Re: Transaction isolation with concurrent increments

Nico Erichsen <nico.e@gmx.de> writes:
>     set transaction isolation level serializable;
>     begin;
>     update counters set counter1=(select counter1+1 from counters);

Try it the other way round:

     begin;
     set transaction isolation level serializable;
     update counters set counter1=(select counter1+1 from counters);

Isolation level is a transaction-local setting so the first way doesn't
affect the level the BEGIN block actually uses.  (There is a SET
variable to change the default level for future transactions, but that
ain't what you set here.)

            regards, tom lane