On Mon, 2021-04-26 at 21:55 +0000, PG Doc comments form wrote: > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/12/storage-vm.html > Description: > > Currently the documentation lists the line below; > > `Each heap relation has a Visibility Map (VM) to keep track of which pages > contain only tuples that are known to be visible to all active > transactions;` > > Should it instead read like; > > `Each heap relation has a Visibility Map (VM) to keep track of only those > pages that contain tuples known to be visible to all active transactions;` > > After reading through the documentation and reading the first line, I first > thought that VM only kept track of pages that only had visible tuples. > Instead my understanding is that it shows which pages have any visible > tuples in them.
I think that the wording of the documentation is more correct. The VM also tracks the pages that are not all-visible. They have the corresponding bit set to 0. Yours, Laurenz Albe
