Re: pg_amcheck contrib application

On Fri, Apr 23, 2021 at 2:15 PM Mark Dilger
<mark.dilger@enterprisedb.com> wrote:
> Another difference I should probably mention is that a bunch of unrelated tests are failing with errors like:
>
>     toast value 13465 chunk 0 has size 1995, but expected size 1996
>
> which leads me to suspect your changes to how the size is calculated.

That seems like a pretty reasonable suspicion, but I can't see the problem:

-       expected_size = curchunk < endchunk ? TOAST_MAX_CHUNK_SIZE
-               : VARATT_EXTERNAL_GET_EXTSIZE(ta->toast_pointer) -
(endchunk * TOAST_MAX_CHUNK_SIZE);
+       expected_size = chunk_seq < last_chunk_seq ? TOAST_MAX_CHUNK_SIZE
+               : extsize % TOAST_MAX_CHUNK_SIZE;

What's different?

1. The variables are renamed.

2. It uses a new variable extsize instead of recomputing
VARATT_EXTERNAL_GET_EXTSIZE(ta->toast_pointer), but I think that
should have the same value.

3. I used modulo arithmetic (%) instead of subtracting endchunk *
TOAST_MAX_CHUNK_SIZE.

Is TOAST_MAX_CHUNK_SIZE 1996? How long a value did you insert?

-- 
Robert Haas
EDB: http://www.enterprisedb.com