid solution without complete rewrite
- Secure implementation with input sanitization
Challenges
Understanding the complex, self-implemented fuzzy search logic. Balance between fix and regression avoidance.
Results
Reliable search results for all product designations. Resolution of long-standing customer complaints.
Interested?
Are you interested in a similar project or want to learn more? Get in touch – we look forward to hearing from you!
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