Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Interesting. I wonder if it's possible that a relcache invalidation
> would cause these values to get lost for some reason, because that would
> be dangerous.
> I suppose the rationale is that this shouldn't happen because any
> operation that does things this way must hold an exclusive lock on the
> relation. But that doesn't guarantee that the relcache entry is
> completely stable,
It ABSOLUTELY is not safe. Relcache flushes can happen regardless of
how strong a lock you hold.
regards, tom lane