Re: ALTER SYSTEM RESET?

On Wed, Jun 25, 2014 at 9:56 PM, Vik Fearing <vik(dot)fearing(at)dalibo(dot)com> wrote:
> On 06/25/2014 03:04 PM, Amit Kapila wrote:
> > Currently you can achieve that by
> > "ALTER SYSTEM RESET guc = Default;".
> > However it will be good to have support for RESET as well. I think it
> > should not be too complicated to implement that syntax, I personally
> > don't have bandwidth to it immediately, but I would like to take care
> > of it unless you or someone wants to do it by the time I get some
> > bandwidth.
>
> Would something like this suffice?

I think it will make sense if we support RESET ALL as well similar
to Alter Database .. RESET ALL syntax. Do you see any reason
why we shouldn't support RESET ALL syntax for Alter System?

About patch:

+ | ALTER SYSTEM_P RESET var_name
+ {
+ AlterSystemStmt *n = makeNode(AlterSystemStmt);
+ n->setstmt = makeNode(VariableSetStmt);
+ n->setstmt->kind = VAR_RESET;
+ n->setstmt->name = $4;
+ $ = (Node *)n;
+ }

I think it would be better to have ALTER SYSTEM_P as generic and
then SET | RESET as different versions, something like below:

| SET reloptions
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_SetRelOptions;
n->def = (Node *)$2;
$$ = (Node *)n;
}
/* ALTER TABLE <name> RESET (...) */
| RESET reloptions
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_ResetRelOptions;
n->def = (Node *)$2;
$$ = (Node *)n;
}

Another point is that if we decide to support RESET ALL syntax, then
we might want reuse VariableResetStmt, may be by breaking into
generic and specific like we have done for generic_set.

Thanks for working on patch.

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com