> For the complete documentation index, see [llms.txt](https://til.notdu.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://til.notdu.com/database/intro-to-database-systems/tree-indexes-i/merge-threshold.md).

# Merge threshold

Some DBMSs do not always merge nodes when it is half full.

Delaying a merge operation may reduce the amount of reorganization.

It may also be better to just let underflows to exist and then periodically rebuild entire tree.