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

On Wed, Mar 6, 2019 at 5:19 PM John Naylor <john(dot)naylor(at)2ndquadrant(dot)com> wrote:
>
> On Fri, Jan 25, 2019 at 9:50 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > Once we agree on the code, we need to test below scenarios:
> > (a) upgrade from all supported versions to the latest version
> > (b) upgrade standby with and without using rsync.
>
> Although the code hasn't been reviewed yet, I went ahead and tested
> (a) on v21 of the pg_upgrade patch [1]. To do this I dumped out a 9.4
> instance with the regression database and restored it to all supported
> versions. To make it work with pg_upgrade, I first had to drop tables
> with oids, drop functions referring to C libraries, and drop the
> later-removed '=>' operator. Then I pg_upgrade'd in copy mode from all
> versions to HEAD with the patch applied. pg_upgrade worked without
> error, and the following query returned 0 bytes on all the new
> clusters:
>
> select sum(pg_relation_size(oid, 'fsm')) as total_fsm_size
> from pg_class where relkind in ('r', 't')
> and pg_relation_size(oid, 'main') <= 4 * 8192;
>
> The complementary query (> 4 * 8192) returned the same number of bytes
> as in the original 9.4 instance.
>

Thanks, the tests done by you are quite useful. I have given a few
comments as a response to your previous email.

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