Michael Clark <codingninja(at)gmail(dot)com> writes:
> I have a database which appears to have some corruption in a toast value.
> When I select a certain table, I get the following error:
> ERROR: invalid page header in block 984 of relation "pg_toast_17341_index"
If it's only that index that has gotten damaged, REINDEX will fix it, eg
reindex index pg_toast.pg_toast_17341_index;
The bigger concern is whether there is other damage. Have you had any
system crashes, indications of flaky hardware, etc on that machine?
regards, tom lane