Re: Retrieving last InsertedID : INSERT... RETURNING safe ?

Dave Cramer wrote:
>
> On 20-Feb-08, at 7:19 AM, Paul Tomblin wrote:
>
>> Dave Cramer wrote:
>>>> Well, that other solution is dangerous in case multiple inserts
>>>> to that table are done concurrently; a quite common usage pattern
>>>> with java web applications handling multiple HTTP requests with
>>>> concurrent java threads..
>>>>
>>> No it is not dangerous. It is the right way to do it. There is
>>> absolutely no danger in using currval in this manner.
>>
>> Unless you have autocommit on.
>>
> I was going to say there are absolutely no situations where this is not
> true, however in your case autocommit or not it doesn't matter.
> You have a single connection for the entire application and asynchronous
> events using that connection. Autocommit or not it will not work with
> currval.
>
> In your case you must use nextval before doing the insert.

Now you lost me. By asynchronous events, do you mean NOTIFY/LISTEN? What
exactly is the scenario you're talking about?

One problematic scenario for nextval+currval is an INSERT trigger that
calls nextval() behind your back, but you can fool any method with a
trigger if you really want to.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com