Problems with the varlena patch in my module

Tzahi Fadida <Tzahi.ML@gmail.com> writes:

This is an excerpt from my code:
newtset->tids = (bytea *) fastgetattr(tupleTSet, LABELS_ALIGNED,
fctx->tupleSetDesc, &isnull);

It seems that for an empty bytea (only the size of the header), i get that
VARSIZE(newtset->tids)==534765440
instead of VARHDRSZ.

That code has always been broken, you just failed to exercise the
problem before. There needs to be a detoasting call there, not
merely a cast. DatumGetByteaP() would probably be appropriate.

regards, tom lane

On Saturday 07 April 2007 04:08:34 Tom Lane wrote:

Tzahi Fadida <Tzahi.ML@gmail.com> writes:

This is an excerpt from my code:
newtset->tids = (bytea *) fastgetattr(tupleTSet, LABELS_ALIGNED,
fctx->tupleSetDesc, &isnull);

It seems that for an empty bytea (only the size of the header), i get
that VARSIZE(newtset->tids)==534765440
instead of VARHDRSZ.

That code has always been broken, you just failed to exercise the

It always worked before the patch so it was hard to know that.
You see, i knew from the start that this attribute would never reach certain
sizes so i never thought it would be toasted.

problem before. There needs to be a detoasting call there, not
merely a cast. DatumGetByteaP() would probably be appropriate.

Thanks. One more question though, what is the CATALOG_VERSION_NO
of the varlena patch?

The second problem i have (it is a bit long but simple so please bear with
me):
You see, before there were slots (at least stable working slots)
tuples (slot_getattr, etc...), i needed this functionality.
So, i created the following function (which broke because of the varlena patch
on the att_align function):
bool
heap_deformtuple_iterative(HeapTuple tuple,
                                                   TupleDesc tupleDesc,
                                                   Datum *values,
                                                   char *nulls,
deformTupleIterativeState * ds,
                                                   int tillAttNum, bool
finishAll)

Where tuple is tuple,
tupleDesc is of course TupleDesc.
values are to store the deformed values (the array is already allocated).
nulls, same.
ds is a pointer to a structure i made to save the state of the
heap_deformtuple in mid work.
tillAttNum is a number of attributes from the start to deform up to.
finishAll - deform all the remaining attributes.

Now, i want to move to the more standard way to do this. However, i want to
keep the structure where i have a tuple->t (the tuple), tuple->v (the values
array), tuple->n (the nulls array). I keep many tuples in memory like this
and i can't change this now. I want to keep in memory only the heaptuple
tuple->t and the deformed arrays tuple->v, tuple->n and possibly another
needed (such as ds) structure for as long as the tuple is not completely
deformed.

What do you recommend (aside from me reimplementing the heap_deformtuple
iterative again hoping it won't break again)?

--
Regards,
        Tzahi.
--
Tzahi Fadida
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