Hi,
On 2018-07-23 21:03:32 +0300, Mariel Cherkassky wrote:
> Today I faced a situation where I saw a postgresql 9.2 database that had
> duplicated rows in pg_autid. I saw 6 roles while 3 of them were duplicated
> (3 uniques rolenames in total). I checked and the oid of the duplicates
> were the same oid as the originals. The solution was running vacuum on the
> table but I wanted to understand how this situation was created ? Why even
> with unique index on the rolname I saw duplicated values for rolname ?
That suggests some form of corruption. Which version of 9.2 did this
occur on? Did you have any OS level crashes? Ran with fsync=off?
Please note that 9.2 is not supported anymore.
Greetings,
Andres Freund