Worked on enhancing documentation for the Altinity/ClickHouse repository, focusing on clarifying MergeTree TTL and drop parts behavior. Improved the accuracy and maintainability of technical guides by updating Markdown files to reflect the latest code references and actual system behavior. Added detailed explanations for the ttl_only_drop_parts semantics and documented the cache_populated_by_fetch setting, ensuring that onboarding materials are more accessible for new contributors. Emphasized cross-referencing and example updates to reduce confusion around TTL-based data lifecycle and caching. The work leveraged strong documentation skills and a deep understanding of ClickHouse internals, resulting in safer deployments and more effective performance tuning.