Aaron Mulder writes:
> Well... we could certainly do that, but...
>
> The most reasonable way would be to use the DB-specific key
> generation, but that only works for DBs that support it (Oracle and
> PostgreSQL, that I'm aware of), and would require user configuration (to
> pick a DB). I suppose we could make a "generic" setting that just uses a
> normal DB table, but it would have to just keep issuing SQL like "update
> foo set counter = (value+1) where counter=(value)" until one went through,
> to avoid clashing with other instances.
Hmmm? That seems a bit inefficient, if I understand you correctly.
Why 'until one went through'? Why not have a table:
CREATE TABLE JBOSS_KEYGEN_SEQUENCE
(
IDENTIFIER INT4 NOT NULL PRIMARY KEY,
VALUE INT8 NOT NULL
)
INSERT INTO JBOSS_KEYGEN_SEQUENCE VALUES ( 1, 0 );
Then whenever you want a new key:
COMMIT; (or however your db begins a tx)
SELECT value FROM jboss_keygen_sequence WHERE identifier=1;
UPDATE jboss_keygen_sequence SET value = value+1 where identifier=1;
COMMIT;
Also, if you only use the db to generate half of a 128 bit key then
you only need to hit the database once in every 2^64 keys.
> Anyway, if you want me to go ahead and put such a thing together,
> say the word - any let me know if you can see a way to do it other than
> involving the DB.
As I said in a different post I have a key generator mbean, but it
uses Oracle sequences. Such a thing is not hard to put together,
though; it took me two hours, and that was including working out how
MBeans work.
Tom
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