About

Backend engineer at Productive. I work on the sales side of the application with the CRM team and on app-wide performance optimizations with the Platform team. Ruby on Rails & MySQL.

MSc in Computer Science from FER, 2026. Occasional contributor to ruby-lsp, ruby-lsp-rails and rubocop-rspec.

Writing

MySQL can't merge sorted index ranges (and the UNION ALL fix)

2026-07-23

An IN filter with one value is fast. Add a second value and MySQL scans the whole table. Why it happens, and the UNION ALL fix.