Re: functions returning sets

Tom Lane wrote:
> Hmm, this looks like a bug having to do with not resetting state
> correctly for the next invocation of the SRF. Hard to tell whether
> the bug is in your code or the system's support for SRFs though.

Looks like a bug in ExecScanSubPlan() around line 401:
8<-----------------------------------------------------
if (subLinkType == ANY_SUBLINK)
{
/* combine across rows per OR semantics */
if (rownull)
*isNull = true;
else if (DatumGetBool(rowresult))
{
result = BoolGetDatum(true);
*isNull = false;
break; /* needn't look at any more rows */
}
}
8<-----------------------------------------------------

If the function returns a set, that comment is wrong, isn't it? I
removed the "break" to run out all the available tuples and got the
correct result:

regression=# select id from foo where 'a' in (select
pgxml_xpath(doc,'/top/node'));
id
----
1
2
3
(3 rows)

Any guidance on the preferred fix? I don't see an obvious way to
determine if the plan includes a set returning function in
ExecScanSubPlan(), and it seems unfortunate to remove the optimization
for all other cases, especially since targetlist SRFs are deprecated.

Joe