Re: pgsql: Avoid creation of the free space map for small heap relations, t

On Thu, Feb 28, 2019 at 7:45 AM John Naylor <john(dot)naylor(at)2ndquadrant(dot)com> wrote:
>
> On Thu, Feb 28, 2019 at 7:24 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > > The flaw in my thinking was treating extension too similarly too
> > > finding an existing block. With your patch clearing the local map in
> > > the correct place, it seems the call at hio.c:682 is now superfluous?
> >
> > What if get some valid block from the first call to
> > GetPageWithFreeSpace via local map which has required space? I think
> > in that case we will need the call at hio.c:682. Am I missing
> > something?
>
> Are you referring to the call at line 393? Then the map will be
> cleared on line 507 before we return that buffer.
>

That's correct, I haven't looked at line number very carefully and
assumed that you are saying to remove the call at 507. I also think
that the call at line 682 doesn't seem to be required, but I would
prefer to keep it for the sake of consistency in this function and
safety purpose. However, I think we should add a comment on the lines
suggested by you. I will send the patch after making these
modifications.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com