Re: Really unique session ID - PID + connection timestamp?

On 04/09/2016 01:30 AM, Durumdara wrote:
> Dear Everybody!
>
>
> In MS we had a "persistent lock" structure and method.
> This over transactions because based on real records in a real table
> with pri key (tablename + id).
>
> For garbaging we had a special session info.
> In MS the session id is smallint, so it can repeats after server
> restarts, but my coll. found a "session creation timestamp".
> This is a key which unique.
> With this we can check for died sessions and we can clean their records.

It might help to explain more what it is you are trying to achieve.

First I am not sure what you mean by 'persistent lock', especially as it
applies to Postgres?

Second, I assume by garbaging you mean garbage collection of something?
If that is the case what exactly are you garbage collecting?
I see 'clean records', what records would these be?
In particular, on Postgres, where are you going to do this?

>
> We want create same mechanism.

If the above questions did not already cover this, what mechanism?

> I know there are adv. locks in PG, but I want to use session id.
>
> This could be:
> |pg_backend_pid|()
>
> May pid repeats.
> Where I can get timestamp or some other unique data with I can create a
> combined primary key?
>
> Thanks for your help!
>
> dd
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com