On Fri, Nov 22, 2019 at 10:32:11PM +0000, Ranier Vilela wrote:
Hi,
This is real bug? firsttupleslot == NULL.
Ranier, I don't want to be rude, but I personally am getting a bit
annoyed by this torrent of bug reports that are essentially just a bunch
of copy-pasted chunks of code, without any specification of bench,
position in the file, etc.
And more importantly, without any clear explanation why you think it is
a bug (or even a demonstration of an issue), and "Is this a bug?"
\backend\executor\nodeGroup.c
if (TupIsNull(firsttupleslot))
{
outerslot = ExecProcNode(outerPlanState(node));
if (TupIsNull(outerslot))
{
/* empty input, so return nothing */
node->grp_done = true;
return NULL;
}
/* Copy tuple into firsttupleslot */
ExecCopySlot(firsttupleslot, outerslot);
include\executor\tuptable.h:
#define TupIsNull(slot) \
((slot) == NULL || TTS_EMPTY(slot))
static inline TupleTableSlot *
ExecCopySlot(TupleTableSlot *dstslot, TupleTableSlot *srcslot)
{
Assert(!TTS_EMPTY(srcslot));
dstslot->tts_ops->copyslot(dstslot, srcslot);
return dstslot;
}
And why do you think this is a bug? Immediately before the part of code
you copied we have this:
/*
* The ScanTupleSlot holds the (copied) first tuple of each group.
*/
firsttupleslot = node->ss.ss_ScanTupleSlot;
And node->ss.ss_ScanTupleSlot is expected to be non-NULL. So the initial
assumption that firsttupleslot is NULL is incorrect.
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
