On Thu, Dec 8, 2022 at 12:56 AM Amin <amin.fall...@gmail.com> wrote: > > Hi All, > > I am trying to create HeapTuple data structure. > First, I create a tuple descriptor: > TupleDesc *td=CreateTemplateTupleDesc(colCount); > Then, for each variable, I do: > TupleDescInitEntry(*td,v->varattno,NULL,v->vartype,v->vartypmod,0); > Then, I assign values: > if int32: values[v->varattno-1]=Int8GetDatum(myValue); > Similarly for float. > Finally, I create the HeapTuple: > HeapTuple tuple=heap_form_tuple(td,values,isnull); > > Everything works fine with int and float. But I don't know how to handle > chars. > Let's say we have a character(10) column. One problem is v->vartypmod will be > set to 14. Shouldn't it be 10?
I think the 4 extra bytes is varlena header - not sure. but typmod in this case indicates the length of binary representation. 14 looks correct. > Second, how should I assign values? Is > values[v->varattno-1]=CStringGetDatum(myValue); correct? Should I set the > last parameter to TupleDescInitEntry? Why am I getting "invalid memory alloc > request size" or segfault with different configurations? is myValue a char *? I think you need to use CStringGetTextDatum instead of CStringGetDatum. -- Best Wishes, Ashutosh Bapat
