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

On Thu, Jan 31, 2019 at 6:41 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Wed, Jan 30, 2019 at 10:41 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > The modified page.sql test could fail if the block size is more than
> > 8kB?
>
> That's right, but I don't think current regression tests will work for
> block size greater than 8KB. I have tried with 16 and 32 as block
> size, there were few failures on the head itself.
>
> > 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.
> >
>
> Yeah, I am not sure either. I think as this is an existing test, we
> should not try to change it too much. However, if both you and John
> feel it is better to change, we can go with that.

I have an idea -- instead of adding a bunch of records and hoping that
the relation size and free space is consistent across platforms, how
about we revert to the original test input, and add a BRIN index? That
should have a FSM even with one record.

--
John Naylor https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services