Tom Lane wrote:
> louis gonzales <gonzales@linuxlouis.net> writes:
>> As an example:
>> insertX which initiates the trigger reads the 'nextvalue' from the
>> sequence and begins to create the associcated table
>> insertY happens almost at the same time, so that it gets the same
>> 'nextvalue' from the sequence
That won't happen because of isolation :). When InsertX increments the
sequence, it is forever incremented, so when InsertY increments it gets
the next value... e.g;
CREATE TABLE foo(id serial);
Transaction 1:
BEGIN;
INSERT INTO foo(id) VALUES (DEFAULT);
id now == 1
Transaction 2:
BEGIN;
INSERT INTO foo(id) VALUES (DEFAULT);
id now == 2
Transaction 1;
COMMIT;
Transaction 2;
COMMIT;
Even if Transaction 1 were to rollback, it has already incremented the
sequence so the next transaction would get 3.
Joshua D. Drake
>
> [ blink... ] Whatever makes you think that could happen?
>
> regards, tom lane
>
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