Re: possible concurrency bug or mistake in understanding read-committed behavior

Jignesh Shah <jkshah@gmail.com> wrote:
> The question is should the delete fail if it doesn't exist and
> cause a rollback or succeed with DELETE 0 ?
I think existing behavior is consistent with both the standard and
the other behaviors of PostgreSQL at the READ COMMITTED isolation
level.  I might have found it surprising at first glance except that
there was a recent discussion about why an INSERT on one transaction
doesn't stand in the way of a concurrent UPDATE in another
transaction at that level.  (I don't want to exhibit surprise again
so soon -- it might scare Bruce.  ;-) )
This example does cause a serialization failure at the REPEATABLE
READ level as well as at the SERIALIZABLE level with the SSI patch,
which all seems sane to me, too.
-Kevin