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"...
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.