> On Mar 17, 2021, at 9:00 PM, Mark Dilger <mark.dilger@enterprisedb.com> wrote:
>
> Of the toast pointer fields:
>
> int32 va_rawsize; /* Original data size (includes header) */
> int32 va_extsize; /* External saved size (doesn't) */
> Oid va_valueid; /* Unique ID of value within TOAST table */
> Oid va_toastrelid; /* RelID of TOAST table containing it */
>
> all seem worth getting as part of any toast error message, even if these fields themselves are not corrupt. It just
makesit easier to understand the context of the error you're looking at. At first I tried putting these into each
message,but it is very wordy to say things like "toast pointer with rawsize %u and extsize %u pointing at relation with
oid%u" and such. It made more sense to just add these four fields to the verify_heapam tuple format. That saves
puttingthem in the message text itself, and has the benefit that you could filter the rows coming from verify_heapam()
forones where valueid is or is not null, for example. This changes the external interface of verify_heapam, but I
didn'tbother with a amcheck--1.3--1.4.sql because amcheck--1.2--1.3. sql was added as part of the v14 development work
andhas not yet been released. My assumption is that I can just change it, rather than making a new upgrade file.
>
> These patches fix the visibility rules and add extra toast checking.
These new patches address the same issues as v9 (which was never committed), and v10 (which was never even posted to
thislist), with some changes.
Rather than print out all four toast pointer fields for each toast failure, va_rawsize, va_extsize, and va_toastrelid
areonly mentioned in the corruption message if they are related to the specific corruption. Otherwise, just the
va_valueidis mentioned in the corruption message.
The visibility rules fix is different in v11, relying on a visibility check which more closely follows the
implementationof HeapTupleSatisfiesVacuumHorizon.
—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
