Re: Add contrib/pg_logicalsnapinspect

On Wed, Mar 5, 2025 at 4:05 AM Bertrand Drouvot
<bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
>
> Hi,
>
> On Wed, Mar 05, 2025 at 02:42:15PM +0530, Amit Kapila wrote:
> > On Wed, Mar 5, 2025 at 12:47 PM Bertrand Drouvot
> > <bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
> > >
> > > Agree, PFA a patch doing so.
> > >
> >
> > It would be better if you could add a few comments atop the
> > permutation line to explain the working of the test.
>
> yeah makes sense. Done in the attached, and bonus point I realized that the
> test could be simplified (so, removing useless steps in passing).
>

Thank you for the patch.

The new simplified test case can be pretty-formatted as:

init
begin
savepoint
truncate
checkpoint-1
get_changes-1
commit
checkpoint-2
get_changes-2
info_catchange check
info_committed check
meta check

IIUC if another checkpoint happens between get_change-2 and the
subsequent checks, the first snapshot would be removed during the
checkpoint, resulting in a test failure. I think we could check the
snapshot files while one transaction keeps open. The more simplified
test case would be:

init
begin
savepoint
insert(cat-change)
begin
insert(cat-change)
commit
checkpoint
get_changes
info_catchange check
info_committed check
meta check
commit

In this test case, we would have at least one serialized snapshot that
has both cat-changes and committed txns. What do you think?

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com