Re: AW: Vacuum only with 20% old tuples

Zeugswetter Andreas SB wrote:

> > OK,I see. Your idea seems to be close to Vadim's *relink*.
> > However it isn't clear if *relink* has no problem.
> > In my test case on cygwin port ,*relink* doesn't work well.
> > *relink* caused an error if concurrent backends open the
> > *relink*ing table.
>
> All actions involving a rename of a file imho involve exclusive access
> to the table, thus no concurrent access is allowed/possible.
>

Once a table file was opened,it is not closed until the end of the
backend process except due to the shortage of  file descriptors.

Even now,cygwin port has a flaw that we have no guarantee to
recreate a table safely after dropping the table. Unfortunately
we couldn't recreate the same named file until all processes
close the file in cygwin.

Regards.

Hiroshi Inoue