ExecStoreTuple going into infinite loop

On Wed, Jun 6, 2012 at 5:36 AM, Atri Sharma <atri.jiit@gmail.com> wrote:

Hi all,

I am trying to build and store multiple tuples.The code is:

ExecClearTuple(slot);

/The code for fetching the data from which tuple will be formed../
for(;x<y;x++){
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(node->ss.ss_currentRelation->rd_att),
values);
ExecStoreTuple(tuple, slot, InvalidBuffer, false);
}

return (slot);

When I am including the ExecClearTuple(slot),the result only includes
the last tuple that was built.If I do not include
ExecClearTuple(slot),the code goes into an infinite loop.

Please help.

I've answered off list. The context here is fdw iteration. Atri was
trying to return multiple rows inside the iteration which is not how
the function is designed to work. (also this would be more
appropriate question for -general).

merlin

Atri Sharma <atri.jiit@gmail.com> writes:

Hi all,
I am trying to build and store multiple tuples.The code is:

ExecClearTuple(slot);

/The code for fetching the data from which tuple will be formed../
for(;x<y;x++){
tuple = BuildTupleFromCStrings(TupleDescGetAttInMetadata(node->ss.ss_currentRelation->rd_att),
values);
ExecStoreTuple(tuple, slot, InvalidBuffer, false);
}

return (slot);

When I am including the ExecClearTuple(slot),the result only includes
the last tuple that was built.

I am not sure why you find this surprising. A tuple slot can only hold
one tuple.

If you're trying to build a set-returning function, you need a
tuplestore not a tuple slot. Or else restructure the code to return
each tuple as it's built. Look at existing SRFs for examples.

regards, tom lane