Index bloat and B-tree page merge, part 3

session summary

The group refined a minimal B-tree merge: move tuples from a very sparse leaf page into its right sibling, then reuse existing page-deletion machinery. They inspected page layouts, asked an agent to implement the change inside vacuum, and built a sparse index. After removing an assertion, one page was successfully emptied without a crash. However, regression and foreign-key tests failed, and concurrent scans were not tested, so the result remained a potentially corrupt prototype rather than a valid patch.

timecodes

1. 00:30 Recap: turning sparse leaf pages into deletable pages
2. 03:30 Comparing candidate leaf-page merge layouts
3. 12:00 Applying Lehman-Yao page-merge ideas to Postgres
4. 24:00 Minimal plan: move tuples, then reuse page deletion
5. 34:00 Inspecting leaf pages before and after vacuum
6. 49:30 Prompting the first vacuum-integrated implementation
7. 01:16:30 Building a sparse-index test for the prototype
8. 01:27:00 One merge succeeds, but regression tests fail