Re: Intermittent missing chunk ERRORS

On Sat, 2025-04-26 at 11:09 -0600, Sbob wrote:
> I am working with a client, they have an app that is running into error's like this:
>
> SQL Error [XX001]: ERROR: missing chunk number 0 for toast value 44915477 in pg_toast_5321896
>
> I thought it was a corruption / REINDEX issue, however I have run REINDEXon the index,
> REINDEX on the table and even a reindexdb on the database. Today they passed me another
> error (the one above) and once I was able to login I ran the same query the app team
> referenced and it ran without any errors. I asked them to re-run the query and they
> informed me that it now works for them as well.
>
> I assume that if this were a corrupt index issue then the query would continue to fail
> every time.
>
> Has anyone seen this type of intermittent index error before? and thoughts on where to
> look /how to debug this?

The error is data corruption.

If it is transient, that could mean a couple of things:

- a TOAST index was corrupted, and REINDEX fixed it

- faulty RAM corrupted data, but as soon as the corrupted buffer was evicted,
the problem was gone

- somebody updated or deleted the row, and the corruption is hidden

Yours,
Laurenz Albe