> 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/multi-threaded-index-concurrency-control/latch-modes.md).

# Latch modes

Read mode

* Multiple threads can read the same object at the same time.
* A thread can acquire the read latch if another thread has it in read mode.

Write mode

* Only one thread can access the object.
* A thread cannot acquire a write latch if another thread holds the latch in any mode.