Re: Xmax precedes relation freeze threshold errors

On Tue, Jun 14, 2022 at 8:48 PM Álvaro Herrera <alvherre@alvh.no-ip.org> wrote:

> Oh, that definitely sounds like a bug in amcheck then.  Please post the
> output of
>  select * from heap_page_items(get_raw_page('the table', the_page));
> for some of these pages, preferrably just around the time the errors for
> these pages are shown; maybe someone can figure out which tuples cause
> these errors and how to fix amcheck.  It might be difficult to catch
> tuples 'in the act' though.

I've switched to another table with less update traffic and was able
to catch the following:

(verify_heapam  before)
blkno | offnum | attnum |                               msg
-------+--------+--------+-----------------------------------------------------------------
 20365 |      8 |        | xmax 1965224948 precedes relation freeze
threshold 1:1914858032
 20365 |     12 |        | xmin 1965224948 precedes relation freeze
threshold 1:1914858032
(2 rows)

(heap_page_items dump) - https://dpaste.org/fWzEj/raw

(verify_heapam  after)
 blkno | offnum | attnum |                               msg
-------+--------+--------+-----------------------------------------------------------------
20365 |     12 |        | xmax 1965224955 precedes relation freeze
threshold 1:1914858032
20365 |     15 |        | xmin 1965224955 precedes relation freeze
threshold 1:1914858032
(2 rows)

If this is not enough, I can try to catch even more matching before/after pairs.

Best regards,
Sergey Aleynikov