Re: Postgresql | Vacuum information

On Wed, Feb 28, 2018 at 11:31 AM, Sohel Tamboli <sohel(dot)tamboli0016(at)gmail(dot)com
> wrote:

> Hi,
>
> I need some information on vacuum in postgresql. I know that "vacuum full"
> recreate full table and releases space to OS. Only "vacuum" clears the dead
> tuples and free the space but does not returns free space to OS, indeed it
> keeps free space as a part of table.
> My question is, after running only "vacuum", how does new data or insert
> is written to the table? I need to know that Does new data gets inserted in
> free space available in between of live tuples or gets inserted at the end
> of table everytime.
>
>
There would be no point to non-full vacuuming if "new data [was] inserted
... at the end of the table everytime"...​

​This logic is also documented:​

​
https://www.postgresql.org/docs/10/static/routine-vacuuming.html#VACUUM-BASICS
​

​"
The space it occupies must then be reclaimed for reuse by new rows, to
avoid unbounded growth of disk space requirements. This is done by running
VACUUM.
​"​

​David J.