It's hard to follow how the 2 videos relate, because you don't run the same SQL both places. You first update where i = 2 in Postgres and i = 1 in Oracle.
On Thu, Dec 21, 2017 at 4:37 AM, Hans Schou <hans.sc...@gmail.com> wrote: > Hi > > FYI - if it has any interest > > During my preparation for describing what happens when two processes > update the same row in a table, I came across that PostgreSQL is doing > right and Oracle is doing it wrong. > > The situation is a process which get a deadlock, but because it is a > script, it sends a commit anyway. This is bad behavior by humans but that's > how they are. > > After both processes commit's the table should be: > i | n > ---+--- > 1 | 11 > 2 | 21 > in Oracle it is: > i | n > ---+--- > 1 | 11 > 2 | 22 > > PostgreSQL: https://youtu.be/rH-inFRMcvQ > Oracle: https://youtu.be/l2IGoaWql64 > > PostgreSQL: > A > select * from t; > begin; > update t set n=n+1 where i=2; > > B > begin; > update t set n=n+1 where i=1; > update t set n=n+1 where i=2; > > A > update t set n=n+1 where i=1; > > B > commit; > > A > commit; > > best regards > hans >
