Re: Error: missing chunk number ...

>
>
>Bizarre.  Evidently there's something broken about the TOAST data for
>your table.  I am thinking that the toast table's index might be
>corrupt, in which case you could probably recover by reindexing that
>index.
>

That's it! Doing the following fixed the problem:
./oid2name -d xxxxx-db -t rss_channels
Oid of table rss_channels from database "xxxxx-db":
_______________________________
796690 = rss_channels

backend> reindex index pg_toast_796690_idx;

I still don't know what caused this but I'll wait a bit and see how it 
goes -- this was not the first time I had this problem. In the past 
(couple of weeks), I  used to drop and recreate the table to resolve this.

Thanks for the help.

Best wishes,
Neophytos