pgsql: Properly determine length for on-disk TOAST values

Properly determine length for on-disk TOAST values

In detoast_attr_slice, VARSIZE_ANY was used to compute compressed length
of on-disk TOAST values. That's incorrect, because the varlena value may
be just a TOAST pointer, producing either bogus value or crashing.

This is likely why the code was crashing on big-endian machines before
540f31680913 replaced the VARSIZE with VARSIZE_ANY, which however only
masked the issue.

Reported-by: Rushabh Lathia
Discussion: https://postgr.es/m/CAL-OGkthU9Gs7TZchf5OWaL-Gsi=hXqufTxKv9qpNG73d5na_g@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2dc08bd6179d8cf480c93701010c19ad7a9891d8

Modified Files
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src/backend/access/common/detoast.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)