Re: WIP: Avoid creation of the free space map for small tables

On Wed, Jan 30, 2019 at 4:33 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Tue, Jan 29, 2019 at 8:12 PM John Naylor <john.naylor@2ndquadrant.com> wrote:
> >
> > On Tue, Jan 29, 2019 at 11:56 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > > You can find this change in attached patch.  Then, I ran the make
> > > check in src/bin/pgbench multiple times using test_conc_insert.sh.
> > > You can vary the number of times the test should run, if you are not
> > > able to reproduce it with this.
> > >
> > > The attached patch (clear_local_map_if_exists_1.patch) atop the main
> > > patch fixes the issue for me.  Kindly verify the same.
> >
> > I got one failure in 50 runs. With the new patch, I didn't get any
> > failures in 300 runs.
> >
>
> Thanks for verification.  I have included it in the attached patch and
> I have also modified the page.sql test to have enough number of pages
> in relation so that FSM will get created irrespective of alignment
> boundaries.  Masahiko San, can you verify if this now works for you?
>

Thank you for updating the patch!

The modified page.sql test could fail if the block size is more than
8kB? We can ensure the number of pages are more than 4 by checking it
and adding more data if no enough but I'm really not sure we should
care the bigger-block size cases. However maybe it's good to check the
number of pages after insertion so that we can break down the issue in
case the test failed again.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center