Adding snapshot too old

Those of you using Oracle would be aware of the following error message: snapshot too old. In Oracle, this message indicates that a transaction has been too long, so it has to be aborted. In PostgreSQL, transactions can run almost infinitely. However, long transactions can still be a problem, so the snapshot too old error has been added as a feature to 9.6, which allows transactions to be aborted after a certain amount of time.

The idea behind that is to prevent table bloat and to make sure that end users are aware of the fact that they might be about to do something stupid.