Re: BUG #16662: pgbench: error: client 418 script 0 aborted in command 5 query 0: ERROR: invalid page in block 4830

On Thu, Oct 08, 2020 at 03:49:58PM +0000, PG Bug reporting form wrote:
> During the pressure test using pgbench, the following error occurred, but
> the object with oid=16396 was queried through pg_class, and it did not
> exist. Is this a bug?

Unlikely one in Postgres itself, I would recommend to be very careful
with this instance :(

A data checksum failure, as the one you are seeing here, means that an
8k page of a relation file that Postgres has flushed out to disk in
the past has been loaded back with some unexpected data. This means
that a source external to Postgres has changed this data. I have seen
this class of failures with problems involving either the kernel, the
file system, the hardware, or even some layer in charge of the host
virtualization, if your host is a VM of course. So something has
likely managed the flush request thought as completed by Postgres in a
non-durable way, or something could have directly changed the on-disk
data with the flush request actually done correctly, which is even a
worse problem. What this error tells is that the problem does not
come from Postgres itself.
--
Michael