In our application we use Hibernate and PostgreSQL to store data. In one of our database tables we have a discriminator column which says for example "TIPPSPIEL". It is a fixed string and can not be manipulated by any user.
Suddenly we had one entry in this huge table where we had "TIPPQPIEL" instead of "TIPPSPIEL". We have no clue how this can happen.
Is it possible by any means that our hard disk is switching one bit, so our letter "S" is no longer encoded as "1010001" but suddenly becomes a "Q" on the hard disk with one bit switched like this: 1010011?
I am not an expert on hard disk an bit physics but I guess an OS or a disk has checksums and other stuff to ensure that this can't happen.
Is it possible that just one bit switches so my file shows me a letter "Q" instead of a "S"?
UPDATE: We made further analyse. Our slave database gets its WAL Records from master (PostgreSQL feature). Whatever: our slave server should be in sync. But the slave wasn't in sync regarding this particular row. We could see that it happened a few days ago without any interaction from a user on this particular entry. So it MUST be a bit flipping around. scary!