Re: Vacuum statistics

Hi Andrey, thank you for taking a look and for the review!

On 13 Mar 2026, at 18:04, Alena Rybakina <lena.ribackina@yandex.ru> wrote:

I've decided to take a look into v31.

Overall idea of tracking VM dynamics seems good to me.

Thank you!

But the column naming for rev_all_visible_pages and rev_all_frozen_pages
seems strange to me. I've skimmed the thread but could not figure out what
"rev_" stands for. Revisions? Revolutions? Reviews?

We meant "revision", but after looking at our documentation I realized
the confusion - the term is not explained there.

I've renamed them to visible_pages_vm_cleared and frozen_pages_vm_cleared.

Does this naming make more sense?

Is there a reason why you break "SELECT * FROM pg_stat_all_tables" for
an existing software? IMO even if we want these columns in this exact view
- they ought to be appended to the end of the column list.

No reason, I fixed this. Thanks for pointing it out.

Some nits about the code.

my $interval   = 0.015;
sleep($interval); <--- sleep takes integer AFAIK?

Maybe just use poll_query_until()?

$start_time seems unused.

I don't think src/test/recovery/t/ is good for the test. It has nothing to
do with recovery. Maybe somewhere in src/test/modules?

I reconsidered the test and moved it to the regression tests (at the end of vacuum.sql). 

With pg_stat_force_next_flush() they seem stable enough without using waiting functions.

This change is not needed at all:
- proargtypes => 'oid8 int8', prosrc => 'hashoid8extended' },
+ proargtypes => 'oid8 int8', prosrc => 'hashoid8extended' },

s/'statistics: number of times the all-visible pages in the visibility map
was removed for pages of table'/'statistics: number of times the all-visible
pages in the visibility map were cleared for pages of this table'/g

I would appreciate some braces in
if (map[mapByte] >> mapOffset & flags & VISIBILITYMAP_ALL_VISIBLE)
Probably the code is correct, but I write in languages with different parsers
and do not trust in grammar priorities. Is it something like following?
if (map[mapByte] & ((VISIBILITYMAP_ALL_VISIBLE & flags) << mapOffset))
We check (map[mapByte] & mask) in this if statement which is flags << mapOffset btw...

Fixed.

That's all what catches my eye this time. Thank you!

Thank you for the review!

-----------
Best regards,
Alena Rybakina