Re: [BUGS] Status of issue 4593

Tom Lane wrote:
> "Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
>> Tom Lane <tgl@sss.pgh.pa.us> wrote: 
>>> A re-sort after locking doesn't really make things all nice and
>>> intuitive either.
> 
>> Would it make any sense to roll back and generate a
>> SERIALIZATION_FAILURE?
> 
> If that's what you want then you run the transaction in serializable
> mode.  The point of doing it in READ COMMITTED mode is that you don't
> want such a failure.

Well, you can get deadlocks in read committed mode, so it is not like 
this mode is totally free of concurrency related failure possibilities.

Both serialization errors and deadlocks assume a write operation though.

But could we detect this case at all?  That is, when we are re-reading 
the updated tuple, do we remember that we did some sorting earlier?