Re: currval and DISCARD ALL

On 04/15/2013 05:57 PM, Adrian Klaver wrote:
> On 04/15/2013 02:42 PM, Nigel Heron wrote:
>> Hi,
>> is there a way to clear the session state of sequence values fetched by
>> currval(regclass)? "DISCARD ALL" doesn't seem to do it.
>>
<snip>
> Might want to take a look at:
>
> http://www.depesz.com/2012/12/02/what-is-the-point-of-bouncing/
>
> for some hints on dealing with sequences and pgBouncer.
>

thanks, I read it (his blogs are always interesting!). I'm not disputing
that calling currval() at the wrong time is a bad idea.
I'm just wondering why DISCARD ALL clears everything but this?
from the docs:
"DISCARD ALL resets a session to its original state, discarding
temporary resources and resetting session-local configuration changes."
.. but at the beginning of a session currval(foo) would return an error,
whereas calling nexval(foo); DISCARD ALL; currval(foo); does not return
an error.. clearly something isn't getting reset to the original state.

If you create a TEMP sequence, then DISCARD ALL does clear the state,
probably because the underlying table disappears.

-nigel.