B-tree Index Bloat Reduction (Page Merge)

PostgreSQL B-tree indexes often suffer from severe bloat after heavy UPDATE and DELETE workloads because the core engine currently cannot consolidate sparse pages. This project introduces safe, concurrent in-core leaf page merging. By utilizing a two-phase protocol, it consolidates two sparsely populated sibling pages into one without blocking concurrent forward or backward scanners. Key deliverables include the core atomic merge logic, a two-stage flag system to safely route concurrent traversals, atomic WAL logging for crash resilience, VACUUM cleanup integration, and analytical visualization tooling built via pageinspect.