Worked on improving the reliability of tag-based filtering in the VictoriaMetrics/VictoriaMetrics repository by addressing a bug in the TagFilter sorting logic. Focused on correcting the Less method within the tagFilter struct to ensure accurate assignment of isComposite, which resolved issues with incorrect sorting and potential performance degradation. The solution involved refactoring Go code and introducing targeted unit tests to validate the new behavior, specifically through the addition of TestTagFilterLess. This work emphasized careful bug fixing, code refactoring, and comprehensive testing, contributing to more accurate query results and enhanced performance in the VictoriaMetrics time series database.