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

On Fri, Feb 22, 2019 at 1:57 AM Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
>
> I think this test is going to break on nonstandard block sizes. While
> we don't promise that all tests work on such installs (particularly
> planner ones),
>

The reason for not pushing much on making the test pass for
nonstandard block sizes is that when I tried existing tests, there
were already some failures. For example, see the failures in the
attached regression diff files (for block_size as 16K and 32K
respectively). I saw those failures during the previous
investigation, the situation on HEAD might or might not be exactly the
same. Whereas I see the value in trying to make sure that tests pass
for nonstandard block sizes, but that doesn't seem to be followed for
all the tests.

> it seems fairly easy to cope with this one -- just use a
> record size expressed as a fraction of current_setting('block_size').
> So instead of "1024" you'd write current_setting('block_size') / 8.
> And then display the relation size in terms of pages, not bytes, so
> divide pg_relation_size by block size.
>

The idea sounds good. John, would you like to give it a try?

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